RG calls the recommended sequence of EISPACK subroutines to
find the eigenvalues and, if desired, the eigenvectors of a
real, general matrix.
- Input, INTEGER NM, the row dimension (first dimension) of the two
dimensional arrays as declared in the calling program.
- Input, INTEGER N, the order (=size=number of rows=number of columns)
of the matrix whose eigenvalues are sought.
- Input/output, REAL A(NM,N), on input, the matrix, which is overwritten
- Output, REAL WR(N), the real parts of the eigenvalues.
- Output, REAL WI(N), the imaginary parts of the eigenvalues.
- Input, INTEGER MATZ, set to 0 if only eigenvalues are desired.
Otherwise all eigenvectors will also be calculated.
- 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.
- Work vector, INTEGER IV1(N).
- Work vector, REAL FV1(N).
- Output, INTEGER IERR, an error flag. 0 if no errors, or
J if eigenvalues 1 through J were not found.
© Pittsburgh Supercomputing Center (PSC)
Revised: October 1996