SRC/ssytrs2.f(3)

okay so this is the SRC/ssytrs2.f(3) page from the Library Functions Manual, and we're about to read the whole thing together, bestie 🫶

✨ NAME ✨

SRC/ssytrs2.f

🦋 SYNOPSIS 🦋

Functions/Subroutines

       subroutine ssytrs2 (uplo, n, nrhs, a, lda, ipiv, b, ldb, work, info)

SSYTRS2 — that's the subroutine, and yes she's iconic 💅

💖 Function/Subroutine Documentation 💖

   subroutine ssytrs2 (character uplo, integer n, integer nrhs, real,
       dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, real,
       dimension( ldb, * ) b, integer ldb, real, dimension( * ) work, integer
       info)

SSYTRS2 — same name, no notes, periodt ✨

🌸 Purpose 🌸

SSYTRS2 solves a system of linear equations A*X = B with a real symmetric matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by SSYTRF and converted by SSYCONV. Literally the whole glow-up of this routine, bestie 💖

🎀 Parameters 🎀

• UPLO — UPLO is CHARACTER*1. Specifies whether the details of the factorization are stored as an upper or lower triangular matrix.
  • = 'U': Upper triangular, form is A = U*D*U**T;
  • = 'L': Lower triangular, form is A = L*D*L**T.
• N — N is INTEGER. The order of the matrix A. N >= 0.
• NRHS — NRHS is INTEGER. The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.
• A — A is REAL array, dimension (LDA,N). The block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by SSYTRF. Note that A is input / output. This might be counter-intuitive, and one may think that A is input only. A is input / output. This is because, at the start of the subroutine, we permute A in a form and then we permute A back to its original form at the end. Yes bestie, she goes both ways on input/output 😭💅
• LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N).
• IPIV — IPIV is INTEGER array, dimension (N). Details of the interchanges and the block structure of D as determined by SSYTRF.
• B — B is REAL array, dimension (LDB,NRHS). On entry, the right hand side matrix B. On exit, the solution matrix X.
• LDB — LDB is INTEGER. The leading dimension of the array B. LDB >= max(1,N).
• WORK — WORK is REAL array, dimension (N).
• INFO — INFO is INTEGER.
  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value

👑 Author 👑

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

Definition at line 130 of file ssytrs2.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

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okay that's the whole page, bestie — the footer is giving LAPACK, Version 3.12.0, source SRC/ssytrs2.f(3), and she absolutely ate 💅✨🫶