Previous: zposvx Up: ../lapack-z.html Next: zpotrf
NAME ZPOTF2 - compute the Cholesky factorization of a complex Hermitian positive definite matrix A SYNOPSIS SUBROUTINE ZPOTF2( UPLO, N, A, LDA, INFO ) CHARACTER UPLO INTEGER INFO, LDA, N COMPLEX*16 A( LDA, * ) PURPOSE ZPOTF2 computes the Cholesky factorization of a complex Her- mitian positive definite matrix A. The factorization has the form A = U' * U , if UPLO = 'U', or A = L * L', if UPLO = 'L', where U is an upper triangular matrix and L is lower tri- angular. This is the unblocked version of the algorithm, calling Level 2 BLAS. ARGUMENTS UPLO (input) CHARACTER*1 Specifies whether the upper or lower triangular part of the Hermitian matrix A is stored. = 'U': Upper triangular = 'L': Lower triangular N (input) INTEGER The order of the matrix A. N >= 0. A (input/output) COMPLEX*16 array, dimension (LDA,N) On entry, the Hermitian matrix A. If UPLO = 'U', the leading n by n upper triangular part of A con- tains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If UPLO = 'L', the leading n by n lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper tri- angular part of A is not referenced. On exit, if INFO = 0, the factor U or L from the Cholesky factorization A = U'*U or A = L*L'. LDA (input) INTEGER The leading dimension of the array A. LDA >= max(1,N). INFO (output) INTEGER = 0: successful exit < 0: if INFO = -k, the k-th argument had an illegal value > 0: if INFO = k, the leading minor of order k is not positive definite, and the factorization could not be completed.