TESTING/LIN/csyt02.f(3)

💖 NAME 💖

TESTING/LIN/csyt02.f — yes bestie, that’s the page. It’s the manual home for the csyt02 subroutine in the TESTING/LIN corner of LAPACK. Iconic file path, no cap. 💅

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✨ SYNOPSIS ✨

🎀 Functions/Subroutines 🎀

Okay so the callable vibe is literally this:

       subroutine csyt02 (uplo, n, nrhs, a, lda, x, ldx, b, ldb, rwork, resid)
           CSYT02

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🦋 Function/Subroutine Documentation 🦋

Here’s the full signature, character-for-character, because we do not play with exact code:

   subroutine csyt02 (character uplo, 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)
       CSYT02

CSYT02

🌸 Purpose 🌸

Okay so CSYT02 computes the residual for a solution to a complex symmetric system of linear equations A*x = b:

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

where EPS is the machine epsilon. That’s the whole purpose, and it ate. 💅

🎀 Parameters 🎀

• UPLO — CHARACTER*1. Specifies whether the upper or lower triangular part of the symmetric matrix A is stored:
  • = 'U': Upper triangular
  • = 'L': Lower triangular
• N — INTEGER. The number of rows and columns of the matrix A. N >= 0.
• NRHS — INTEGER. The number of columns of B, the matrix of right hand sides. NRHS >= 0.
• A — COMPLEX array, dimension (LDA,N). The original complex symmetric matrix A.
• LDA — INTEGER. The leading dimension of the array A. LDA >= max(1,N).
• X — COMPLEX array, dimension (LDX,NRHS). The computed solution vectors for the system of linear equations.
• LDX — INTEGER. The leading dimension of the array X. LDX >= max(1,N).
• B — 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 - A*X.

Bestie, watch out: B gets overwritten on exit with B - A*X. That’s not a drill, that’s literally the spec. 🫶

• LDB — INTEGER. The leading dimension of the array B. LDB >= max(1,N).
• RWORK — REAL array, dimension (N).
• RESID — REAL. 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 125 of file csyt02.f.

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🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

Not me being auto-generated and still serving main character energy. ✨

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That’s the whole page, bestie. Footer tea: LAPACK, Version 3.12.0, TESTING/LIN/csyt02.f(3) — no date listed in this footer, so we’re not inventing one, periodt. 💖🎀🦋