source: branches/port5/EISPACK/rg.html

<title>RG</title>
<h2>SUBROUTINE RG(NM,N,A,WR,WI,MATZ,Z,IV1,FV1,IERR)</h2>
 
RG calls the recommended sequence of EISPACK subroutines to
find the eigenvalues and, if desired, the eigenvectors of a
real, general matrix.
<p>
<dl>
<p><dt><b>NM</b>     
<dd>Input, INTEGER NM, the row dimension (first dimension) of the two
       dimensional arrays as declared in the calling program.
 
<p><dt><b>N</b>      
<dd>Input, INTEGER N, the order (=size=number of rows=number of columns)
       of the matrix whose eigenvalues are sought.
 
<p><dt><b>A</b>      
<dd>Input/output, REAL A(NM,N), on input, the matrix, which is overwritten
       on output.
 
<p><dt><b>WR</b>     
<dd>Output, REAL WR(N), the real parts of the eigenvalues.
 
<p><dt><b>WI</b>     
<dd>Output, REAL WI(N), the imaginary parts of the eigenvalues.
 
<p><dt><b>MATZ</b>   
<dd>Input, INTEGER MATZ, set to 0 if only eigenvalues are desired.
       Otherwise all eigenvectors will also be calculated.
 
<p><dt><b>Z</b>      
<dd>Output, REAL Z(NM,N), if MATZ is not zero, Z contains the
       eigenvectors of A.  If the J-th eigenvalue is real, the
       J-th column of Z is its eigenvector.  If the J-th
       eigenvalue is complex with positive real part (then the
       J+1-th eigenvalue is its complex conjugate), its eigenvector
       has real part in the J-th column of Z and imaginary part
       in the J+1-th column of Z.
 
<p><dt><b>IV1</b>    
<dd>Work vector, INTEGER IV1(N).
 
<p><dt><b>FV1</b>    
<dd>Work vector, REAL FV1(N).
 
<p><dt><b>IERR</b>   
<dd>Output, INTEGER IERR, an error flag.  0 if no errors, or
       J if eigenvalues 1 through J were not found.
</dl>
<p>
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<i><a href=/copyright.html>&#169;</a> Pittsburgh Supercomputing Center (PSC)<br>
Revised: October 1996 <br>
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<i>URL: http://www.psc.edu/general/software/packages/eispack/subroutines/rg.html</i>
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