DPOTF2(3)

DPOTF2 💅 — Library Functions Manual

Okay bestie, welcome to the dpotf2.f(3) glow-up page. The header path is /home/abui...RC/dpotf2.f(3), and it lives in the Library Functions Manual. This is the whole tea on DPOTF2: Cholesky factorization, unblocked algorithm, Level 2 BLAS, no cap. Slay. ✨

💖 NAME 💖

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/dpotf2.f

That's the source file, periodt. It's giving "very specific build path" energy, and we respect it. 🎀

✨ SYNOPSIS ✨

Functions/Subroutines

       subroutine DPOTF2 (uplo, n, a, lda, info)

DPOTF2 computes the Cholesky factorization of a symmetric/Hermitian positive definite matrix (unblocked algorithm). Literally iconic linear algebra behavior. 🔥

🦋 Function/Subroutine Documentation 🦋

   subroutine DPOTF2 (character uplo, integer n, double precision, dimension(
       lda, * ) a, integer lda, integer info)

DPOTF2 computes the Cholesky factorization of a symmetric/Hermitian positive definite matrix (unblocked algorithm). Yes, same energy as the synopsis — it's a repeating motif, and it ate. 💅

🎀 Purpose 🎀

So the Purpose section says: DPOTF2 computes the Cholesky factorization of a real symmetric positive definite matrix A. Not "symmetric/Hermitian" here — specifically real symmetric, bestie. Keep that distinction in your notes. 🫶

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. It also says this is the unblocked version of the algorithm, calling Level 2 BLAS. 🌸

🌈 Parameters 🌈

• UPLO — UPLO is CHARACTER*1. It 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. It's the order of the matrix A. Constraint: N >= 0.
• A — A is DOUBLE PRECISION array, dimension (LDA,N). On entry, it's 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. No extra seasoning, that's the exact deal. 💜

• LDA — LDA is INTEGER. It's the leading dimension of the array A. Constraint: LDA >= max(1,N).
• INFO — INFO is INTEGER.
  • = 0 — successful exit
  • < 0 — if INFO = -k, the k-th argument had an illegal value
  • > 0 — if INFO = k, the leading principal minor of order k 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 108 of file dpotf2.f.

🌸 Author 🌸

Generated automatically by Doxygen for LAPACK from the source code.

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Sign-off tea: this page is from LAPACK Version 3.12.0, and the footer path is /home/abui...RC/dpotf2.f(3). Periodt. 💖