source: tags/arb-6.0/GDE/TREEPUZZLE/src/ml2.c

/*
 * ml2.c
 *
 *
 * Part of TREE-PUZZLE 5.0 (June 2000)
 *
 * (c) 1999-2000 by Heiko A. Schmidt, Korbinian Strimmer,
 *                  M. Vingron, and Arndt von Haeseler
 * (c) 1995-1999 by Korbinian Strimmer and Arndt von Haeseler
 *
 * All parts of the source except where indicated are distributed under
 * the GNU public licence.  See http://www.opensource.org for details.
 */


#define EXTERN extern

/* prototypes */
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <ctype.h>
#include <string.h>
#include "util.h"
#include "ml.h"

#define STDOUT     stdout
#ifndef PARALLEL             /* because printf() runs significantly faster */
                             /* than fprintf(stdout) on an Apple McIntosh  */
                             /* (HS) */
#       define FPRINTF    printf
#       define STDOUTFILE
#else
#       define FPRINTF    fprintf
#       define STDOUTFILE STDOUT,
#endif

/* prototypes for two functions of puzzle2.c */
void fputid10(FILE *, int);
int fputid(FILE *, int);


/******************************************************************************/
/* user tree input                                                            */
/******************************************************************************/

/* read user tree, drop all blanks, tabs, and newlines.
   Drop edgelengths (after :) but keep internal
   labels. Check whether all pairs of brackets match. */
void getusertree(FILE *itfp, cvector tr, int maxlen)
{
        int n, brac, ci;
        int comment = 0;

        /* look for opening bracket */
        n = 0;
        brac = 0;
        do {
                ci = fgetc(itfp);
                if (ci == EOF) {
                        FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (missing start bracket in tree)\n\n\n");
                        exit(1);
                }
                if (ci == '[') comment = 1;
                if ((ci == ']') && comment) {
                        comment = 0;
                        ci = fgetc(itfp);
                }
        } while (comment || ((char) ci != '('));
        tr[n] = (char) ci;
        brac++;
        
        do {
                /* get next character (skip blanks, newlines, and tabs) */
                do {
                        ci = fgetc(itfp);
                        if (ci == EOF) {
                                FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (no more characters in tree)\n\n\n");
                                exit(1);
                        }
                        if (ci == '[') comment = 1;
                        if ((ci == ']') && comment) {
                                comment = 0;
                                ci = fgetc(itfp);
                        }
                } while (comment || (char) ci == ' ' || (char) ci == '\n' || (char) ci == '\t');
        
                if ((char) ci == ':') { /* skip characters until a ,) appears  */
                        do {
                                ci = fgetc(itfp);
                                if (ci == EOF) {
                                        FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (missing ';' or ',' in tree)\n\n\n");
                                        exit(1);
                                }
                                if (ci == '[') comment = 1;
                                if ((ci == ']') && comment) {
                                        comment = 0;
                                        ci = fgetc(itfp);
                                }
                        } while (comment || ((char) ci != ',' && (char) ci != ')') );
                }
                
                if ((char) ci == '(') {
                        brac++;
                }
                if ((char) ci == ')') {
                        brac--;
                }

                n++;
                tr[n] = (char) ci;
        
        } while (((char) ci != ';') && (n != maxlen-2));
        
        if (n == maxlen-2) {
                FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (tree description too long)\n\n\n");
                exit(1);
        }
        
        if (brac != 0) {
                FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (brackets don't match in tree)\n\n\n");
                exit(1);
        }
        
        n++;
        tr[n] = '\0';
}


Node *internalnode(Tree *tr, char **chpp, int *ninode)
{
        Node *xp, *np, *rp;
        int i, j, dvg, ff, stop, numc;
        char ident[100], idcomp[11];
        char *idp;

        (*chpp)++;
        if (**chpp == '(') { /* process subgroup */
                
                xp = internalnode(tr, chpp, ninode);
                xp->isop = xp;
                dvg = 1;
                while (**chpp != ')') {
                        if (**chpp == '\0') {
                                FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (unexpected end of tree)\n\n\n");
                                exit(1);
                        }
                        dvg++;
                        /* insert edges around node */
                        np = internalnode(tr, chpp, ninode);
                        np->isop = xp->isop;
                        xp->isop = np; 
                        xp = np;
                }
                /* closing bracket reached */
                
                (*chpp)++;
                if (dvg < 2) {
                        FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (only one OTU inside pair of brackets)\n\n\n");
                        exit(1);
                }
                
                if ((*ninode) >= Maxspc-3) { /* all internal nodes already used */
                        FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (no unrooted tree)\n\n\n");
                        exit(1);
                }

                rp = tr->ibrnchp[*ninode];
                rp->isop = xp->isop;
                xp->isop = rp;

                for (j = 0; j < Numspc; j++)
                        rp->paths[j] = 0;
                xp = rp->isop;
                while (xp != rp) {
                        for (j = 0; j < Numspc; j++) {
                                if (xp->paths[j] == 1)
                                        rp->paths[j] = 1;
                        }
                        xp = xp->isop;
                }
                (*ninode)++;

                if ((**chpp) == ',' || (**chpp) == ')') return rp->kinp;
                if ((**chpp) == '\0')  {
                        FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (unexpected end of tree)\n\n\n");
                        exit(1);
                }

                /* read internal label into rp->label (max. 20 characters) */
                rp->label = new_cvector(21);
                (rp->label)[0] = **chpp;
                (rp->label)[1] = '\0';
                for (numc = 1; numc < 20; numc++) {
                        (*chpp)++;
                        if ((**chpp) == ',' || (**chpp) == ')') return rp->kinp;
                        if ((**chpp) == '\0')  {
                                FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (unexpected end of tree)\n\n\n");
                                exit(1);
                        }
                        (rp->label)[numc] = **chpp;
                        (rp->label)[numc+1] = '\0';
                }       
                do { /* skip the rest of the internal label */
                        (*chpp)++;
                        if ((**chpp) == '\0')  {
                                FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (unexpected end of tree)\n\n\n");
                                exit(1);
                        }
                } while (((**chpp) != ',' && (**chpp) != ')'));
                        
                return rp->kinp;
                
        } else { /* process species names */
                /* read species name */
                for (idp = ident; **chpp != ',' &&
                        **chpp != ')' && **chpp != '\0'; (*chpp)++) {
                        *idp++ = **chpp;        
                }
                *idp = '\0';
                /* look for internal number */
                idcomp[10] = '\0';
                
                for (i = 0; i < Maxspc; i++) {
                        ff = 0;
                        stop = FALSE;
                        do {
                                idcomp[ff] = Identif[i][ff];
                                ff++;
                                if (idcomp[ff-1] == ' ') stop = TRUE;
                        } while (!stop && (ff != 10));
                        if (stop) idcomp[ff-1] = '\0';
                        
                        if (!strcmp(ident, idcomp)) {
                                if (usedtaxa[i]) {
                                        FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (multiple occurrences of sequence '");
                                        FPRINTF(STDOUTFILE "%s' in tree)\n\n\n", ident);
                                        exit(1);
                                }
                                usedtaxa[i] = TRUE;
                                return tr->ebrnchp[i]->kinp;
                        }
                }
                
                FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (unknown sequence '%s' in tree)\n\n\n", ident);
                exit(1);
        }
        return NULL; /* never returned but without some compilers complain */
}

/* make tree structure, the tree description may contain internal
    labels but no edge lengths */
void constructtree(Tree *tr, cvector strtree)
{
        char *chp;
        int ninode, i;
        int dvg, numc;
        Node *xp, *np;

        ninode = 0;
        chp = strtree;
        usedtaxa = new_ivector(Maxspc);
        for (i = 0; i < Maxspc; i++) usedtaxa[i] = FALSE;

        xp = internalnode(tr, &chp, &ninode);
        xp->isop = xp;
        dvg = 1;
        while (*chp != ')') { /* look for closing bracket */
                if (*chp == '\0') {
                        FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (unexpected end of tree)\n\n\n");
                        exit(1);
                }
                dvg++;
                /* insert edges around node */
                np = internalnode(tr, &chp, &ninode);
                np->isop = xp->isop;
                xp->isop = np; 
                xp = np;
        }
        
        for (i = 0; i < Maxspc; i++)
                if (usedtaxa[i] == FALSE) {
                        FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (sequences missing in tree)\n\n\n");
                        exit(1);        
                }
        
        /* closing bracket reached */
        if (dvg < 3) {
                FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (no unrooted tree)\n\n\n");
                exit(1);
        }
        tr->rootp = xp;
        Numibrnch = ninode;
        Numbrnch = Numspc + ninode;

        chp++;
        if (*chp == ';' || *chp == '\0') {
                free_ivector(usedtaxa);
                return;
        }

        /* copy last internal label (max. 20 characters) */
        xp->label = new_cvector(21);
        (xp->label)[0] = *chp;
        (xp->label)[1] = '\0';          
        for (numc = 1; numc < 20; numc++) {
                chp++;
                if (*chp == ';' || *chp == '\0') {
                        free_ivector(usedtaxa);
                        return;
                } else {
                        (xp->label)[numc] = *chp;
                        (xp->label)[numc+1] = '\0';
                }
        }
        free_ivector(usedtaxa); 
        return;
}


/* remove possible basal bifurcation */
void removebasalbif(cvector strtree)
{
        int n, c, brak, cutflag, h;
        
        /* check how many OTUs on basal level */
        n = 0;
        c = 0;
        brak = 0;
        do {
                if (strtree[n] == '(') brak++;
                if (strtree[n] == ')') brak--;
                
                if (strtree[n] == ',' && brak == 1) c++; /* number of commas in outer bracket */
                
                n++;
        } while (strtree[n] != '\0');
        
        /* if only 1 OTU inside outer bracket stop now */
        if (c == 0) {
                FPRINTF(STDOUTFILE "\n\n\nUnable to proceed (Only 1 OTU inside outer bracket in tree)\n\n\n");
                exit(1);
        }       
        
        /* if only 2 OTUs inside outer bracket delete second pair of
           brackets from the right to remove basal bifurcation */

        if (c == 1) {
                        
                n = 0;
                brak = 0;
                cutflag = 0; /* not yet cutted */
                h = 0;
                do {
                        if (strtree[n] == '(') brak++;
                        if (strtree[n] == ')') brak--;
                        
                        if (brak == 2 && cutflag == 0) cutflag = 1; /* cutting */
                        if (brak == 1 && cutflag == 1) {
                                cutflag = 2; /* cutted */
                                /* leave out internal label */
                                do {
                                        h++;    
                                } while (strtree[n+h] != ')' && strtree[n+h] != ',');

                        }
                        
                        if (cutflag == 1) strtree[n] = strtree[n+1];
                        if (cutflag == 2) strtree[n-1] = strtree[n+h];
                
                        n++;
                } while (strtree[n] != '\0');
        }
}


void makeusertree(FILE *itfp)
{
        cvector strtree;
        
        strtree = new_cvector(23*Maxspc); /* for treefile */ 
        getusertree(itfp, strtree, 23*Maxspc);
        removebasalbif(strtree);
        constructtree(Ctree, strtree);
        free_cvector(strtree);
}


/******************************************************************************/
/* memory organisation for maximum likelihood tree                            */
/******************************************************************************/

/* initialise new tree */
Tree *new_tree(int maxspc, int numptrn, cmatrix seqconint)
{
        int n, i, maxibrnch;
        Tree *tr;
        Node *dp, *up;
        
        maxibrnch = maxspc - 3;
        heights = (Node **) malloc((unsigned)(maxspc-2) * sizeof(Node *));
        if (heights == NULL) maerror("heights in new_tree");
        tr = (Tree *) malloc(sizeof(Tree));
        if (tr == NULL) maerror("tr in new_tree");
        tr->ebrnchp = (Node **) malloc((unsigned)maxspc * sizeof(Node *));
        if (tr->ebrnchp == NULL) maerror("ebrnchp in new_tree");
        tr->ibrnchp = (Node **) malloc((unsigned)maxibrnch * sizeof(Node *));
        if (tr->ibrnchp == NULL) maerror("ibrnchp in new_tree");
        tr->condlkl = new_dmatrix(numcats, numptrn);    
        for (n = 0; n < maxspc; n++) {
                dp = (Node *) malloc(sizeof(Node));
                if (dp == NULL) maerror("dp in new_tree");
                up = (Node *) malloc(sizeof(Node));
                if (up == NULL) maerror("up in new_tree");
                dp->isop = NULL;
                up->isop = NULL;
                dp->kinp = up;
                up->kinp = dp;
                dp->descen = TRUE;
                up->descen = FALSE;
                dp->number = n;
                up->number = n;
                dp->length = 0.0;
                up->length = 0.0;
                dp->lengthc = 0.0;
                up->lengthc = 0.0;
                dp->varlen = 0.0;
                up->varlen = 0.0;
                dp->paths = new_ivector(maxspc);
                up->paths = dp->paths;
                for (i = 0; i < maxspc; i++) dp->paths[i] = 0;
                dp->paths[n] = 1;
                dp->eprob = seqconint[n];
                up->eprob = NULL;
                dp->partials = NULL;
                up->partials = new_dcube(numcats, numptrn, tpmradix);
                tr->ebrnchp[n] = dp;
                up->label = NULL;
                dp->label = NULL;
        }
        for (n = 0; n < maxibrnch; n++) {
                dp = (Node *) malloc(sizeof(Node));
                if (dp == NULL) maerror("dp in new_tree");
                up = (Node *) malloc(sizeof(Node));
                if (up == NULL) maerror("up in new_tree");
                dp->isop = NULL;
                up->isop = NULL;
                dp->kinp = up;
                up->kinp = dp;
                dp->descen = TRUE;
                up->descen = FALSE;
                dp->number = n;
                up->number = n;
                dp->length = 0.0;
                up->length = 0.0;
                dp->lengthc = 0.0;
                up->lengthc = 0.0;
                dp->varlen = 0.0;
                up->varlen = 0.0;
                dp->paths = new_ivector(maxspc);
                up->paths = dp->paths;
                for (i = 0; i < maxspc; i++) dp->paths[i] = 0;
                dp->eprob = NULL;
                up->eprob = NULL;
                dp->partials = new_dcube(numcats, numptrn, tpmradix);
                up->partials = new_dcube(numcats, numptrn, tpmradix);
                tr->ibrnchp[n] = dp;
                up->label = NULL;
                dp->label = NULL;
        }
        tr->rootp = NULL;
        
