subroutine rg(nm,n,a,wr,wi,matz,z,iv1,fv1,ierr) c integer n,nm,is1,is2,ierr,matz double precision a(nm,n),wr(n),wi(n),z(nm,n),fv1(n) integer iv1(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 real 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. c c a contains the real 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. complex conjugate c pairs of eigenvalues appear consecutively with the c eigenvalue having the positive imaginary part first. c c z contains the real and imaginary parts of the eigenvectors c if matz is not zero. if the j-th eigenvalue is real, the c j-th column of z contains its eigenvector. if the j-th c eigenvalue is complex with positive imaginary part, the c j-th and (j+1)-th columns of z contain the real and c imaginary parts of its eigenvector. the conjugate of this c vector is the eigenvector for the conjugate eigenvalue. c c ierr is an integer output variable set equal to an error c completion code described in the documentation for hqr c and hqr2. the normal completion code is zero. c c iv1 and fv1 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 balanc(nm,n,a,is1,is2,fv1) call elmhes(nm,n,is1,is2,a,iv1) if (matz .ne. 0) go to 20 c .......... find eigenvalues only .......... call hqr(nm,n,is1,is2,a,wr,wi,ierr) go to 50 c .......... find both eigenvalues and eigenvectors .......... 20 call eltran(nm,n,is1,is2,a,iv1,z) call hqr2(nm,n,is1,is2,a,wr,wi,z,ierr) if (ierr .ne. 0) go to 50 call balbak(nm,n,is1,is2,fv1,n,z) 50 return end