SGET51(3)

💅 NAME 💅

okay bestie, this is the Library Functions Manual page for /home/abui...IG/sget51.f(3) — folding that header in like a good lil note instead of copy-pasting the whole line 💅

The actual NAME is:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/EIG/sget51.f

✨ SYNOPSIS ✨

📚 Functions/Subroutines 📚

subroutine SGET51 (itype, n, a, lda, b, ldb, u, ldu, v, ldv, work,
    result)

and the subroutine name is SGET51 🫶

🦋 Function/Subroutine Documentation 🦋

👑 SGET51 👑

subroutine SGET51 (integer itype, integer n, real, dimension( lda, * ) a,
    integer lda, real, dimension( ldb, * ) b, integer ldb, real, dimension(
    ldu, * ) u, integer ldu, real, dimension( ldv, * ) v, integer ldv, real,
    dimension( * ) work, real result)

SGET51 — that's the whole glow-up name, periodt ✨

🎯 Purpose 🎯

okay so SGET51 generally checks a decomposition of the form

A = U B V'

where ' means transpose and U and V are orthogonal. iconic.

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

ITYPE is INTEGER and 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

N is INTEGER — it's the size of the matrix. If it is zero, SGET51 does nothing. It must be at least zero.

A

A is a REAL array, dimension (LDA, N). It's the original (unfactored) matrix, the main character before the glow-up.

LDA

LDA is INTEGER — the leading dimension of A. It must be at least 1 and at least N.

B

B is a REAL array, dimension (LDB, N). It's the factored matrix.

LDB

LDB is INTEGER — the leading dimension of B. It must be at least 1 and at least N.

U

U is a REAL array, dimension (LDU, N). It's the orthogonal matrix on the left-hand side in the decomposition. Not referenced if ITYPE=2.

LDU

LDU is INTEGER — the leading dimension of U. LDU must be at least N and at least 1.

V

V is a REAL array, dimension (LDV, N). The doc says it's the orthogonal matrix on the left-hand side in the decomposition too (same wording as U, no cap — keeping it exactly as written). Not referenced if ITYPE=2.

LDV

LDV is INTEGER — the leading dimension of V. LDV must be at least N and at least 1.

WORK

WORK is a REAL array, dimension (2*N**2).

RESULT

RESULT is REAL — 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 sget51.f.

🧚 Author 🧚

Generated automatically by Doxygen for LAPACK from the source code.

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that's the whole page, bestie 🫶 — brought to you by LAPACK Version 3.12.0, and the footer file path /home/abui...IG/sget51.f(3) ✨💖 the footer doesn't show a date, just the version-and-path vibe, iykyk 🎀