source: branches/help/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>
<!-- STANDARD PSC FOOTER OPENING -->
<hr>
<a href="http://www.psc.edu/general/software/software.html"><img alt="[Software]" src="http://www.psc.edu/general/images/icons/software_button.gif"></a>
<a href="http://www.psc.edu/"><img alt="[PSC Home Page]" src="http://www.psc.edu/general/images/icons/psc_home.gif"></a>
<a href="http://www.psc.edu/search/search.html"><img src="http://www.psc.edu/general/images/icons/search.gif"  alt="[Search]"></a> 
<a href="http://www.psc.edu/general/help/assistance.html"><img src="http://www.psc.edu/general/images/icons/help.gif"  alt="[Help]"></a> 
<a href="http://www.psc.edu/general/feedback.html"><img src="http://www.psc.edu/general/images/icons/feedback.gif" alt="[Feedback]"></a>
<hr>
<font size=-1>
<i><a href=/copyright.html>&#169;</a> Pittsburgh Supercomputing Center (PSC)<br>
Revised: October 1996 <br>
</i></font>
<font size=-2>
<i>URL: http://www.psc.edu/general/software/packages/eispack/subroutines/rg.html</i>
</font>
<!-- STANDARD PSC FOOTER CLOSING -->