DLA_SYRPVGRW(3)

💅 DLA_SYRPVGRW(3)

okay so this page lives in the Library Functions Manual and it's literally all about one little function that does one very specific slay of a job 💖

---

🌸 NAME

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

like yes that's the whole name, she's a file path girlie and we respect it 🫶

---

✨ SYNOPSIS

Functions/Subroutines

• double precision function DLA_SYRPVGRW (uplo, n, info, a, lda, af, ldaf, ipiv, work) — DLA_SYRPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a symmetric indefinite matrix.

---

🦋 Function/Subroutine Documentation

okay bestie here's the full signature, copy it exactly, no cap:

double precision function DLA_SYRPVGRW (character*1 uplo, integer n, integer
    info, double precision, dimension( lda, * ) a, integer lda, double
    precision, dimension( ldaf, * ) af, integer ldaf, integer, dimension( *
    ) ipiv, double precision, dimension( * ) work)

DLA_SYRPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a symmetric indefinite matrix. periodt. ✨

🎀 Purpose

!> !> !> DLA_SYRPVGRW computes the reciprocal pivot growth factor !> norm(A)/norm(U). The norm is used. If this is !> much less than 1, the stability of the LU factorization of the !> (equilibrated) matrix A could be poor. This also means that the !> solution X, estimated condition numbers, and error bounds could be !> unreliable. !>

lowkey important: if that value is much less than 1, the stability of the LU factorization of the (equilibrated) matrix A could be poor 😭 and that also means the solution X, the estimated condition numbers, and the error bounds could be unreliable. so like… do with that what you will 🙈

💜 Parameters

UPLO

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

• 'U' — upper triangle of A is stored
• 'L' — lower triangle of A is stored

pick your triangle, main character 💅

N

!> N is INTEGER !> The number of linear equations, i.e., the order of the !> matrix A. N >= 0. !>

the number of linear equations, i.e. the order of the matrix A. and N >= 0, we do not do negative here 🚫

INFO

!> INFO is INTEGER !> The value of INFO returned from DSYTRF, .i.e., the pivot in !> column INFO is exactly 0. !>

the value of INFO returned from DSYTRF, (that .i.e. is literally how it's written, iykyk) — the pivot in column INFO is exactly 0.

A

!> A is DOUBLE PRECISION array, dimension (LDA,N) !> On entry, the N-by-N matrix A. !>

DOUBLE PRECISION array, dimension (LDA,N). on entry, it's the N-by-N matrix A. she is the moment 👑

LDA

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

the leading dimension of the array A. LDA >= max(1,N). math checks, we love to see it 🌈

AF

!> AF is DOUBLE PRECISION array, dimension (LDAF,N) !> The block diagonal matrix D and the multipliers used to !> obtain the factor U or L as computed by DSYTRF. !>

DOUBLE PRECISION array, dimension (LDAF,N). it holds the block diagonal matrix D plus the multipliers used to obtain the factor U or L as computed by DSYTRF. very demure, very factored ✨

LDAF

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

the leading dimension of the array AF. LDAF >= max(1,N). same energy, different letter 🎀

IPIV

!> IPIV is INTEGER array, dimension (N) !> Details of the interchanges and the block structure of D !> as determined by DSYTRF. !>

INTEGER array, dimension (N). details of the interchanges and the block structure of D as determined by DSYTRF. the receipts, basically 🧾

WORK

!> WORK is DOUBLE PRECISION array, dimension (2*N) !>

DOUBLE PRECISION array, dimension (2*N). that's it, that's the whole description, she's mysterious 💀

---

👑 Author

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

the whole squad showed up fr fr 🫶

Definition at line 120 of file dla_syrpvgrw.f. ⭐

---

🌺 Author

Generated automatically by Doxygen for LAPACK from the source code. (not a human, just a robot doing its little robot thing 🤖✨)

---

and that's the page!! sign-off time: this is LAPACK, Version 3.12.0, from /home/abui..._syrpvgrw.f(3) — mwah, go forth and compute your reciprocal pivot growth factor responsibly 💖💅🔥