ZGET51(3)

💖 ZGET51(3) — Library Functions Manual 💖

okay so bestie, welcome to the ZGET51(3) page from the Library Functions Manual — we're in Unix manpage land, and this one is a LAPACK subroutine that checks a decomposition. The header vibes are folded in right here, no need to copy that whole first line, periodt. ✨

NAME 🎀

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/EIG/zget51.f

SYNOPSIS 🦋

Functions/Subroutines 🧚

       subroutine ZGET51 (itype, n, a, lda, b, ldb, u, ldu, v, ldv, work,
           rwork, result)
           ZGET51

Function/Subroutine Documentation 🫶

   subroutine ZGET51 (integer itype, integer n, complex*16, dimension( lda, * )
       a, integer lda, complex*16, dimension( ldb, * ) b, integer ldb,
       complex*16, dimension( ldu, * ) u, integer ldu, complex*16, dimension(
       ldv, * ) v, integer ldv, complex*16, dimension( * ) work, double
       precision, dimension( * ) rwork, double precision result)
       ZGET51

Purpose 🎯

okay so here's the whole point, bestie: ZGET51 generally checks a decomposition of the form

A = U B V**H

where **H means conjugate transpose and U and V are unitary. 💅

Specifically, if ITYPE=1:

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

If ITYPE=2, then:

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

If ITYPE=3, then:

RESULT = | I - U U**H | / ( n ulp )

Parameters 🌸

• ITYPE — ITYPE is INTEGER. Specifies the type of tests to be performed.
  • =1: RESULT = | A - U B V**H | / ( |A| n ulp )
  • =2: RESULT = | A - B | / ( |A| n ulp )
  • =3: RESULT = | I - U U**H | / ( n ulp )
• N — N is INTEGER. The size of the matrix. If it is zero, ZGET51 does nothing. It must be at least zero.
• A — A is COMPLEX*16 array, dimension (LDA, N). The original (unfactored) matrix.
• LDA — LDA is INTEGER. The leading dimension of A. It must be at least 1 and at least N.
• B — B is COMPLEX*16 array, dimension (LDB, N). 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 COMPLEX*16 array, dimension (LDU, N). The unitary 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 COMPLEX*16 array, dimension (LDV, N). The unitary matrix on the left-hand side in the decomposition. 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 COMPLEX*16 array, dimension (2*N**2).
• RWORK — RWORK is DOUBLE PRECISION array, dimension (N).
• RESULT — 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 153 of file zget51.f.

Author 📜

Generated automatically by Doxygen for LAPACK from the source code.

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okay that's the whole thing, bestie 💖 — this page is from LAPACK Version 3.12.0, source path /home/abui...IG/zget51.f(3), and that's the cute little sign-off. 🎀✨