.TH "dstev.f" 3 "Wed Oct 15 2014" "Version 3.4.2" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME dstev.f \- .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBdstev\fP (JOBZ, N, D, E, Z, LDZ, WORK, INFO)" .br .RI "\fI\fB DSTEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for OTHER matrices\fP \fP" .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine dstev (characterJOBZ, integerN, double precision, dimension( * )D, double precision, dimension( * )E, double precision, dimension( ldz, * )Z, integerLDZ, double precision, dimension( * )WORK, integerINFO)" .PP \fB DSTEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for OTHER matrices\fP .PP \fBPurpose: \fP .RS 4 .PP .nf DSTEV computes all eigenvalues and, optionally, eigenvectors of a real symmetric tridiagonal matrix A. .fi .PP .RE .PP \fBParameters:\fP .RS 4 \fIJOBZ\fP .PP .nf JOBZ is CHARACTER*1 = 'N': Compute eigenvalues only; = 'V': Compute eigenvalues and eigenvectors. .fi .PP .br \fIN\fP .PP .nf N is INTEGER The order of the matrix. N >= 0. .fi .PP .br \fID\fP .PP .nf D is DOUBLE PRECISION array, dimension (N) On entry, the n diagonal elements of the tridiagonal matrix A. On exit, if INFO = 0, the eigenvalues in ascending order. .fi .PP .br \fIE\fP .PP .nf E is DOUBLE PRECISION array, dimension (N-1) On entry, the (n-1) subdiagonal elements of the tridiagonal matrix A, stored in elements 1 to N-1 of E. On exit, the contents of E are destroyed. .fi .PP .br \fIZ\fP .PP .nf Z is DOUBLE PRECISION array, dimension (LDZ, N) If JOBZ = 'V', then if INFO = 0, Z contains the orthonormal eigenvectors of the matrix A, with the i-th column of Z holding the eigenvector associated with D(i). If JOBZ = 'N', then Z is not referenced. .fi .PP .br \fILDZ\fP .PP .nf LDZ is INTEGER The leading dimension of the array Z. LDZ >= 1, and if JOBZ = 'V', LDZ >= max(1,N). .fi .PP .br \fIWORK\fP .PP .nf WORK is DOUBLE PRECISION array, dimension (max(1,2*N-2)) If JOBZ = 'N', WORK is not referenced. .fi .PP .br \fIINFO\fP .PP .nf INFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value > 0: if INFO = i, the algorithm failed to converge; i off-diagonal elements of E did not converge to zero. .fi .PP .RE .PP \fBAuthor:\fP .RS 4 Univ\&. of Tennessee .PP Univ\&. of California Berkeley .PP Univ\&. of Colorado Denver .PP NAG Ltd\&. .RE .PP \fBDate:\fP .RS 4 November 2011 .RE .PP .PP Definition at line 117 of file dstev\&.f\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.