.TH ZPOTF2 1 "November 2006" " LAPACK routine (version 3.1) " " LAPACK routine (version 3.1) " .SH NAME ZPOTF2 - the Cholesky factorization of a complex Hermitian positive definite matrix A .SH SYNOPSIS .TP 19 SUBROUTINE ZPOTF2( UPLO, N, A, LDA, INFO ) .TP 19 .ti +4 CHARACTER UPLO .TP 19 .ti +4 INTEGER INFO, LDA, N .TP 19 .ti +4 COMPLEX*16 A( LDA, * ) .SH PURPOSE ZPOTF2 computes the Cholesky factorization of a complex Hermitian positive definite matrix A. The factorization has the form .br A = U\(aq * U , if UPLO = \(aqU\(aq, or .br A = L * L\(aq, if UPLO = \(aqL\(aq, .br where U is an upper triangular matrix and L is lower triangular. This is the unblocked version of the algorithm, calling Level 2 BLAS. .SH ARGUMENTS .TP 8 UPLO (input) CHARACTER*1 Specifies whether the upper or lower triangular part of the Hermitian matrix A is stored. = \(aqU\(aq: Upper triangular .br = \(aqL\(aq: Lower triangular .TP 8 N (input) INTEGER The order of the matrix A. N >= 0. .TP 8 A (input/output) COMPLEX*16 array, dimension (LDA,N) On entry, the Hermitian matrix A. If UPLO = \(aqU\(aq, the leading n by n upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If UPLO = \(aqL\(aq, the leading n by n lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced. On exit, if INFO = 0, the factor U or L from the Cholesky factorization A = U\(aq*U or A = L*L\(aq. .TP 8 LDA (input) INTEGER The leading dimension of the array A. LDA >= max(1,N). .TP 8 INFO (output) INTEGER = 0: successful exit .br < 0: if INFO = -k, the k-th argument had an illegal value .br > 0: if INFO = k, the leading minor of order k is not positive definite, and the factorization could not be completed.