        /*
         * reserve memory for lengths of the tree branches
         * and for the distance matrix as a vector
         * (needed for LS estimation of tree branch lengths)
         */ 
         
        Brnlength = new_dvector(2 * maxspc - 3); 
        Distanvec = new_dvector((maxspc * (maxspc - 1)) / 2);

        return tr;
}


/* initialise quartet tree */
Tree *new_quartet(int numptrn, cmatrix seqconint)
{
        int n, i;
        Tree *tr;
        Node *dp, *up;

        heights = (Node **) malloc((unsigned)2 * sizeof(Node *));
        if (heights == NULL) maerror("heights in new_quartet");
        /* reserve memory for tree */
        tr = (Tree *) malloc(sizeof(Tree));
        if (tr == NULL) maerror("tr in new_quartet");
        tr->ebrnchp = (Node **) malloc((unsigned) 4 * sizeof(Node *));
        if (tr->ebrnchp == NULL) maerror("ebrnchp in new_quartet");
        tr->ibrnchp = (Node **) malloc((unsigned) sizeof(Node *));
        if (tr->ibrnchp == NULL) maerror("ibrnchp in new_quartet");
        tr->condlkl = new_dmatrix(numcats, numptrn);
        /* reserve memory for nodes */
        for (n = 0; n < 4; n++) {
                dp = (Node *) malloc(sizeof(Node));
                if (dp == NULL) maerror("dp in new_quartet");
                up = (Node *) malloc(sizeof(Node));
                if (up == NULL) maerror("dp in new_quartet");
                dp->isop = NULL;
                dp->kinp = up;
                up->kinp = dp;
                dp->descen = TRUE;
                up->descen = FALSE;
                dp->number = n;
                up->number = n;
                dp->length = 0.0;
                up->length = 0.0;
                dp->lengthc = 0.0;
                up->lengthc = 0.0;
                dp->varlen = 0.0;
                up->varlen = 0.0;
                dp->paths = new_ivector(4);
                up->paths = dp->paths;
                for (i = 0; i < 4; i++) dp->paths[i] = 0;
                dp->paths[n] = 1;
                dp->eprob = seqconint[n]; /* make quartet (0,1)-(2,3) as default */
                up->eprob = NULL;               
                dp->partials = NULL;
                up->partials = new_dcube(numcats, numptrn, tpmradix);
                tr->ebrnchp[n] = dp;
        }

        /* reserve memory for internal branch */        
        dp = (Node *) malloc(sizeof(Node));
        if (dp == NULL) maerror("dp in new_quartet");   
        up = (Node *) malloc(sizeof(Node));
        if (up == NULL) maerror("dp in new_quartet");   
        dp->isop = tr->ebrnchp[3]->kinp; /* connect internal branch */
        up->isop = tr->ebrnchp[0]->kinp;
        dp->kinp = up;
        up->kinp = dp;
        dp->descen = TRUE;
        up->descen = FALSE;
        dp->number = 0;
        up->number = 0;
        dp->length = 0.0;
        up->length = 0.0;
        dp->lengthc = 0.0;
        up->lengthc = 0.0;
        dp->varlen = 0.0;
        up->varlen = 0.0;
        dp->paths = new_ivector(4);
        up->paths = dp->paths;
        up->paths[0] = 0;
        up->paths[1] = 0;
        up->paths[2] = 1;
        up->paths[3] = 1;
        dp->eprob = NULL;
        up->eprob = NULL;       
        dp->partials = new_dcube(numcats, numptrn, tpmradix);
        up->partials = new_dcube(numcats, numptrn, tpmradix);   
        tr->ibrnchp[0] = dp;
        
        /* place root */
        tr->rootp = up;

        /* connect external branches */ 
        tr->ebrnchp[0]->kinp->isop = tr->ebrnchp[1]->kinp;
        tr->ebrnchp[1]->kinp->isop = tr->rootp;
        tr->ebrnchp[3]->kinp->isop = tr->ebrnchp[2]->kinp;
        tr->ebrnchp[2]->kinp->isop = tr->rootp->kinp;
        
        /*
         * reserve memory for lengths of the five branches
         * of a quartet and for the six possible distances
         * (needed for LS estimation of branch lengths)
         */
        Brnlength = new_dvector(NUMQBRNCH); 
        Distanvec = new_dvector(NUMQSPC*(NUMQSPC-1)/2);

        return tr;
}


/* free tree memory */
void free_tree(Tree *tr, int taxa)
{       
        int n;
        Node *dp, *up;

        free(heights);
        free_dmatrix(tr->condlkl);
        for (n = 0; n < taxa; n++) {
                dp = tr->ebrnchp[n];
                up = dp->kinp;
                free_ivector(dp->paths);                
                free_dcube(up->partials);               
                free(dp);
                free(up);
        }
        free(tr->ebrnchp);
        for (n = 0; n < (taxa-3); n++) {
                dp = tr->ibrnchp[n];
                up = dp->kinp;
                free_dcube(dp->partials);
                free_dcube(up->partials);
                free_ivector(dp->paths);
                free(dp);
                free(up);
        }
        free(tr->ibrnchp);
        free(tr);
        free_dvector(Brnlength); /* branch lengths (for LS estimation) */
        free_dvector(Distanvec); /* distances (for LS estimation) */
}


/* make (a,b)-(c,d) quartet

        a ---+     +--- c
             +-----+
        b ---+     +--- d

        species numbers range from 0 to Maxspc - 1  */

void make_quartet(int a, int b, int c, int d)
{
        /* place sequences */
        Ctree->ebrnchp[0]->eprob = Seqpat[a];
        Ctree->ebrnchp[1]->eprob = Seqpat[b];
        Ctree->ebrnchp[2]->eprob = Seqpat[c];
        Ctree->ebrnchp[3]->eprob = Seqpat[d];
        
        /* make distance vector */
        Distanvec[0] = Distanmat[b][a];
        Distanvec[1] = Distanmat[c][a];
        Distanvec[2] = Distanmat[c][b];
        Distanvec[3] = Distanmat[d][a];
        Distanvec[4] = Distanmat[d][b];
        Distanvec[5] = Distanmat[d][c];
}

/* write distance matrix as vector */
void changedistan(dmatrix distanmat, dvector distanvec, int numspc)
{
        int i, j, k;

        for (k = 0, i = 1; i < numspc; i++) {
                for (j = 0; j < i; j++, k++)
                        distanvec[k] = distanmat[i][j];
        }
}


/******************************************************************************/
/* computation of maximum likelihood tree                                     */
/******************************************************************************/


/* compute the likelihood for (a,b)-(c,d) quartet */
double quartet_lklhd(int a, int b, int c, int d)
{
        /* reserve memory for quartet if necessary */
        if (mlmode != 1) { /* no quartet tree */
                if (Ctree != NULL)
                        free_tree(Ctree, Numspc);
                Ctree = new_quartet(Numptrn, Seqpat);
                Numbrnch = NUMQBRNCH;
                Numibrnch = NUMQIBRNCH;
                Numspc = NUMQSPC;
                mlmode = 1;
        }
        
