SSYTRI(3)

📦 version 3.12.0, in opensuse-leap 16.0

💅 SSYTRI — LAPACK Library Functions Manual 💅

🌸 NAME 🌸

okay so this page is about this exact file path, bestie:

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

It's giving "we are documenting the Fortran source file" energy, and honestly? iconic. 🫶

✨ SYNOPSIS ✨

Functions/Subroutines

subroutine SSYTRI (uplo, n, a, lda, ipiv, work, info)
    SSYTRI

That's the quick vibe check: one subroutine, seven arguments, zero cap. 💅

🦋 Function/Subroutine Documentation 🦋

Here's the full signature, exactly as it is, no edits, no "I fixed it for you" behavior:

subroutine SSYTRI (character uplo, integer n, real, dimension( lda, * ) a,
    integer lda, integer, dimension( * ) ipiv, real, dimension( * ) work,
    integer info)

And the name again, because main character energy:

SSYTRI

Purpose 🎀

okay so SSYTRI computes the inverse of a real symmetric indefinite matrix A using the factorization A = U*D*U**T or A = L*D*L**T that was computed by SSYTRF. That's literally the whole purpose, and it ate. 🔥

Parameters 🫶

Every parameter matters here, bestie. Do not skip. 💖

UPLO

UPLO is CHARACTER*1. It 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. It's the order of the matrix A. N >= 0.

A

A is a REAL array, dimension (LDA,N).

On entry, it's the block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by SSYTRF.

On exit, if INFO = 0, it's the (symmetric) inverse of the original matrix. If UPLO = 'U', the upper triangular part of the inverse is formed and the part of A below the diagonal is not referenced; if UPLO = 'L', the lower triangular part of the inverse is formed and the part of A above the diagonal is not referenced. Read that twice, it's important. 💅

LDA

LDA is INTEGER. It's the leading dimension of the array A. LDA >= max(1,N).

IPIV

IPIV is an INTEGER array, dimension (N). It holds details of the interchanges and the block structure of D as determined by SSYTRF.

WORK

WORK is a REAL array, dimension (N).

INFO

INFO is INTEGER.

  • = 0: successful exit. 🎉
  • < 0: if INFO = -i, the i-th argument had an illegal value. 🙈
  • > 0: if INFO = i, D(i,i) = 0; the matrix is singular and its inverse could not be computed. 💀 no inverse for you.

Author 🫶

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

Definition at line 113 of file ssytri.f. 🎀

It's defined at line 113 of file ssytri.f. That's the coordinates, bestie. 📍

Author 🌈 (auto-generated)

Generated automatically by Doxygen for LAPACK from the source code.

💖 kisses, LAPACK Version 3.12.0 (ssytri.f(3)) — auto-generated by Doxygen, no cap. 💖

📦 where this page comes from