SRC/ssyswapr.f(3)

💅 SRC/ssyswapr.f

okay bestie, so this page is from the LAPACK Library Functions Manual, and it's literally all about one lil subroutine that swaps rows and columns around in a symmetric matrix. iykyk 🦋

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✨ SYNOPSIS ✨

Functions/Subroutines

• subroutine ssyswapr (uplo, n, a, lda, i1, i2) — SSYSWAPR applies an elementary permutation on the rows and columns of a symmetric matrix. slay 💅

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🎀 Function/Subroutine Documentation 🎀

subroutine ssyswapr (character uplo, integer n, real, dimension( lda, * ) a, integer lda, integer i1, integer i2)

SSYSWAPR applies an elementary permutation on the rows and columns of a symmetric matrix. no cap, that's the whole gig 💖

Purpose:

!>
!> SSYSWAPR applies an elementary permutation on the rows and the columns of
!> a symmetric matrix.
!>

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.
!>

so UPLO is a CHARACTER*1 and it tells you whether the factorization details are chilling in an upper or a 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.
!>

N is INTEGER, the order of the matrix A, and it's gotta be N >= 0. respectful. 👑

A

!>          A is REAL array, dimension (LDA,*)
!>          On entry, the N-by-N matrix A. On exit, the permuted matrix
!>          where the rows I1 and I2 and columns I1 and I2 are interchanged.
!>          If UPLO = 'U', the interchanges are applied to the upper
!>          triangular part and the strictly lower triangular part of A is
!>          not referenced; if UPLO = 'L', the interchanges are applied to
!>          the lower triangular part and the part of A above the diagonal
!>          is not referenced.
!>

A is a REAL array, dimension (LDA,*) — main character energy fr fr 🌟

• on entry: the N-by-N matrix A
• on exit: the permuted matrix, where the rows I1 and I2 and columns I1 and I2 are interchanged
• if UPLO = 'U': the interchanges are applied to the upper triangular part, and the strictly lower triangular part of A is not referenced
• if UPLO = 'L': the interchanges are applied to the lower triangular part, and the part of A above the diagonal is not referenced

lowkey important: whichever half you don't pick is not referenced — don't come for it, it's not invited to the party 🙈

LDA

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

LDA is INTEGER, the leading dimension of the array A, and it must be LDA >= max(1,N). periodt. 💯

I1

!>          I1 is INTEGER
!>          Index of the first row to swap
!>

I1 is INTEGER — index of the first row to swap 🍓

I2

!>          I2 is INTEGER
!>          Index of the second row to swap
!>

I2 is INTEGER — index of the second row to swap 🌸

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👑 Author 👑

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

Definition at line 99 of file ssyswapr.f. ✨

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🌈 Author (again, yeah)

Generated automatically by Doxygen for LAPACK from the source code. not me being auto-generated, iconic behaviour honestly 💀

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and that's the whole page bestie — LAPACK Version 3.12.0, SRC/ssyswapr.f(3), mwah 💖 🫶 🎀