        /* make (a,b)-(c,d) quartet */
        make_quartet(a,b,c,d);

        clockmode = 0; /* nonclocklike branch lengths */
        
        /* least square estimate for branch length */   
        lslength(Ctree, Distanvec, Numspc, Numibrnch, Brnlength);

        /* compute likelihood */
        Ctree->lklhd = optlkl(Ctree);

        return Ctree->lklhd;
}


/* compute the approximate likelihood for (a,b)-(c,d) quartet */
double quartet_alklhd(int a, int b, int c, int d)
{
        /* reserve memory for quartet if necessary */
        if (mlmode != 1) { /* no quartet tree */
                if (Ctree != NULL)
                        free_tree(Ctree, Numspc);
                Ctree = new_quartet(Numptrn, Seqpat);
                Numbrnch = NUMQBRNCH;
                Numibrnch = NUMQIBRNCH;
                Numspc = NUMQSPC;
                mlmode = 1; 
        }
        
        /* make (a,b)-(c,d) quartet */
        make_quartet(a,b,c,d);

        clockmode = 0; /* nonclocklike branch lengths */
        
        /* least square estimate for branch length */   
        lslength(Ctree, Distanvec, Numspc, Numibrnch, Brnlength);

        /* compute likelihood */
        Ctree->lklhd = treelkl(Ctree);

        return Ctree->lklhd;
}


/* read usertree from file to memory */
void readusertree(FILE *ifp)
{
        /* reserve memory for tree if necessary */
        if (mlmode != 2) { /* no tree */
                if (Ctree != NULL)
                        free_tree(Ctree, Numspc);
                Ctree = new_tree(Maxspc, Numptrn, Seqpat);
                Numbrnch = 2*Maxspc-3;
                Numibrnch = Maxspc-3;
                Numspc = Maxspc;
                mlmode = 2;
        }

        /* read tree */
        makeusertree(ifp);
}


/* compute the likelihood of a usertree */
double usertree_lklhd()
{
        /* be sure to have a usertree in memory and
           to have pairwise distances computed */

        clockmode = 0; /* nonclocklike branch lengths */

        /* least square estimate for branch length */
        changedistan(Distanmat, Distanvec, Numspc);     
        lslength(Ctree, Distanvec, Numspc, Numibrnch, Brnlength);

        /* compute likelihood */
        Ctree->lklhd = optlkl(Ctree);

        return Ctree->lklhd;
}


/* compute the approximate likelihood of a usertree */
double usertree_alklhd()
{
        /* be sure to have a usertree in memory and
           to have pairwise distances computed */

        clockmode = 0; /* nonclocklike branch lengths */

        /* least square estimate for branch length */
        changedistan(Distanmat, Distanvec, Numspc);
        lslength(Ctree, Distanvec, Numspc, Numibrnch, Brnlength);

        /* compute likelihood */
        Ctree->lklhd = treelkl(Ctree);

        return Ctree->lklhd;
}


/* preparation for ML analysis */
void mlstart()
{
        /* number of states and code length */
        tpmradix = gettpmradix();
        
        /* declare variables */
        Eval = new_dvector(tpmradix);
        Evec = new_dmatrix(tpmradix,tpmradix);
        Ievc = new_dmatrix(tpmradix,tpmradix);
        iexp = new_dmatrix(tpmradix,tpmradix);
        Alias = new_ivector(Maxsite);
        
        /* process sequence information */
        evaluateseqs();
        bestrate = new_ivector(Numptrn);

        /* compute transition probability matrix */     
        tranprobmat();

        /* non-zero rate categories */
        Rates = new_dvector(numcats);
        updaterates();
        ltprobr = new_dcube(numcats, tpmradix,tpmradix);

        /* compute distance matrix */
        Distanmat = new_dmatrix(Maxspc, Maxspc);
        initdistan();
                
        /* initialize tree pointer for quartet tree */
        mlmode = 1;
        Ctree = new_quartet(Numptrn, Seqpat);
        Numbrnch = NUMQBRNCH;
        Numibrnch = NUMQIBRNCH;
        Numspc = NUMQSPC;

        /* computing ML distances */
        computedistan();
}


/* recompute ml distances for quartet only */
void distupdate(int a, int b, int c, int d)
{
        /* update distance matrix */
        /* consider only entries relevant to quartet */
        Distanmat[a][b] = mldistance(a, b);
        Distanmat[b][a] = Distanmat[a][b];
        Distanmat[a][c] = mldistance(a, c);
        Distanmat[c][a] = Distanmat[a][c];
        Distanmat[a][d] = mldistance(a, d);
        Distanmat[d][a] = Distanmat[a][d];
        Distanmat[b][c] = mldistance(b, c);
        Distanmat[c][b] = Distanmat[b][c];
        Distanmat[b][d] = mldistance(b, d);
        Distanmat[d][b] = Distanmat[b][d];
        Distanmat[c][d] = mldistance(c, d);
        Distanmat[d][c] = Distanmat[c][d];
}


/* cleanup after ML analysis */
void mlfinish()
{
        if (Ctree != NULL)
                free_tree(Ctree, Numspc);
        free_ivector(bestrate);
        free_ivector(Alias);
        free_cmatrix(Seqpat);
        free_ivector(constpat);
        free_ivector(Weight);
        free_dmatrix(Distanmat);
        free_dvector(Eval);
        free_dmatrix(Evec);
        free_dmatrix(Ievc);
        free_dvector(Rates);
        free_dcube(ltprobr);
        free_dmatrix(iexp);
}


/******************************************************************************/
/* tree output                                                                */
/******************************************************************************/


#define MAXOVER    50
#define MAXLENG    30
#define MAXCOLUMN  80


void prbranch(Node *up, int depth, int m, int maxm,
        ivector umbrella, ivector column, FILE *outfp)
{
        int i, num, n, maxn, lim;
        Node *cp;
        char bch;

        if ((int)((clockmode ? up->lengthc : up->length) * Proportion) >= MAXOVER) {
                column[depth] = MAXLENG;
                bch = '+';
        } else {
                column[depth] = (int)((clockmode ? up->lengthc : up->length) * Proportion) + 3;
                bch = '-';
        }

        if (up->isop == NULL) { /* external branch */
                num = up->number + 1; /* offset */
                if (m == 1) umbrella[depth - 1] = TRUE;
                for (i = 0; i < depth; i++) {
                        if (umbrella[i])
                                fprintf(outfp, "%*c", column[i], ':');
                        else
                                fprintf(outfp, "%*c", column[i], ' ');
                }
                if (m == maxm)
                        umbrella[depth - 1] = FALSE;
                for (i = 0, lim = column[depth] - 3; i < lim; i++)
                        fputc(bch, outfp);
                fprintf(outfp, "-%d ", num);
                                
                fputid(outfp, up->number);
                
