ZPSTF2(3)

🌸 NAME 🌸

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/zpstf2.f

okay bestie, welcome to the zpstf2.f(3) page from the Library Functions Manual — the NAME entry is literally that absolute source path above, no extra plot twists. 💅

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

• subroutine ZPSTF2 (uplo, n, a, lda, piv, rank, tol, work, info) — ZPSTF2 computes the Cholesky factorization with complete pivoting of a complex Hermitian positive semidefinite matrix.

💖 Function/Subroutine Documentation 💖

🌸 subroutine ZPSTF2 🌸

subroutine ZPSTF2 (character uplo, integer n, complex*16, dimension( lda, * ) a, integer lda, integer, dimension( n ) piv, integer rank, double precision tol, double precision, dimension( 2*n ) work, integer info)

ZPSTF2 computes the Cholesky factorization with complete pivoting of a complex Hermitian positive semidefinite matrix. 🫶

🎀 Purpose 🎀

Okay so ZPSTF2 computes the Cholesky factorization with complete pivoting of a complex Hermitian positive semidefinite matrix A. The factorization has the form:

P**T * A * P = U**H * U ,  if UPLO = 'U',
P**T * A * P = L  * L**H,  if UPLO = 'L',

where U is an upper triangular matrix and L is lower triangular, and P is stored as vector PIV. 💜

Heads up, bestie: this algorithm does not attempt to check that A is positive semidefinite. This version of the algorithm calls level 2 BLAS. 💀

🍓 Parameters 🍓

• UPLO — UPLO is CHARACTER*1. Specifies whether the upper or lower triangular part of the symmetric matrix A is stored.
  • = 'U': Upper triangular
  • = 'L': Lower triangular
• N — N is INTEGER. The order of the matrix A. N >= 0.
• A — A is COMPLEX*16 array, dimension (LDA,N). On entry, the symmetric matrix A. If UPLO = 'U', 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 = 'L', 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 as above. iconic.

• PIV — PIV is INTEGER array, dimension (N). PIV is such that the nonzero entries are P( PIV(K), K ) = 1.
• RANK — RANK is INTEGER. The rank of A given by the number of steps the algorithm completed.
• TOL — TOL is DOUBLE PRECISION. User defined tolerance. If TOL < 0, then N*U*MAX( A( K,K ) ) will be used. The algorithm terminates at the (K-1)st step if the pivot <= TOL.
• LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N).
• WORK — WORK is DOUBLE PRECISION array, dimension (2*N). Work space.
• INFO — INFO is INTEGER.
  • < 0: If INFO = -K, the K-th argument had an illegal value,
  • = 0: algorithm completed successfully, and
  • > 0: the matrix A is either rank deficient with computed rank as returned in RANK, or is not positive semidefinite. See Section 7 of LAPACK Working Note #161 for further information.

👑 Author 👑

• Univ. of Tennessee
• Univ. of California Berkeley
• Univ. of Colorado Denver
• NAG Ltd.

Definition at line 141 of file zpstf2.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

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okay bestie, that's the whole page 💖 This footer moment is LAPACK Version 3.12.0, source /home/abui...RC/zpstf2.f(3), and there’s no separate date printed with it — that’s the tea. Auto-generated by Doxygen for LAPACK from the source code. Stay slay, and may your pivots always be iconic. 👑✨