SRC/cpptrs.f(3)

💖 NAME 💖

SRC/cpptrs.f — no cap, that's the whole name, bestie, she's lowkey mysterious like that ✨

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🦋 SYNOPSIS 🦋

Functions/Subroutines

• subroutine cpptrs (uplo, n, nrhs, ap, b, ldb, info) — CPPTRS 👑

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🎀 Function/Subroutine Documentation 🎀

subroutine cpptrs (character uplo, integer n, integer nrhs, complex,
    dimension( * ) ap, complex, dimension( ldb, * ) b, integer ldb, integer
    info)

CPPTRS 💅

✨ Purpose ✨

!> CPPTRS solves a system of linear equations A*X = B with a Hermitian !> positive definite matrix A in packed storage using the Cholesky !> factorization A = UH*U or A = L*LH computed by CPPTRF. !>

Like, okay — she's out here solving A*X = B for you, where A is Hermitian positive definite and lives in packed storage (so she's compact and efficient, we stan 🫶). She uses the Cholesky factorization A = U**H*U or A = L*L**H that CPPTRF already cooked up. Iconic teamwork fr fr 🔥

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🌸 Parameters 🌸

UPLO

!> UPLO is CHARACTER*1 !> = 'U': Upper triangle of A is stored; !> = 'L': Lower triangle of A is stored. !>

Bestie, this one's just vibes selection: 'U' means the upper triangle of A is the one being stored, 'L' means the lower triangle. Choose your fighter 🎀

N

!> N is INTEGER !> The order of the matrix A. N >= 0. !>

The order of matrix A, i.e. N >= 0. Keep it non-negative or she will simply not ✋

NRHS

!> NRHS is INTEGER !> The number of right hand sides, i.e., the number of columns !> of the matrix B. NRHS >= 0. !>

How many right hand sides you've got, so basically the number of columns of matrix B. NRHS >= 0, periodt 💅

AP

!> AP is COMPLEX array, dimension (N*(N+1)/2) !> The triangular factor U or L from the Cholesky factorization !> A = UH*U or A = L*LH, packed columnwise in a linear !> array. The j-th column of U or L is stored in the array AP !> as follows: !> if UPLO = 'U', AP(i + (j-1)j/2) = U(i,j) for 1<=i<=j; !> if UPLO = 'L', AP(i + (j-1)(2n-j)/2) = L(i,j) for j<=i<=n. !>

AP is a COMPLEX array of dimension (N*(N+1)/2) — she's the triangular factor U or L from that Cholesky factorization A = U**H*U or A = L*L**H, packed columnwise into one linear array. The j-th column of U or L sits in AP like this:

• if UPLO = 'U', AP(i + (j-1)*j/2) = U(i,j) for 1<=i<=j;
• if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n.

Index math but make it fashion 🧚 Write it down, iykyk 💀

B

!> B is COMPLEX array, dimension (LDB,NRHS) !> On entry, the right hand side matrix B. !> On exit, the solution matrix X. !>

B is a COMPLEX array of dimension (LDB,NRHS). On entry she's the right hand side matrix B; on exit she's transformed — the solution matrix X. Glow-up arc, main character energy 👑

LDB

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

LDB is an INTEGER: the leading dimension of array B. Must be LDB >= max(1,N). Respect the constraint or it's giving error 😭

INFO

!> INFO is INTEGER !> = 0: successful exit !> < 0: if INFO = -i, the i-th argument had an illegal value !>

• INFO = 0 — successful exit, we love a clean win ✨
• INFO < 0 — if INFO = -i, the i-th argument had an illegal value 🙈

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🌈 Author 🌈

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

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⭐ Definition at line 107 of file cpptrs.f. ⭐

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💜 Author 💜

Generated automatically by Doxygen for LAPACK from the source code. She's not hand-written, she's generated, and honestly? Still ate 💅

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LAPACK — Version 3.12.0 🦋 that's the whole squad signing off, SRC/cpptrs.f(3), mwah 💖🎀🌸