                
                fputc('\n', outfp);
                fputc(' ', outfp);
                return;
        }

        num = up->number + 1 + Numspc; /* offset, internal branch */
        for (cp = up->isop, maxn = 0; cp != up; cp = cp->isop, maxn++)
                ;
        for (cp = up->isop, n = 1; cp != up; cp = cp->isop, n++) {
                prbranch(cp->kinp, depth + 1, n, maxn, umbrella, column, outfp);
                if (m == 1 && n == maxn / 2) umbrella[depth - 1] = TRUE;
                if (n != maxn) {
                        for (i = 0; i < depth; i++) {
                                if (umbrella[i])
                                        fprintf(outfp, "%*c", column[i], ':');
                                else
                                        fprintf(outfp, "%*c", column[i], ' ');
                        }
                        if (n == maxn / 2) { /* internal branch */
                                for (i = 0, lim = column[depth] - 3; i < lim; i++)
                                        fputc(bch, outfp);
                                if (num < 10)
                                        fprintf(outfp, "--%d", num);
                                else if (num < 100)
                                        fprintf(outfp, "-%2d", num);
                                else
                                        fprintf(outfp, "%3d", num);
                        } else {
                                if (umbrella[depth])
                                        fprintf(outfp, "%*c", column[depth], ':');
                                else
                                        fprintf(outfp, "%*c", column[depth], ' ');
                        }
                        fputc('\n', outfp);
                        fputc(' ', outfp);
                }
                if (m == maxm) umbrella[depth - 1] = FALSE;
        }
        return;
}


void getproportion(double *proportion, dvector distanvec, int numspc)
{
        int i, maxpair;
        double maxdis;
        
        maxpair = (numspc*(numspc-1))/2;

        maxdis = 0.0;
        for (i = 0; i < maxpair; i++) {
                if (distanvec[i] > maxdis) {
                        maxdis = distanvec[i];
                }
        }
        *proportion = (double) MAXCOLUMN / (maxdis * 3.0);
        if (*proportion > 1.0) *proportion = 1.0;
}


void prtopology(FILE *outfp)
{
        int n, maxn, depth;
        ivector umbrella;
        ivector column;
        Node *cp, *rp;
        
        getproportion(&Proportion, Distanvec, Numspc);

        umbrella = new_ivector(Numspc);
        column = new_ivector(Numspc);

        for (n = 0; n < Numspc; n++) {
                umbrella[n] = FALSE;
                column[n] = 3;
        }
        column[0] = 1;
        
        fputc(' ', outfp);

        /* original code: rp = Ctree->rootp */
        /* but we want to print the first group in the 
           trichotomy as outgroup at the bottom! */
        rp = Ctree->rootp->isop;
        
        for (maxn = 1, cp = rp->isop; cp != rp; cp = cp->isop, maxn++)
                ;
        depth = 1;
        n = 0;

        cp = rp;
        do {
                cp = cp->isop;
                n++;
                prbranch(cp->kinp, depth, n, maxn, umbrella, column, outfp);
                if (cp != rp) fprintf(outfp, "%*c\n ", column[0], ':');
        } while (cp != rp);

        free_ivector(umbrella);
        free_ivector(column);
}


/* print unrooted tree file with branch lengths */
void fputphylogeny(FILE *fp)
{
        Node *cp, *rp;
        int n;

        cp = rp = Ctree->rootp;
        putc('(', fp);
        n = 1;
        do {
                cp = cp->isop->kinp;
                if (cp->isop == NULL) { /* external node */
                        if (n > 60) {
                                fprintf(fp, "\n");
                                n = 2;
                        }
                        n += fputid(fp, cp->number);
                        fprintf(fp, ":%.5f", ((clockmode ? cp->lengthc : cp->length))*0.01);
                        n += 7;
                        cp = cp->kinp;
                } else { /* internal node */
                        if (cp->descen) {
                                if (n > 60) {
                                        fprintf(fp, "\n");
                                        n = 1;
                                }
                                putc('(', fp);
                                n++;
                        } else {
                                putc(')', fp);
                                n++;
                                if (n > 60) {
                                        fprintf(fp, "\n");
                                        n = 1;
                                }
                                /* internal label */
                                if (cp->kinp->label != NULL) {
                                        fprintf(fp, "%s", cp->kinp->label);
                                        n += strlen(cp->kinp->label);
                                }
                                fprintf(fp, ":%.5f", ((clockmode ? cp->lengthc : cp->length))*0.01);
                                n += 7;
                        }
                }
                if (!cp->descen && !cp->isop->descen && cp != rp) {
                        putc(',', fp); /* not last subtree */
                        n++;
                }
        } while (cp != rp);
        fprintf(fp, ")");
        /* internal label */
        if (cp->label != NULL)
                fprintf(fp, "%s", cp->label);
        fprintf(fp, ";\n");
}


void resulttree(FILE *outfp)
{
        int n, ne, closeflag;
        Node *ep, *ip;
        double blen;
        
        closeflag = FALSE;
        
        if (clockmode) {
                fprintf(outfp, "\n         branch  length     nc/c");
                fprintf(outfp, "   branch  length     nc/c (= non-clock/clock)\n");
        } else {
                fprintf(outfp, "\n         branch  length     S.E.");
                fprintf(outfp, "   branch  length     S.E.\n");
        }
        for (n = 0; n < Numspc; n++) {
                ep = Ctree->ebrnchp[n];
                ne = ep->number;
                fputid10(outfp, ne);
                fputs("  ", outfp);
                fprintf(outfp, "%3d", ne + 1);
                blen = (clockmode ? ep->lengthc : ep->length);
                fprintf(outfp, "%9.5f", blen*0.01);
                if (blen < 5.0*MINARC || blen > 0.95*MAXARC) closeflag = TRUE;
                if (clockmode)
                        fprintf(outfp, "%9.3f", (ep->length)/(ep->lengthc));
                else
                        fprintf(outfp, "%9.5f", 0.01*sqrt(ep->kinp->varlen));   
                if (n < Numibrnch) {
                        ip = Ctree->ibrnchp[n];
                        fprintf(outfp, "%8d", n + 1 + Numspc);
                        blen = (clockmode ? ip->lengthc : ip->length);
                        fprintf(outfp, "%9.5f", blen*0.01);
                        if (blen < 5.0*MINARC || blen > 0.95*MAXARC) closeflag = TRUE;
                        if (clockmode)
                                fprintf(outfp, "%9.3f", (ip->length)/(ip->lengthc));
                        else
                                fprintf(outfp, "%9.5f", 0.01*sqrt(ip->kinp->varlen));   
                        fputc('\n', outfp);
                } else {
                        if (n == Numspc - 3) {
                                fputc('\n', outfp);
                        } else if (n == Numspc - 2) {
                                if (clockmode) {
                                        if (!Convergc) 
                                                fprintf(outfp, "     No convergence after %d iterations!\n", Numitc);
                                        else
                                                fprintf(outfp, "     %d iterations until convergence\n", Numitc);
                                } else {
                                        if (!Converg) 
                                                fprintf(outfp, "     No convergence after %d iterations!\n", Numit);
                                        else
                                                fprintf(outfp, "     %d iterations until convergence\n", Numit);                                
                                }               
                        } else if (n == Numspc - 1) {
                                fprintf(outfp, "     log L: %.2f\n", (clockmode ? Ctree->lklhdc : Ctree->lklhd));
                        } else {
                                fputc('\n', outfp);
                        }
                }
        }
        if(closeflag)
                fprintf(outfp, "\nWARNING --- at least one branch length is close to an internal boundary!\n");
}


