.TH "SRC/chpev.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME SRC/chpev.f .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBchpev\fP (jobz, uplo, n, ap, w, z, ldz, work, rwork, info)" .br .RI "\fB CHPEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for OTHER matrices\fP " .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine chpev (character jobz, character uplo, integer n, complex, dimension( * ) ap, real, dimension( * ) w, complex, dimension( ldz, * ) z, integer ldz, complex, dimension( * ) work, real, dimension( * ) rwork, integer info)" .PP \fB CHPEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for OTHER matrices\fP .PP \fBPurpose:\fP .RS 4 .PP .nf CHPEV computes all the eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix in packed storage\&. .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 \fIUPLO\fP .PP .nf UPLO is CHARACTER*1 = 'U': Upper triangle of A is stored; = 'L': Lower triangle of A is stored\&. .fi .PP .br \fIN\fP .PP .nf N is INTEGER The order of the matrix A\&. N >= 0\&. .fi .PP .br \fIAP\fP .PP .nf AP is COMPLEX array, dimension (N*(N+1)/2) On entry, the upper or lower triangle of the Hermitian matrix A, packed columnwise in a linear array\&. The j-th column of A is stored in the array AP as follows: if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = 'L', AP(i + (j-1)*(2*n-j)/2) = A(i,j) for j<=i<=n\&. On exit, AP is overwritten by values generated during the reduction to tridiagonal form\&. If UPLO = 'U', the diagonal and first superdiagonal of the tridiagonal matrix T overwrite the corresponding elements of A, and if UPLO = 'L', the diagonal and first subdiagonal of T overwrite the corresponding elements of A\&. .fi .PP .br \fIW\fP .PP .nf W is REAL array, dimension (N) If INFO = 0, the eigenvalues in ascending order\&. .fi .PP .br \fIZ\fP .PP .nf Z is COMPLEX 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 W(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 COMPLEX array, dimension (max(1, 2*N-1)) .fi .PP .br \fIRWORK\fP .PP .nf RWORK is REAL array, dimension (max(1, 3*N-2)) .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 an intermediate tridiagonal form 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 .PP Definition at line \fB136\fP of file \fBchpev\&.f\fP\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.