DGET54(3)

💅 NAME

Okay bestie 💖 this is dget54(3) from the Library Functions Manual — manual name folded in, header line not copy-pasted, periodt. The file living its best life behind this page is:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/EIG/dget54.f

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✨ SYNOPSIS

🧚 Functions/Subroutines

subroutine DGET54 (n, a, lda, b, ldb, s, lds, t, ldt, u, ldu, v, ldv,
    work, result)
    DGET54

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🦋 Function/Subroutine Documentation

subroutine DGET54 (integer n, double precision, dimension( lda, * ) a,
    integer lda, double precision, dimension( ldb, * ) b, integer ldb,
    double precision, dimension( lds, * ) s, integer lds, double precision,
    dimension( ldt, * ) t, integer ldt, double precision, dimension( ldu, *
    ) u, integer ldu, double precision, dimension( ldv, * ) v, integer ldv,
    double precision, dimension( * ) work, double precision result)
    DGET54

Yep, it’s DGET54 again — main character energy 👑.

🎀 Purpose

DGET54 checks a generalized decomposition of the form

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

where ' means transpose and U and V are orthogonal.

Specifically,

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

🌸 Parameters

• N — N is INTEGER. The size of the matrix. If it is zero, DGET54 does nothing. It must be at least zero.
• A — A is DOUBLE PRECISION 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 DOUBLE PRECISION 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 DOUBLE PRECISION 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 DOUBLE PRECISION 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 DOUBLE PRECISION 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 DOUBLE PRECISION 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 DOUBLE PRECISION array, dimension (3*N**2).
• RESULT — RESULT is DOUBLE PRECISION. 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 dget54.f.

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💖 Author

Generated automatically by Doxygen for LAPACK from the source code.

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Source/version sign-off 🫶: LAPACK Version 3.12.0, footer path /home/abui...IG/dget54.f(3). No explicit date shows up in that footer, so I’m not inventing one ✨.