/******************************************************************************/
/* Neighbor-joining tree                                                      */
/******************************************************************************/


/* compute NJ tree and write to file */
void njtree(FILE *fp)
{
        /* reserve memory for tree if necessary */
        if (mlmode != 3) { /* no tree */
                if (Ctree != NULL)
                        free_tree(Ctree, Numspc);
                Ctree = new_tree(Maxspc, Numptrn, Seqpat);
                Numbrnch = 2*Maxspc-3;
                Numibrnch = Maxspc-3;
                Numspc = Maxspc;
                mlmode = 3;
        }

        /* construct NJ tree from distance matrix */
        njdistantree(Ctree);
        
        fputphylogeny(fp);
}


/* construct  NJ tree from distance matrix */
void njdistantree(Tree *tr)
{
        int i, j, otui=0, otuj=0, otuk, nsp2, cinode, step, restsp, k;
        double dij, bix, bjx, bkx, sij, smax, dnsp2;
        dvector r;
        dmatrix distan;
        Node **psotu, *cp, *ip, *jp, *kp;

        distan = new_dmatrix(Maxspc,Maxspc);
        for (i = 0; i < Maxspc; i++)
                for (j = 0; j < Maxspc; j++)
                        distan[i][j] = Distanmat[i][j];

        nsp2 = Maxspc - 2;
        dnsp2 = 1.0 / nsp2;
        
        r = new_dvector(Maxspc);
        
        psotu = (Node **) malloc((unsigned)Maxspc * sizeof(Node *));
        if (psotu == NULL) maerror("psotu in njdistantree");

        /* external branches are start OTUs */
        for (i = 0; i < Maxspc; i++)
                psotu[i] = tr->ebrnchp[i]->kinp;
        
        restsp = Maxspc;
        cinode = 0; /* counter for internal nodes */
        
        for (step = 0; restsp > 3; step++) { /* NJ clustering steps */
        
                for (i = 0; i < Maxspc; i++) {
                        if (psotu[i] != NULL) {
                                for (j = 0, r[i] = 0.0; j < Maxspc; j++)
                                        if (psotu[j] != NULL)
                                                r[i] += distan[i][j];
                        }
                }
                
                smax = -1.0;
                for (i = 0; i < Maxspc-1; i++) {
                        if (psotu[i] != NULL) {
                                
                                for (j = i+1; j < Maxspc; j++) {
                                        if (psotu[j] != NULL)
                                        {
                                                sij = ( r[i] + r[j] ) * dnsp2 - distan[i][j];
                        
                                                if (sij > smax) {
                                                        smax = sij;
                                                        otui = i;
                                                        otuj = j;
                                                }
                                        }
                                }
                        }
                }

                /* new pair: otui and otuj */

                dij = distan[otui][otuj];
                bix = (dij + r[otui]/nsp2 - r[otuj]/nsp2) * 0.5;
                bjx = dij - bix;
                
                cp = tr->ibrnchp[cinode];
                
                ip = psotu[otui];
                jp = psotu[otuj];
                cp->isop = ip;
                ip->isop = jp;
                jp->isop = cp;
                ip->length = bix;
                jp->length = bjx;
                ip->kinp->length = ip->length;
                jp->kinp->length = jp->length;
                
                cp = cp->kinp;
                
                for (k = 0; k < Maxspc; k++)
                {
                        if (psotu[k] != NULL && k != otui && k != otuj)
                        {
                                dij = (distan[otui][k] + distan[otuj][k] - distan[otui][otuj]) * 0.5;
                                distan[otui][k] = dij;
                                distan[k][otui] = dij;
                        }
                }
                distan[otui][otui] = 0.0;

                psotu[otui] = cp;
                psotu[otuj] = NULL;
                
                cinode++;
                
                restsp--;
                nsp2--;
                dnsp2 = 1.0 / nsp2;
        }
 
        otui = otuj = otuk = -1;
        for (i = 0; i < Maxspc; i++)
        {
                if (psotu[i] != NULL) {
                        if (otui == -1) otui = i;
                        else if (otuj == -1) otuj = i;
                        else otuk = i;
                }
        }
        bix = (distan[otui][otuj] + distan[otui][otuk] - distan[otuj][otuk]) * 0.5;
        bjx = distan[otui][otuj] - bix;
        bkx = distan[otui][otuk] - bix;
        ip = psotu[otui];
        jp = psotu[otuj];
        kp = psotu[otuk];
        ip->isop = jp;
        jp->isop = kp;
        kp->isop = ip;
        ip->length = bix;
        jp->length = bjx;
        kp->length = bkx;
        ip->kinp->length = ip->length;
        jp->kinp->length = jp->length;
        kp->kinp->length = kp->length;

        tr->rootp = kp;

        free_dvector(r);
        free_dmatrix(distan);
        free((Node *) psotu);
}

/******************************************************************************/
/* find best assignment of rate categories                                    */
/******************************************************************************/

/* find best assignment of rate categories */
void findbestratecombination()
{
        int k, u;
        double bestvalue, fv2;
        dvector catprob;
        dmatrix cdl;

        cdl = Ctree->condlkl;
        catprob = new_dvector(numcats+1);
        fv2 = (1.0-fracinv)/(double) numcats;

        for (k = 0; k < Numptrn; k++) {
                /* zero rate */
                if (constpat[k] == TRUE)
                        catprob[0] = fracinv*Freqtpm[(int) Seqpat[0][k]];
                else 
                        catprob[0] = 0.0;
                /* non-zero-rates */
                for (u = 1; u < numcats+1; u++)
                        catprob[u] = fv2*cdl[u-1][k];
                /* find best */
                bestvalue = catprob[0];
                bestrate[k] = 0;
                for (u = 1; u < numcats+1; u++)
                        if (catprob[u] >= bestvalue) {
                                bestvalue = catprob[u];
                                bestrate[k] = u;
                        }
        }
        free_dvector(catprob);
        bestratefound = 1;
}

/* print best assignment of rate categories */
void printbestratecombination(FILE *fp)
{
        int s, k;

        for (s = 0; s < Maxsite; s++) {
                k = Alias[s];
                fprintf(fp, "%2d", bestrate[k]);
                if ((s+1) % 30 == 0)
                        fprintf(fp, "\n");
                else if ((s+1) % 10 == 0)
                        fprintf(fp, "  ");
        }
        if (s % 70 != 0)
                fprintf(fp, "\n");
}


/******************************************************************************/
/* computation of clocklike branch lengths                                    */
/******************************************************************************/

/* checks wether e is a valid edge specification */
int checkedge(int e)
{
        /* there are Numspc external branches:
             0 - Numspc-1
           there are Numibrnch internal branches:
             Numspc - Numspc+Numibrnch-1
        */
        
        if (e < 0) return FALSE;
        if (e < Numspc+Numibrnch) return TRUE;
        else return FALSE;  
}

