/home/abui...t01_rook.f(3)

💖 NAME 💖

okay so bestie, this is the Library Functions Manual page for /home/abui...t01_rook.f(3), and the NAME line is literally the full path below (yes, the whole source path, no cap):

/home/abuild/rpmbuild/BUILD/lapack-
static-3.12.0-build/lapack-3.12.0/TESTING/LIN/dsyt01_rook.f

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✨ SYNOPSIS ✨

Functions/Subroutines

subroutine DSYT01_ROOK (uplo, n, a, lda, afac, ldafac, ipiv, c, ldc,
           rwork, resid)

and then it literally says DSYT01_ROOK again underneath, because iconic behavior 💅

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🦋 Function/Subroutine Documentation 🦋

DSYT01_ROOK is the main character here, and here's the full signature, copied exactly because we do not play with code:

subroutine DSYT01_ROOK (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)

then, yes, DSYT01_ROOK appears again under the signature. slay ✨

🎀 Purpose 🎀

okay so here's the tea: DSYT01_ROOK 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. it's giving factorization vibe check 🔥

🍓 Parameters 🍓

• 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. pick your triangle, bestie 💚
• N — is INTEGER. The number of rows and columns of the matrix A. N >= 0.
• A — is DOUBLE PRECISION array, dimension (LDA,N). The original symmetric matrix A.
• LDA — is INTEGER. The leading dimension of the array A. LDA >= max(1,N)
• 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_ROOK.
• LDAFAC — is INTEGER. The leading dimension of the array AFAC. LDAFAC >= max(1,N).
• IPIV — is INTEGER array, dimension (N). The pivot indices from DSYTRF_ROOK.
• C — is DOUBLE PRECISION array, dimension (LDC,N).
• LDC — is INTEGER. The leading dimension of the array C. LDC >= max(1,N).
• RWORK — is DOUBLE PRECISION array, dimension (N).
• 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 ). residual said what it said 🍑

👑 Author 👑

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

Definition at line 122 of file dsyt01_rook.f.

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🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

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cute sign-off bestie: this footer is source/version LAPACK Version 3.12.0 and title /home/abui...t01_rook.f(3) — there’s no separate date printed on that footer line, so I’m not inventing one 💅🫶🌸