SLAPTM(3)

💅 SLAPTM(3) — like, the tridiagonal girlie of LAPACK

okay so bestie, before we even start: this page lives at /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/slaptm.f — that's the whole NAME situation, it's a Fortran file path and honestly? iconic of it. This is the slaptm.f(3) manual page from LAPACK, and we're gonna walk through it together, no cap. 🎀

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✨ SYNOPSIS ✨

Functions/Subroutines

• subroutine SLAPTM (n, nrhs, alpha, d, e, x, ldx, beta, b, ldb) — like, this is her. This is the whole subroutine. SLAPTM. 💖

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🦋 Function/Subroutine Documentation 🦋

subroutine SLAPTM (integer n, integer nrhs, real alpha, real, dimension( * )
    d, real, dimension( * ) e, real, dimension( ldx, * ) x, integer ldx,
    real beta, real, dimension( ldb, * ) b, integer ldb)

SLAPTM. that's her name, that's her whole brand. ✨

🌸 Purpose 🌸

okay so here's the vibe:

!>
!> SLAPTM multiplies an N by NRHS matrix X by a symmetric tridiagonal
!> matrix A and stores the result in a matrix B.  The operation has the
!> form
!>
!>    B := alpha * A * X + beta * B
!>
!> where alpha may be either 1. or -1. and beta may be 0., 1., or -1.
!>

so she takes your N by NRHS matrix X, multiplies it by a symmetric tridiagonal matrix A, and drops the result into matrix B. the operation goes B := alpha * A * X + beta * B, and bestie, listen — alpha may only be 1. or -1., and beta may only be 0., 1., or -1. That's the whole assignment, periodt. 👑

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💜 Parameters

• N — N is INTEGER. it's the order of the matrix A, and the rule is N >= 0. fr fr, no negativity allowed here. 🙈
• NRHS — NRHS is INTEGER. the number of right hand sides, aka the number of columns of the matrices X and B. she's got options, she's multitalented. 💅
• ALPHA — ALPHA is REAL. the scalar alpha. girlypop must be 1. or -1. — otherwise, it is assumed to be 0. so like, behave or get zeroed out. 😭
• D — D is REAL array, dimension (N). the n diagonal elements of the tridiagonal matrix A. the main character diagonal, honestly. ⭐
• E — E is REAL array, dimension (N-1). the (n-1) subdiagonal or superdiagonal elements of A. the supporting cast, but make no mistake, she's essential. 🫶
• X — X is REAL array, dimension (LDX,NRHS). the N by NRHS matrix X. the input that gets multiplied, slay. 🔥
• LDX — LDX is INTEGER. the leading dimension of the array X. constraint: LDX >= max(N,1). respect the bounds or perish (metaphorically). 💀
• BETA — BETA is REAL. the scalar beta. must be 0., 1., or -1. — otherwise, it is assumed to be 1. so if you get cute with it, she just assumes 1. 😌
• B — B is REAL array, dimension (LDB,NRHS). on entry, the N by NRHS matrix B. on exit, B is overwritten by the matrix expression B := alpha * A * X + beta * B. so like, don't get attached to the old B, she's gone, she's been replaced, character development. ✨
• LDB — LDB is INTEGER. the leading dimension of the array B. constraint: LDB >= max(N,1). same energy as LDX, no exceptions. 🎀

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👑 Author

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

the whole squad, the whole collective, we stan a collaborative effort. 🌈

Definition at line 115 of file slaptm.f. — yeah, if you need to find her in the wild, that's exactly where she's at. 💖

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🌟 Author (yes, again, bestie)

Generated automatically by Doxygen for LAPACK from the source code. so like, a robot wrote this page, but she understood the assignment. 🧚

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and that's the whole page! 🦋 no cap, every parameter, every constraint, every !> comment retained, because we don't gatekeep details around here. LAPACK, Version 3.12.0, and this page is headed to you from /home/abui...IN/slaptm.f(3) — mwah, bye bestie! 💅✨🌸💜