TESTING/LIN/cppt01.f(3)

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version 3.12.1 · 2 versions
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🎀 NAME

hey bestie, welcome to the Library Functions Manual page for TESTING/LIN/cppt01.f(3) — the title is TESTING/LIN/cppt01.f, and it is literally all about the cppt01 subroutine. 💅

✨ SYNOPSIS

🧚 Functions/Subroutines

subroutine cppt01 (uplo, n, a, afac, rwork, resid)
    CPPT01

💅 Function/Subroutine Documentation

subroutine cppt01 (character uplo, integer n, complex, dimension( * ) a,
       complex, dimension( * ) afac, real, dimension( * ) rwork, real resid)
    CPPT01

the function name is CPPT01, no cap. 🫶

🌸 Purpose

okay so here’s the tea, fr fr: CPPT01 reconstructs a Hermitian positive definite packed matrix A from its L*L' or U'*U factorization and computes the residual:

   norm( L*L' - A ) / ( N * norm(A) * EPS ) or
   norm( U'*U - A ) / ( N * norm(A) * EPS ),

where EPS is the machine epsilon, L' is the conjugate transpose of L, and U' is the conjugate transpose of U. the Doxygen comment wrappers are all !>, but the real content is that math right there. ✨

🍓 Parameters

  • UPLO — UPLO is CHARACTER*1. Specifies whether the upper or lower triangular part of the Hermitian 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 COMPLEX array, dimension (N*(N+1)/2). The original Hermitian matrix A, stored as a packed triangular matrix.
  • AFAC — AFAC is COMPLEX array, dimension (N*(N+1)/2). On entry, the factor L or U from the L*L' or U'*U factorization of A, stored as a packed triangular matrix. Overwritten with the reconstructed matrix, and then with the difference L*L' - A (or U'*U - A).
  • RWORK — RWORK is REAL array, dimension (N).
  • RESID — RESID is REAL.
    • If UPLO = 'L', norm(L*L' - A) / ( N * norm(A) * EPS )
    • If UPLO = 'U', norm(U'*U - A) / ( N * norm(A) * EPS )

👑 Author

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

Definition at line 94 of file cppt01.f.

🫶 Author

Generated automatically by Doxygen for LAPACK from the source code.

Final sign-off, bestie: this is LAPACK Version 3.12.0, page TESTING/LIN/cppt01.f(3). The footer does not give a date, so there’s no date to spill — just version and page, periodt. 🫶✨

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