TESTING/LIN/dsyt01.f(3)

💅 NAME

okay bestie, this page is for TESTING/LIN/dsyt01.f(3) — and the manual page name is literally TESTING/LIN/dsyt01.f. lowkey iconic already.

✨ SYNOPSIS

Under Functions/Subroutines you get this:

subroutine dsyt01 (uplo, n, a, lda, afac, ldafac, ipiv, c, ldc, rwork, resid)

and then the name DSYT01 shows up like the main character it is. 👑

🫶 Function/Subroutine Documentation

subroutine dsyt01

subroutine dsyt01 (character uplo, integer n, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( ldafac, * ) afac, integer ldafac, integer, dimension( * ) ipiv, double precision, dimension( ldc, * ) c, integer ldc, double precision, dimension( * ) rwork, double precision resid)

DSYT01

🎀 Purpose:

Bestie, DSYT01 reconstructs a symmetric indefinite matrix A from its block L*D*L' or U*D*U' factorization and computes the residual

norm( C - A ) / ( N * norm(A) * EPS ),

where C is the reconstructed matrix and EPS is the machine epsilon. no cap, that’s the whole purpose. ✨

💖 Parameters

• UPLO — UPLO is CHARACTER*1; specifies whether the upper or lower triangular part of the symmetric matrix A is stored: = 'U': Upper triangular, = 'L': Lower triangular.
• N — N is INTEGER; the number of rows and columns of the matrix A. N >= 0.
• A — A is DOUBLE PRECISION array, dimension (LDA,N); the original symmetric matrix A.
• LDA — LDA is INTEGER; the leading dimension of the array A. LDA >= max(1,N)
• AFAC — AFAC is DOUBLE PRECISION array, dimension (LDAFAC,N); the factored form of the matrix A. AFAC contains the block diagonal matrix D and the multipliers used to obtain the factor L or U from the block L*D*L' or U*D*U' factorization as computed by DSYTRF.
• LDAFAC — LDAFAC is INTEGER; the leading dimension of the array AFAC. LDAFAC >= max(1,N).
• IPIV — IPIV is INTEGER array, dimension (N); the pivot indices from DSYTRF.
• C — C is DOUBLE PRECISION array, dimension (LDC,N).
• LDC — LDC is INTEGER; the leading dimension of the array C. LDC >= max(1,N).
• RWORK — RWORK is DOUBLE PRECISION array, dimension (N).
• RESID — RESID is DOUBLE PRECISION; If UPLO = 'L', norm(L*D*L' - A) / ( N * norm(A) * EPS ); If UPLO = 'U', norm(U*D*U' - A) / ( N * norm(A) * EPS ).

👑 Author

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

Definition at line 122 of file dsyt01.f.

🌈 Author

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xoxo, your LAPACK bestie 💖 — LAPACK Version 3.12.0, page TESTING/LIN/dsyt01.f(3). mwah! 🎀