TESTING/LIN/cget02.f(3)

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πŸ’… TESTING/LIN/cget02.f(3) πŸ’…

okay so this is the TESTING/LIN/cget02.f page from the Library Functions Manual, and honestly? It’s giving β€œsmall but mighty Fortran testing routine” energy. Let’s get into it, bestie. 🫢


πŸ’– NAME πŸ’–

TESTING/LIN/cget02.f β€” yes, that’s the file, and it’s the main character of this page. Periodt. πŸ’…


🌸 SYNOPSIS 🌸

✨ Functions/Subroutines ✨

subroutine cget02 (trans, m, n, nrhs, a, lda, x, ldx, b, ldb, rwork,
    resid)
    CGET02

πŸ¦‹ Function/Subroutine Documentation πŸ¦‹

Here’s the full signature, copied exactly because we do not play fast and loose with Fortran, bestie:

subroutine cget02 (character trans, integer m, integer n, integer nrhs,
    complex, dimension( lda, * ) a, integer lda, complex, dimension( ldx, *
    ) x, integer ldx, complex, dimension( ldb, * ) b, integer ldb, real,
    dimension( * ) rwork, real resid)
    CGET02

πŸŽ€ Purpose πŸŽ€

CGET02 computes the residual for a solution of a system of linear equations op(A)*X = B:

RESID = norm(B - op(A)*X) / ( norm(op(A)) * norm(X) * EPS ),

where op(A) = A, A**T, or A**H, depending on TRANS, and EPS is the machine epsilon. Iconic little residual check, no cap. ✨

πŸ“ Parameters πŸ“

  • TRANS β€” TRANS is CHARACTER*1. 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)
  • M β€” M is INTEGER. The number of rows of the matrix A. M >= 0.
  • N β€” N is INTEGER. The number of columns of the matrix A. N >= 0.
  • NRHS β€” NRHS is INTEGER. The number of columns of B, the matrix of right hand sides. NRHS >= 0.
  • A β€” A is COMPLEX array, dimension (LDA,N). The original M x N matrix A.
  • LDA β€” LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,M).
  • X β€” X is COMPLEX array, dimension (LDX,NRHS). The computed solution vectors for the system of linear equations.
  • LDX β€” LDX is 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 β€” B is COMPLEX 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 - op(A)*X.
  • LDB β€” LDB is 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 β€” RWORK is REAL array, dimension (M).
  • RESID β€” RESID is REAL. The maximum over the number of right hand sides of norm(B - op(A)*X) / ( norm(op(A)) * norm(X) * EPS ).

πŸ‘‘ Author πŸ‘‘

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

Definition at line 132 of file cget02.f.


🌈 Author 🌈

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πŸ’– Cute sign-off: this is LAPACK Version 3.12.0, generated automatically by Doxygen for LAPACK from the source code. The footer doesn’t hand us a date, so I’m not inventing one, bestie β€” no cap. Periodt. πŸ’…
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