DGET51(3)

okay bestie, this is DGET51(3) from the LAPACK Library Functions Manual, and we are about to give this decomposition test the full main-character treatment 💅 no facts left behind, no cap.

🎀 NAME 🎀

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/EIG/dget51.f

That’s literally the NAME section, bestie — a whole file path and everything. 🫶

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

subroutine DGET51 (itype, n, a, lda, b, ldb, u, ldu, v, ldv, work,
    result)
    DGET51

🦋 Function/Subroutine Documentation 🦋

subroutine DGET51 (integer itype, integer n, double precision, dimension(
    lda, * ) a, integer lda, double precision, dimension( ldb, * ) b,
    integer ldb, double precision, dimension( ldu, * ) u, integer ldu,
    double precision, dimension( ldv, * ) v, integer ldv, double precision,
    dimension( * ) work, double precision result)

DGET51

🎯 Purpose 🎯

DGET51 generally checks a decomposition of the form

A = U B V'

where ' means transpose and U and V are orthogonal.

Specifically, if ITYPE=1

RESULT = | A - U B V' | / ( |A| n ulp )

If ITYPE=2, then:

RESULT = | A - B | / ( |A| n ulp )

If ITYPE=3, then:

RESULT = | I - UU' | / ( n ulp )

🧸 Parameters 🧸

• ITYPE is INTEGER — specifies the type of tests to be performed.
  • =1: RESULT = | A - U B V' | / ( |A| n ulp )
  • =2: RESULT = | A - B | / ( |A| n ulp )
  • =3: RESULT = | I - UU' | / ( n ulp )
• N is INTEGER — the size of the matrix. If it is zero, DGET51 does nothing. It must be at least zero.
• A is DOUBLE PRECISION array, dimension (LDA, N) — the original (unfactored) matrix.
• LDA is INTEGER — the leading dimension of A. It must be at least 1 and at least N.
• B is DOUBLE PRECISION array, dimension (LDB, N) — the factored matrix.
• LDB is INTEGER — the leading dimension of B. It must be at least 1 and at least N.
• U is DOUBLE PRECISION array, dimension (LDU, N) — the orthogonal matrix on the left-hand side in the decomposition. Not referenced if ITYPE=2.
• LDU is INTEGER — the leading dimension of U. LDU must be at least N and at least 1.
• V is DOUBLE PRECISION array, dimension (LDV, N) — the orthogonal matrix on the left-hand side in the decomposition. Not referenced if ITYPE=2.
• LDV is INTEGER — the leading dimension of V. LDV must be at least N and at least 1.
• WORK is DOUBLE PRECISION array, dimension (2*N**2).
• RESULT is DOUBLE PRECISION — the values computed by the test specified by ITYPE. The value 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 147 of file dget51.f.

🪄 Author 🪄

Generated automatically by Doxygen for LAPACK from the source code.

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mwah 💋 and that’s the whole page, bestie — signed off with the footer’s LAPACK, Version 3.12.0, and /home/abui...IG/dget51.f(3). Periodt. 🫶✨