subroutine cg(nm,n,ar,ai,wr,wi,matz,zr,zi,fv1,fv2,fv3,ierr) c integer n,nm,is1,is2,ierr,matz real ar(nm,n),ai(nm,n),wr(n),wi(n),zr(nm,n),zi(nm,n), x fv1(n),fv2(n),fv3(n) c c this subroutine calls the recommended sequence of c subroutines from the eigensystem subroutine package (eispack) c to find the eigenvalues and eigenvectors (if desired) c of a complex general matrix. c c on input c c nm must be set to the row dimension of the two-dimensional c array parameters as declared in the calling program c dimension statement. c c n is the order of the matrix a=(ar,ai). c c ar and ai contain the real and imaginary parts, c respectively, of the complex general matrix. c c matz is an integer variable set equal to zero if c only eigenvalues are desired. otherwise it is set to c any non-zero integer for both eigenvalues and eigenvectors. c c on output c c wr and wi contain the real and imaginary parts, c respectively, of the eigenvalues. c c zr and zi contain the real and imaginary parts, c respectively, of the eigenvectors if matz is not zero. c c ierr is an integer output variable set equal to an error c completion code described in the documentation for comqr c and comqr2. the normal completion code is zero. c c fv1, fv2, and fv3 are temporary storage arrays. c c questions and comments should be directed to burton s. garbow, c mathematics and computer science div, argonne national laboratory c c this version dated august 1983. c c ------------------------------------------------------------------ c if (n .le. nm) go to 10 ierr = 10 * n go to 50 c 10 call cbal(nm,n,ar,ai,is1,is2,fv1) call corth(nm,n,is1,is2,ar,ai,fv2,fv3) if (matz .ne. 0) go to 20 c .......... find eigenvalues only .......... call comqr(nm,n,is1,is2,ar,ai,wr,wi,ierr) go to 50 c .......... find both eigenvalues and eigenvectors .......... 20 call comqr2(nm,n,is1,is2,fv2,fv3,ar,ai,wr,wi,zr,zi,ierr) if (ierr .ne. 0) go to 50 call cbabk2(nm,n,is1,is2,fv1,n,zr,zi) 50 return end