DSPT01(3)

💅 DSPT01(3) — Library Functions Manual energy 💅

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🌸 NAME 🌸

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/dspt01.f

That’s the file this page is about — the DSPT01 source, periodt. 🎀

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🦋 SYNOPSIS 🦋

✨ Functions/Subroutines ✨

subroutine DSPT01 (uplo, n, a, afac, ipiv, c, ldc, rwork, resid)
DSPT01

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💅 Function/Subroutine Documentation 💅

Here’s the full signature with all the types and dimensions, bestie — do not lose a single character:

subroutine DSPT01 (character uplo, integer n, double precision, dimension( * ) a, double precision, dimension( * ) afac, integer, dimension( * ) ipiv, double precision, dimension( ldc, * ) c, integer ldc, double precision, dimension( * ) rwork, double precision resid)
DSPT01

🎀 Purpose 🎀

DSPT01 reconstructs a symmetric indefinite packed 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. slay. ✨

🍓 Parameters 🍓

• UPLO — UPLO is CHARACTER*1 and tells us which triangle of the symmetric matrix A is stored:
  • = 'U': Upper triangular
  • = 'L': Lower triangular
• N — N is INTEGER. It’s the number of rows and columns of matrix A. N >= 0.
• A — A is DOUBLE PRECISION array, dimension (N*(N+1)/2). It’s the original symmetric matrix A, stored as a packed triangular matrix.
• AFAC — AFAC is DOUBLE PRECISION array, dimension (N*(N+1)/2). It’s the factored form of matrix A, stored as a packed triangular matrix. 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 DSPTRF.
• IPIV — IPIV is INTEGER array, dimension (N). It’s the pivot indices from DSPTRF.
• C — C is DOUBLE PRECISION array, dimension (LDC,N).
• LDC — LDC is INTEGER. It’s the leading dimension of array C. LDC >= max(1,N).
• RWORK — RWORK is DOUBLE PRECISION array, dimension (N).
• RESID — RESID is DOUBLE PRECISION. If UPLO = 'L', it’s norm(L*D*L' - A) / ( N * norm(A) * EPS ). If UPLO = 'U', it’s norm(U*D*U' - A) / ( N * norm(A) * EPS ).

👑 Author 👑

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

these legends wrote it, iykyk. 🫶

Definition at line 109 of file dspt01.f.

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🧚 Author 🧚

Generated automatically by Doxygen for LAPACK from the source code.

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