/* print topology of subtree */
void fputsubstree(FILE *fp, Node *ip)
{
        Node *cp;
        
        if (ip->isop == NULL) { /* terminal nodes */
                numtc += fputid(fp, ip->number);
        } else {        
                cp = ip;
                fprintf(fp, "(");
                numtc += 1;
                do {            
                        cp = cp->isop->kinp;
                        if (cp->isop == NULL) { /* external node */
                                numtc += fputid(fp, cp->number);
                                fprintf(fp, ":%.5f", (cp->lengthc)*0.01);
                                numtc += 7;
                                cp = cp->kinp;
                        } else { /* internal node */
                                if (cp->height > 0.0) {
                                        fprintf(fp, "(");
                                        numtc += 1;
                                } else if (cp->height < 0.0) {
                                        fprintf(fp, ")");
                                        numtc += 1;
                                        if (numtc > 60) {
                                                fprintf(fp, "\n");
                                                numtc = 1;
                                        }
                                        /* internal label */
                                        if (cp->kinp->label != NULL) {
                                                fprintf(fp, "%s", cp->kinp->label);
                                                numtc += strlen(cp->kinp->label);
                                        }
                                        if (numtc > 60) {
                                                fprintf(fp, "\n");
                                                numtc = 1;
                                        }
                                        fprintf(fp, ":%.5f", (cp->lengthc)*0.01);
                                        numtc += 6;
                                        if (numtc > 60) {
                                                fprintf(fp, "\n");
                                                numtc = 1;
                                        }
                                }
                        }
                        if (cp->height <= 0.0 && cp->isop->height <= 0.0 &&
                                cp->isop != ip) {
                                putc(',', fp); /* not last subtree */
                                numtc += 1;
                                if (numtc > 60) {
                                        fprintf(fp, "\n");
                                        numtc = 1;
                                }
                        }
                } while (cp->isop != ip);
                fprintf(fp, ")");
                numtc += 1;
        }
        if (numtc > 60) {
                fprintf(fp, "\n");
                numtc = 1;
        }

}

/* print rooted tree file  */
void fputrooted(FILE *fp, int e)
{
        Node *rootbr;
        
        /* to be called only after clocklike branch
           lengths have been computed */
         
         /* pointer to root branch */
        if (e < Numspc) rootbr = Ctree->ebrnchp[e];
        else rootbr = Ctree->ibrnchp[e - Numspc];

        fprintf(fp, "(");
        numtc = 2;
        fputsubstree(fp, rootbr);
        /* internal label */
        if (rootbr->label != NULL) {
                fprintf(fp, "%s", rootbr->label);
                numtc += strlen(rootbr->label);
        }
        if (numtc > 60) {
                fprintf(fp, "\n");
                numtc = 1;
        }
        fprintf(fp, ":%.5f,", (hroot - rootbr->height)*0.01);
        numtc += 7;
        if (numtc > 60) {
                fprintf(fp, "\n");
                numtc = 1;
        }
        fputsubstree(fp, rootbr->kinp);
        /* internal label */
        if (rootbr->kinp->label != NULL) {
                fprintf(fp, "%s", rootbr->kinp->label);
                numtc += strlen(rootbr->kinp->label);
        }
        if (numtc > 60) {
                fprintf(fp, "\n");
                numtc = 1;
        }
        fprintf(fp, ":%.5f);\n", (hroot - rootbr->kinp->height)*0.01);
}

/* finds heights in subtree */
void findheights(Node *ip)
{
        Node *cp, *rp;
        
        if (ip->isop != NULL) { /* forget terminal nodes */
                
                cp = ip;
                
                /* initialise node  */
                cp->height = 1.0; /* up */
                rp = cp;
                while (rp->isop != cp) {
                        rp = rp->isop;
                        rp->height = -1.0; /* down */
                }

                do {            
                        cp = cp->isop->kinp;
                        if (cp->isop == NULL) { /* external node */
                                cp = cp->kinp;
                        } else { /* internal node */
                                if (cp->height == 0.0) { /* node not yet visited */
                                        cp->height = 1.0; /* up */
                                        rp = cp;
                                        while (rp->isop != cp) {
                                                rp = rp->isop;
                                                rp->height = -1.0; /* down */
                                        }
                                } else if (cp->kinp->height == 1.0) {
                                        /* cp->kinp is next height pointer  */
                                        heights[Numhts] = cp->kinp;
                                        Numhts++;
                                }
                        }
                } while (cp->isop != ip);
                /* ip is last height pointer */
                heights[Numhts] = ip;
                Numhts++;
        }       
}


/* initialise clocklike branch lengths (with root on edge e) */
void initclock(int e)
{
        int n, h, count;
        Node *cp, *rp;
        double sum, minh, aveh, len;

        /* be sure to have a Ctree in memory and
           to have pairwise distances computed */

        clockmode = 1; /* clocklike branch lengths */

        /* least square estimate for branch length */
        changedistan(Distanmat, Distanvec, Numspc);
        lslength(Ctree, Distanvec, Numspc, Numibrnch, Brnlength);

        /* pointer to root branch */
        if (e < Numspc) rootbr = Ctree->ebrnchp[e];
        else rootbr = Ctree->ibrnchp[e - Numspc];
           
        /* clear all heights */
        for (n = 0; n < Numspc; n++) {
                Ctree->ebrnchp[n]->height = 0.0;
                Ctree->ebrnchp[n]->kinp->height = 0.0;
                Ctree->ebrnchp[n]->varheight = 0.0;
                Ctree->ebrnchp[n]->kinp->varheight = 0.0;
                if (n < Numibrnch) {
                        Ctree->ibrnchp[n]->height = 0.0;
                        Ctree->ibrnchp[n]->kinp->height = 0.0;
                        Ctree->ibrnchp[n]->varheight = 0.0;
                        Ctree->ibrnchp[n]->kinp->varheight = 0.0;
                }
        }
        
        /* collect pointers to height nodes */
        Numhts = 0;
        findheights(rootbr); /* one side */
        findheights(rootbr->kinp); /* other side */

        /* assign preliminary approximate heights and
           corresponding branch lengths */ 
        for (h = 0; h < Numhts; h++) {
                
                cp = rp = heights[h];
                sum = 0;
                count = 0;
                minh = 0.0;
                while (rp->isop != cp) {
                        count++;
                        rp = rp->isop;
                        sum += rp->lengthc + rp->kinp->height;
                        if (rp->kinp->height > minh) minh = rp->kinp->height;
                }
                aveh = sum / (double) count;
                if (aveh < minh + MINARC) aveh = minh + MINARC;
                cp->height = aveh;
                rp = cp;
                while (rp->isop != cp) {
                        rp = rp->isop;
                        len = aveh - rp->kinp->height;
                        rp->kinp->lengthc = len;
                        rp->lengthc = len;
                }
                
        }
        if (rootbr->height > rootbr->kinp->height) minh = rootbr->height;
        else minh = rootbr->kinp->height;
        aveh = 0.5*(rootbr->lengthc + rootbr->height + rootbr->kinp->height);
        if (aveh < minh + MINARC) aveh = minh + MINARC; 
        hroot = aveh;
        maxhroot = RMHROOT*hroot; /* maximal possible hroot */
        len = (hroot - rootbr->height) + (hroot - rootbr->kinp->height);
        rootbr->lengthc = len;
        rootbr->kinp->lengthc = len;
}

