CGET54(3)

okay so bestie 💖 welcome to the Library Functions Manual page for CGET54(3). Up top, the header path is /home/abui...IG/cget54.f(3) — and it literally appears twice in the header, because once was not enough 💅. This page is highkey about a LAPACK function, and it is giving “let’s validate a decomposition” energy.

✨ NAME ✨

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/EIG/cget54.f

🌸 SYNOPSIS 🌸

✨ Functions/Subroutines ✨

       subroutine CGET54 (n, a, lda, b, ldb, s, lds, t, ldt, u, ldu, v, ldv,
           work, result)
           CGET54

💅 Function/Subroutine Documentation 💅

okay here’s the full signature, no crumbs:

   subroutine CGET54 (integer n, complex, dimension( lda, * ) a, integer lda,
       complex, dimension( ldb, * ) b, integer ldb, complex, dimension( lds, *
       ) s, integer lds, complex, dimension( ldt, * ) t, integer ldt, complex,
       dimension( ldu, * ) u, integer ldu, complex, dimension( ldv, * ) v,
       integer ldv, complex, dimension( * ) work, real result)
       CGET54

🎯 Purpose

okay so CGET54 checks a generalized decomposition of the form

A = U*S*V'  and B = U*T* V'

where ' means conjugate transpose and U and V are unitary. That’s the whole vibe — no cap.

Specifically,

RESULT = ||( A - U*S*V', B - U*T*V' )|| / (||( A, B )||*n*ulp )

🔥 Parameters

Parameter check, one by one, nobody gets skipped:

• N — N is INTEGER. The size of the matrix. If it is zero, SGET54 does nothing (yes, the source says SGET54 there — I’m just relaying the message 🙈). It must be at least zero.
• A — A is COMPLEX array, dimension (LDA, N). The original (unfactored) matrix A.
• LDA — LDA is INTEGER. The leading dimension of A. It must be at least 1 and at least N.
• B — B is COMPLEX array, dimension (LDB, N). The original (unfactored) matrix B.
• LDB — LDB is INTEGER. The leading dimension of B. It must be at least 1 and at least N.
• S — S is COMPLEX array, dimension (LDS, N). The factored matrix S.
• LDS — LDS is INTEGER. The leading dimension of S. It must be at least 1 and at least N.
• T — T is COMPLEX array, dimension (LDT, N). The factored matrix T.
• LDT — LDT is INTEGER. The leading dimension of T. It must be at least 1 and at least N.
• U — U is COMPLEX array, dimension (LDU, N). The orthogonal matrix on the left-hand side in the decomposition.
• LDU — LDU is INTEGER. The leading dimension of U. LDU must be at least N and at least 1.
• V — V is COMPLEX array, dimension (LDV, N). The orthogonal matrix on the left-hand side in the decomposition.
• LDV — LDV is INTEGER. The leading dimension of V. LDV must be at least N and at least 1.
• WORK — WORK is COMPLEX array, dimension (3*N**2).
• RESULT — RESULT is REAL. The value RESULT, It is currently limited to 1/ulp, to avoid overflow. Errors are flagged by RESULT=10/ulp.

💖 Author 💖

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 154 of file cget54.f.

🤖 Author 🤖

Generated automatically by Doxygen for LAPACK from the source code.

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and that’s the whole page, bestie 🫶. The footer is giving LAPACK Version 3.12.0 and the path /home/abui...IG/cget54.f(3), with no extra date in sight — so that’s the source/version vibe we’re closing on 💜.