TESTING/LIN/dget08.f(3)

🌸 TESTING/LIN/dget08.f(3) 🌸

Hey bestie 💖 you're looking at the Library Functions Manual page for TESTING/LIN/dget08.f(3) — yes, the LAPACK testing/LIN corner of the universe. This one is all about DGET08, a subroutine that does residual math for linear systems, and we are gonna cover every single argument because that's the vibe. ✨

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🎀 NAME 🎀

TESTING/LIN/dget08.f

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

subroutine dget08 (trans, m, n, nrhs, a, lda, x, ldx, b, ldb, rwork, resid)

DGET08

💖 Function/Subroutine Documentation 💖

subroutine dget08 (character trans, integer m, integer n, integer nrhs,
     double precision, dimension( lda, * ) a, integer lda, double precision,
     dimension( ldx, * ) x, integer ldx, double precision, dimension( ldb, *
     ) b, integer ldb, double precision, dimension( * ) rwork, double
     precision resid)

DGET08

🎯 Purpose

DGET08 computes the residual for a solution of a system of linear equations

A*x = b  or  A'*x = b:
   RESID = norm(B - A*X,inf) / ( norm(A,inf) * norm(X,inf) * EPS ),

where EPS is the machine epsilon. Periodt. 💅

📋 Parameters

Okay bestie, here's every parameter — no skipping, no summarizing, we're doing the whole list. 🫶

• TRANS — CHARACTER*1. Specifies the form of the system of equations:
  • = 'N': A *x = b
  • = 'T': A'*x = b, where A' is the transpose of A
  • = 'C': A'*x = b, where A' is the transpose of A
• M — INTEGER. The number of rows of the matrix A. M >= 0. 🍓
• N — INTEGER. The number of columns of the matrix A. N >= 0. 🍓
• NRHS — INTEGER. The number of columns of B, the matrix of right hand sides. NRHS >= 0. 💜
• A — DOUBLE PRECISION array, dimension (LDA,N). The original M x N matrix A.
• LDA — INTEGER. The leading dimension of the array A. LDA >= max(1,M). ✨
• X — DOUBLE PRECISION array, dimension (LDX,NRHS). The computed solution vectors for the system of linear equations.
• LDX — INTEGER. The leading dimension of the array X. If TRANS = 'N', LDX >= max(1,N); if TRANS = 'T' or 'C', LDX >= max(1,M). 🔥
• B — DOUBLE PRECISION array, dimension (LDB,NRHS). On entry, the right hand side vectors for the system of linear equations. On exit, B is overwritten with the difference B - A*X. 👀
• LDB — INTEGER. The leading dimension of the array B. IF TRANS = 'N', LDB >= max(1,M); if TRANS = 'T' or 'C', LDB >= max(1,N). 💀
• RWORK — DOUBLE PRECISION array, dimension (M). 🌈
• RESID — DOUBLE PRECISION. The maximum over the number of right hand sides of norm(B - A*X) / ( norm(A) * norm(X) * EPS ). 👑

🧚 Author 🧚

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

Definition at line 131 of file dget08.f.

🧚 Author 🧚

Generated automatically by Doxygen for LAPACK from the source code.

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Okay that's the whole page, bestie! 🫶 This is from LAPACK, Version 3.12.0, and it's the TESTING/LIN/dget08.f(3) page. The footer doesn't list a date, so no fake date energy here — auto-generated by Doxygen for LAPACK from the source code, periodt. 💅✨