TESTING/LIN/ztrt01.f(3)

💅 NAME

okay bestie, this is the TESTING/LIN/ztrt01.f page from the Library Functions Manual, and it's serving ZTRT01 realness: a subroutine that checks the residual for a triangular matrix A times its inverse. ✨

🎀 SYNOPSIS

✨ Functions/Subroutines

• subroutine ztrt01 (uplo, diag, n, a, lda, ainv, ldainv, rcond, rwork, resid) — the whole ZTRT01 moment.

🦋 Function/Subroutine Documentation

subroutine ztrt01 (character uplo, character diag, integer n, complex*16,
    dimension( lda, * ) a, integer lda, complex*16, dimension( ldainv, * )
    ainv, integer ldainv, double precision rcond, double precision,
    dimension( * ) rwork, double precision resid)

ZTRT01

🌸 Purpose

okay so ZTRT01 computes the residual for a triangular matrix A times its inverse:

RESID = norm( A*AINV - I ) / ( N * norm(A) * norm(AINV) * EPS ),

where EPS is the machine epsilon. 🫶

🔥 Parameters

• UPLO — UPLO is CHARACTER*1. It says whether the matrix A is upper or lower triangular.
  • = 'U': Upper triangular
  • = 'L': Lower triangular
• DIAG — DIAG is CHARACTER*1. It says whether or not the matrix A is unit triangular.
  • = 'N': Non-unit triangular
  • = 'U': Unit triangular
• N — N is INTEGER. The order of the matrix A. N >= 0.
• A — A is COMPLEX*16 array, dimension (LDA,N). The triangular matrix A. If UPLO = 'U', the leading n by n upper triangular part of the array A contains the upper triangular matrix, and the strictly lower triangular part of A is not referenced. If UPLO = 'L', the leading n by n lower triangular part of the array A contains the lower triangular matrix, and the strictly upper triangular part of A is not referenced. If DIAG = 'U', the diagonal elements of A are also not referenced and are assumed to be 1.
• LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N).
• AINV — AINV is COMPLEX*16 array, dimension (LDAINV,N). On entry, the (triangular) inverse of the matrix A, in the same storage format as A. On exit, the contents of AINV are destroyed. 💀
• LDAINV — LDAINV is INTEGER. The leading dimension of the array AINV. LDAINV >= max(1,N).
• RCOND — RCOND is DOUBLE PRECISION. The reciprocal condition number of A, computed as 1/(norm(A) * norm(AINV)).
• RWORK — RWORK is DOUBLE PRECISION array, dimension (N).
• RESID — RESID is DOUBLE PRECISION. norm(A*AINV - I) / ( N * norm(A) * norm(AINV) * EPS ).

👑 Author

• Univ. of Tennessee
• Univ. of California Berkeley
• Univ. of Colorado Denver
• NAG Ltd.

Definition at line 123 of file ztrt01.f.

👑 Author

Generated automatically by Doxygen for LAPACK from the source code.

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💖 cute sign-off time: source/version footer tea is LAPACK, Version 3.12.0 — and the page doesn't print a separate date, so that's the whole sign-off vibe. mwah, bestie. 💅✨