_RST(3F)_RST(3F)NAME
RST, SRST - EISPACK routine. This subroutine calls the recommended
sequence of subroutines from the eigensystem subroutine package (EISPACK)
to find the eigenvalues and eigenvectors (if desired) of a REAL SYMMETRIC
TRIDIAGONAL matrix.
SYNOPSYS
subroutine rst(nm, n, w, e, matz, z, ierr)
integer nm, n, matz, ierr
double precision w(n), e(n), z(nm,n)
subroutine srst(nm, n, w, e, matz, z, ierr)
integer nm, n, matz, ierr
real w(n), e(n), z(nm,n)
DESCRIPTION
On Input
NM must be set to the row dimension of the two-dimensional array
parameters as declared in the calling program dimension statement.
N is the order of the matrix.
W contains the diagonal elements of the real symmetric tridiagonal
matrix.
E contains the subdiagonal elements of the matrix in its last N-1
POSITIONS. E(1) is arbitrary.
MATZ is an integer variable set equal to zero if only eigenvalues are
desired. Otherwise it is set to any non-zero integer for both
eigenvalues and eigenvectors. On Output
W contains the eigenvalues in ascending order.
Z contains the eigenvectors if MATZ is not zero.
IERR is an integer output variable set equal to an error completion code
described in section 2B of the documentation. The normal completion code
is zero. Questions and comments should be directed to B. S. Garbow,
APPLIED MATHEMATICS DIVISION, ARGONNE NATIONAL LABORATORY
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