/* approximate likelihood under the constaining assumption of
   clocklike branch lengths (with root on edge e) */
double clock_alklhd(int e)
{
        initclock(e);
        Ctree->lklhdc = treelkl(Ctree);

        return Ctree->lklhdc;   
}

/* log-likelihood given height ht at node pointed to by chep */
double heightlkl(double ht)
{
        Node *rp;
        double len;     
        
        /* adjust branch lengths */
        chep->height = ht;
        /* descendent branches */
        rp = chep;
        while (rp->isop != chep) {
                rp = rp->isop;
                len = chep->height - rp->kinp->height;
                rp->kinp->lengthc = len;
                rp->lengthc = len;
        }
        /* upward branch */
        if (chep == rootbr || chep->kinp == rootbr) {
                len = (hroot - chep->height) + (hroot - chep->kinp->height);
                chep->lengthc = len;
                chep->kinp->lengthc = len;
        } else {
                rp = chep->kinp;
                while (rp->isop->height <= 0.0)
                        rp = rp->isop;
                chep->lengthc = rp->isop->height - chep->height;
                chep->kinp->lengthc = rp->isop->height - chep->height;
        }

        /* compute likelihood */
        Ctree->lklhdc = treelkl(Ctree);

        return -(Ctree->lklhdc); /* we use a minimizing procedure */
}

/* optimize current height */
void optheight(void)
{
        double he, fx, f2x, minh, maxh, len;
        Node *rp;

        /* current height */
        he = chep->height;
        
        /* minimum */
        minh = 0.0;
        rp = chep;
        while (rp->isop != chep) {
                rp = rp->isop;
                if (rp->kinp->height > minh)
                        minh = rp->kinp->height;
        }
        minh += MINARC;
        
        /* maximum */
        if (chep == rootbr || chep->kinp == rootbr) {
                maxh = hroot;
        } else {
                rp = chep->kinp;
                while (rp->isop->height <= 0.0)
                        rp = rp->isop;
                maxh = rp->isop->height;
        }
        maxh -= MINARC;

        /* check borders for height */
        if (he < minh) he = minh;
        if (he > maxh) he = maxh;

        /* optimization */
        if (!(he == minh && he == maxh))
                he = onedimenmin(minh, he, maxh, heightlkl, HEPSILON, &fx, &f2x);
        
        /* variance of height */
        f2x = fabs(f2x);
        if (1.0/(maxhroot*maxhroot) < f2x)
                chep->varheight = 1.0/f2x;
        else
                chep->varheight = maxhroot*maxhroot;
        
        /* adjust branch lengths */
        chep->height = he;
        /* descendent branches */
        rp = chep;
        while (rp->isop != chep) {
                rp = rp->isop;
                len = chep->height - rp->kinp->height;
                rp->kinp->lengthc = len;
                rp->lengthc = len;
        }
        /* upward branch */
        if (chep == rootbr || chep->kinp == rootbr) {
                len = (hroot - chep->height) + (hroot - chep->kinp->height);
                chep->lengthc = len;
                chep->kinp->lengthc = len;
        } else {
                rp = chep->kinp;
                while (rp->isop->height <= 0.0)
                        rp = rp->isop;
                chep->lengthc = rp->isop->height - chep->height;
                chep->kinp->lengthc = rp->isop->height - chep->height;
        }
}

/* log-likelihood given height ht at root */
double rheightlkl(double ht)
{
        double len;     
        
        /* adjust branch lengths */
        hroot = ht;
        len = (hroot - rootbr->height) + (hroot - rootbr->kinp->height);
        rootbr->lengthc = len;
        rootbr->kinp->lengthc = len;

        /* compute likelihood */
        Ctree->lklhdc = treelkl(Ctree);

        return -(Ctree->lklhdc); /* we use a minimizing procedure */
}

/* optimize height of root */
void optrheight(void)
{
        double he, fx, f2x, minh, len;

        /* current height */
        he = hroot;
        
        /* minimum */
        if (rootbr->height > rootbr->kinp->height)
                minh = rootbr->height;
        else
                minh = rootbr->kinp->height;
        minh += MINARC;
                
        /* check borders for height */
        if (he < minh) he = minh;
        if (he > maxhroot) he = maxhroot;

        /* optimization */
        he = onedimenmin(minh, he, maxhroot, rheightlkl, HEPSILON, &fx, &f2x);
        
        /* variance of height of root */
        f2x = fabs(f2x);
        if (1.0/(maxhroot*maxhroot) < f2x)
                varhroot = 1.0/f2x;
        else
                varhroot = maxhroot*maxhroot;

        /* adjust branch lengths */
        hroot = he;
        len = (hroot - rootbr->height) + (hroot - rootbr->kinp->height);
        rootbr->lengthc = len;
        rootbr->kinp->lengthc = len;
}

/* exact likelihood under the constaining assumption of
   clocklike branch lengths (with root on edge e) */
double clock_lklhd(int e)
{
        int h, nconv;
        double old;
        
        Numitc = 0;
        Convergc = FALSE;
        
        initclock(e);
        
        do {
        
                Numitc++;
                nconv = 0;

                /* optimize height of root */
                old = hroot;
                optrheight();
                if (fabs(old - hroot) < HEPSILON) nconv++;

                /* optimize height of nodes */
                for (h = Numhts-1; h >= 0; h--) {
                
                        /* pointer chep to current height node */
                        chep = heights[h];
                        
                        /* store old value */
                        old = chep->height;

                        /* find better height */
                        optheight();
                        
                        /* converged ? */
                        if (fabs(old - chep->height) < HEPSILON) nconv++;
                }

                if (nconv == Numhts+1) Convergc = TRUE;
                        
        } while (Numitc < MAXIT && !Convergc);
                
        /* compute final likelihood */
        Ctree->lklhdc = treelkl(Ctree);

        return Ctree->lklhdc;
}

/* find out the edge containing the root */
int findrootedge()
{
        int e, ebest;
        double logbest, logtest;
        
        /* compute the likelihood for all edges and take the edge with
           best likelihood (using approximate ML) */

        ebest = 0;
        logbest = clock_alklhd(0);
        numbestroot = 1;
        for (e = 1; e < Numspc+Numibrnch; e++) {
                logtest = clock_alklhd(e);
                if (logtest > logbest) {
                        ebest = e;
                        logbest = logtest;
                        numbestroot = 1;
                } else if (logtest == logbest) {
                        numbestroot++;
                }
        }

        return ebest;
}

/* show heights and corresponding standard errors */
void resultheights(FILE *fp)
{
        int h, num;
        Node *cp;
        
        fprintf(fp, " height    S.E.    of node common to branches\n");
        for (h = 0; h < Numhts; h++) {
                fprintf(fp, "%.5f  %.5f    ", (heights[h]->height)*0.01,
                        sqrt(heights[h]->varheight)*0.01);
                cp = heights[h];
                do {
                        num = (cp->number) + 1;
                        if (cp->kinp->isop != NULL) num += Numspc; /* internal branch */                        
                        fprintf(fp, "%d  ", num);
                        cp = cp->isop;
                } while (cp != heights[h]);     
                fprintf(fp, "\n");
                
        }
        fprintf(fp, "%.5f  %.5f   of root at branch %d\n",
                hroot*0.01, sqrt(varhroot)*0.01, locroot+1);
}