DSYT01_3(3)

🌸 NAME 🌸

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/dsyt01_3.f — okay bestie, this is the source-file main character for the DSYT01_3 routine. It’s giving LAPACK testing-code energy, and that’s the whole NAME section, periodt. 💅

✨ SYNOPSIS ✨

Functions/Subroutines

       subroutine DSYT01_3 (uplo, n, a, lda, afac, ldafac, e, ipiv, c, ldc,
           rwork, resid)
           DSYT01_3

💖 Function/Subroutine Documentation 💖

   subroutine DSYT01_3 (character uplo, integer n, double precision, dimension(
       lda, * ) a, integer lda, double precision, dimension( ldafac, * ) afac,
       integer ldafac, double precision, dimension( * ) e, integer, dimension(
       * ) ipiv, double precision, dimension( ldc, * ) c, integer ldc, double
       precision, dimension( * ) rwork, double precision resid)
       DSYT01_3

🎯 Purpose 🎯

Okay so DSYT01_3 reconstructs a symmetric indefinite matrix A from its block L*D*L' or U*D*U' factorization computed by DSYTRF_RK (or DSYTRF_BK) and computes the residual

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

where C is the reconstructed matrix and EPS is the machine epsilon. That’s the whole job, no cap. 🔥

📝 Parameters 📝

🌈 UPLO 🌈

UPLO is CHARACTER*1. It 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). Diagonal of the block diagonal matrix D and factors U or L as computed by DSYTRF_RK and DSYTRF_BK:

• a) ONLY diagonal elements of the symmetric block diagonal matrix D on the diagonal of A, i.e. D(k,k) = A(k,k); (superdiagonal (or subdiagonal) elements of D should be provided on entry in array E), and
• b) If UPLO = 'U': factor U in the superdiagonal part of A. If UPLO = 'L': factor L in the subdiagonal part of A.

🍓 LDAFAC 🍓

LDAFAC is INTEGER. The leading dimension of the array AFAC. LDAFAC >= max(1,N).

🧚 E 🧚

E is DOUBLE PRECISION array, dimension (N). On entry, contains the superdiagonal (or subdiagonal) elements of the symmetric block diagonal matrix D with 1-by-1 or 2-by-2 diagonal blocks, where

• If UPLO = 'U': E(i) = D(i-1,i),i=2:N, E(1) not referenced;
• If UPLO = 'L': E(i) = D(i+1,i),i=1:N-1, E(N) not referenced.

🔥 IPIV 🔥

IPIV is INTEGER array, dimension (N). The pivot indices from DSYTRF_RK (or DSYTRF_BK).

🌈 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 138 of file dsyt01_3.f.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

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And that’s the tea from LAPACK Version 3.12.0, source path /home/abui.../dsyt01_3.f(3) — bye bestie, go slay those LAPACK tests! 💅✨