spotrf.f(3)

💖 NAME 💖

This is the LAPACK manual page for spotrf.f — that's the name, bestie, and it's giving “Cholesky factorization but make it a LAPACK variant” energy. 💅✨

🦋 SYNOPSIS 🦋

✨ Functions/Subroutines ✨

• subroutine spotrf (UPLO, N, A, LDA, INFO) — SPOTRF VARIANT: top-looking block version of the algorithm, calling Level 3 BLAS.

🌈 FUNCTION/SUBROUTINE DOCUMENTATION 🌈

🎀 subroutine spotrf 🎀

subroutine spotrf (character UPLO, integer N, real, dimension( lda, * ) A,
    integer LDA, integer INFO)

Okay so the variant note is literally: SPOTRF VARIANT: top-looking block version of the algorithm, calling Level 3 BLAS. 👑

💜 Purpose

SPOTRF computes the Cholesky factorization of a real symmetric positive definite matrix A.

The factorization has the form

A = U**T * U,  if UPLO = 'U', or
A = L  * L**T,  if UPLO = 'L',

where U is an upper triangular matrix and L is lower triangular.

This is the top-looking block version of the algorithm, calling Level 3 BLAS. ✨

🧚 Parameters

• UPLO — UPLO is CHARACTER*1
  • = '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 REAL 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 A = U**T*U or A = L*L**T.

• LDA — LDA is INTEGER; the leading dimension of the array A. LDA >= max(1,N).
• INFO — INFO is INTEGER
  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value
  • > 0: if INFO = i, the leading minor of order i is not positive definite, and the factorization could not be completed.

👑 Author

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

📅 Date

December 2016

Definition at line 102 of file VARIANTS/cholesky/TOP/spotrf.f.

💫 AUTHOR 💫

Generated automatically by Doxygen for LAPACK from the source code.

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Okay bestie, that's the whole page 🫶 This one is LAPACK Version 3.8.0, dated Tue Nov 14 2017, and the page itself is spotrf.f(3). Slay. 💖🎀🦋