SRC/cpotrf.f(3)

🌸 NAME 🌸

SRC/cpotrf.f — okay bestie, this is the SRC/cpotrf.f(3) page from the Library Functions Manual, and it's all about the CPOTRF subroutine. 💅

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

• subroutine cpotrf (uplo, n, a, lda, info) — CPOTRF

subroutine cpotrf (character uplo, integer n, complex, dimension( lda, * )
       a, integer lda, integer info)

💖 Function/Subroutine Documentation 💖

Meet cpotrf, the main character of this page. The subroutine is declared as:

subroutine cpotrf (character uplo, integer n, complex, dimension( lda, * )
       a, integer lda, integer info)

And yes, this is CPOTRF. 👑

🎀 Purpose 🎀

CPOTRF computes the Cholesky factorization of a complex Hermitian positive definite matrix A. 🦋

The factorization has the form

A = U**H * U,  if UPLO = 'U', or
A = L  * L**H,  if UPLO = 'L',

where U is an upper triangular matrix and L is lower triangular. This is the block version of the algorithm, calling Level 3 BLAS. ✨

🫶 Parameters 🫶

UPLO

• UPLO is CHARACTER*1 — tells us which triangle of A is stored:
  • = 'U': Upper triangle of A is stored;
  • = 'L': Lower triangle of A is stored.

N

• N is INTEGER — the order of the matrix A. N >= 0.

A

• A is COMPLEX array, dimension (LDA,N) — the Hermitian matrix A, bestie.

On entry, the Hermitian 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 A = U**H*U or A = L*L**H.

LDA

• LDA is INTEGER — the leading dimension of the array A. LDA >= max(1,N).

INFO

• INFO is INTEGER — the exit-status tea ☕:
  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value
  • > 0: if INFO = i, the leading principal minor of order i is not positive, and the factorization could not be completed.

📜 Author 📜

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

📌 Definition at line 106 of file cpotrf.f.

📜 Author 📜

Generated automatically by Doxygen for LAPACK from the source code.

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Bottom-of-page sign-off, because bestie asked: the footer gives LAPACK, Version 3.12.0, and SRC/cpotrf.f(3) — that's the source/version/date corner, no extra date line, and that's the whole footer vibe. 🫶✨