SSPT01(3)

💅 SSPT01(3) — Library Functions Manual ✨

okay bestie, this is SSPT01(3) from the Library Functions Manual, and it's giving "LAPACK test routine with main character energy." No cap, every detail is still here — we're just making it cute. 💖

🌸 NAME

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/sspt01.f

That's the file, periodt. It's the SSPT01 routine page, and yes, the path is long enough to need its own emotional support water bottle. 😭

✨ SYNOPSIS

🌈 Functions/Subroutines

   Functions/Subroutines
       subroutine SSPT01 (uplo, n, a, afac, ipiv, c, ldc, rwork, resid)
           SSPT01

🧚 Function/Subroutine Documentation

   subroutine SSPT01 (character uplo, integer n, real, dimension( * ) a, real,
       dimension( * ) afac, integer, dimension( * ) ipiv, real, dimension( ldc,
       * ) c, integer ldc, real, dimension( * ) rwork, real resid)
       SSPT01

🫶 Purpose

This is the "reconstruct and check" moment. SSPT01 reconstructs a symmetric indefinite packed matrix A from its block L*D*L' or U*D*U' factorization and computes the residual. The residual formula is exactly:

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

where C is the reconstructed matrix and EPS is the machine epsilon. So it's literally comparing the reconstructed glow-up to the original and checking how close it is. 💅

💖 Parameters

• UPLO — CHARACTER*1. Specifies whether the upper or lower triangular part of the symmetric matrix A is stored: = 'U': upper triangular; = 'L': lower triangular.
• N — INTEGER. The number of rows and columns of the matrix A. N >= 0.
• A — REAL array, dimension (N*(N+1)/2). The original symmetric matrix A, stored as a packed triangular matrix.
• AFAC — REAL array, dimension (N*(N+1)/2). The factored form of the 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 SSPTRF.
• IPIV — INTEGER array, dimension (N). The pivot indices from SSPTRF.
• C — REAL array, dimension (LDC,N).
• LDC — INTEGER. The leading dimension of the array C. LDC >= max(1,N).
• RWORK — REAL array, dimension (N).
• RESID — REAL. 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 109 of file sspt01.f.

⭐ Author

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💖 cute sign-off: this whole icon is from LAPACK, Version 3.12.0, and the footer path situation is /home/abui...IN/sspt01.f(3). mwah! 🎀