CGERFS(3)

🎀 CGERFS(3) 🎀

hiii bestie 💖 welcome to the Library Functions Manual page for CGERFS(3) — yes, the manual name is folded in right here instead of that big header line, we're doing it cute.

🌸 NAME 🌸

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

That's the file path this page points at, no cap. ✨

🦋 SYNOPSIS 🦋

Functions/Subroutines

subroutine CGERFS (trans, n, nrhs, a, lda, af, ldaf, ipiv, b, ldb, x,
    ldx, ferr, berr, work, rwork, info)
    CGERFS

💜 Function/Subroutine Documentation

subroutine CGERFS (character trans, integer n, integer nrhs, complex,
    dimension( lda, * ) a, integer lda, complex, dimension( ldaf, * ) af,
    integer ldaf, integer, dimension( * ) ipiv, complex, dimension( ldb, * )
    b, integer ldb, complex, dimension( ldx, * ) x, integer ldx, real,
    dimension( * ) ferr, real, dimension( * ) berr, complex, dimension( * )
    work, real, dimension( * ) rwork, integer info)
    CGERFS

🎯 Purpose 🎯

Okay so CGERFS has one main-character job: it improves the computed solution to a system of linear equations, and it provides error bounds and backward error estimates for that solution. That's the whole vibe. 💅

💅 Parameters 💅

• TRANS — TRANS is CHARACTER*1. It specifies the form of the system of equations:
  • = 'N': A * X = B (No transpose)
  • = 'T': A**T * X = B (Transpose)
  • = 'C': A**H * X = B (Conjugate transpose)
• N — N is INTEGER. The order of the matrix A. N >= 0. 🫶
• NRHS — NRHS is INTEGER. The number of right hand sides, i.e., the number of columns of the matrices B and X. NRHS >= 0. ✨
• A — A is COMPLEX array, dimension (LDA,N). The original N-by-N matrix A. 🌟
• LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N). 💖
• AF — AF is COMPLEX array, dimension (LDAF,N). The factors L and U from the factorization A = P*L*U as computed by CGETRF. 🔥
• LDAF — LDAF is INTEGER. The leading dimension of the array AF. LDAF >= max(1,N). 🌈
• IPIV — IPIV is INTEGER array, dimension (N). The pivot indices from CGETRF; for 1<=i<=N, row i of the matrix was interchanged with row IPIV(i). 👑
• B — B is COMPLEX array, dimension (LDB,NRHS). The right hand side matrix B. 🍓
• LDB — LDB is INTEGER. The leading dimension of the array B. LDB >= max(1,N). 💜
• X — X is COMPLEX array, dimension (LDX,NRHS). On entry, the solution matrix X, as computed by CGETRS. On exit, the improved solution matrix X. 🦋
• LDX — LDX is INTEGER. The leading dimension of the array X. LDX >= max(1,N). 🌸
• FERR — FERR is REAL array, dimension (NRHS). The estimated forward error bound for each solution vector X(j) (the j-th column of the solution matrix X). If XTRUE is the true solution corresponding to X(j), FERR(j) is an estimated upper bound for the magnitude of the largest element in (X(j) - XTRUE) divided by the magnitude of the largest element in X(j). The estimate is as reliable as the estimate for RCOND, and is almost always a slight overestimate of the true error. 😭💖
• BERR — BERR is REAL array, dimension (NRHS). The componentwise relative backward error of each solution vector X(j) (i.e., the smallest relative change in any element of A or B that makes X(j) an exact solution). 💀
• WORK — WORK is COMPLEX array, dimension (2*N). ✨
• RWORK — RWORK is REAL array, dimension (N). ⭐
• INFO — INFO is INTEGER.
  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value

🧚 Internal Parameters 🧚

• ITMAX — ITMAX is the maximum number of steps of iterative refinement. 🎀

🌟 Author 🌟

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

📍 Definition at line 184 of file cgerfs.f. 📍

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code. Not me, bestie — Doxygen did this one. 🙈

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okay that's the whole page 💖 — source/version tea: LAPACK Version 3.12.0, and the footer path is /home/abui...RC/cgerfs.f(3). Byeee 🫶