TESTING/LIN/dptt02.f(3)

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version 3.12.1 · 3 versions
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🌸 NAME 🌸

okay bestie, welcome to the Library Functions Manual page for TESTING/LIN/dptt02.f — it's a LAPACK test routine that does a residual check for a symmetric tridiagonal solve. It's giving "trust but verify" energy, and honestly? iconic. 💅

✨ SYNOPSIS ✨

🧚 Functions/Subroutines

  • subroutine dptt02 (n, nrhs, d, e, x, ldx, b, ldb, resid) — DPTT02

🫶 Function/Subroutine Documentation 🫶

   subroutine dptt02 (integer n, integer nrhs, double precision, dimension( * )
       d, double precision, dimension( * ) e, double precision, dimension( ldx,
       * ) x, integer ldx, double precision, dimension( ldb, * ) b, integer
       ldb, double precision resid)
       DPTT02

✨ Purpose ✨

DPTT02 computes the residual for the solution to a symmetric tridiagonal system of equations:

RESID = norm(B - A*X) / (norm(A) * norm(X) * EPS),

where EPS is the machine epsilon. 🎀

🎀 Parameters 🎀

  • N — INTEGER; the order of the matrix A. 👑
  • NRHS — INTEGER; the number of right hand sides, i.e., the number of columns of the matrices B and X. It has to satisfy NRHS >= 0. 🫶
  • D — DOUBLE PRECISION array, dimension (N); the n diagonal elements of the tridiagonal matrix A. ⭐
  • E — DOUBLE PRECISION array, dimension (N-1); the (n-1) subdiagonal elements of the tridiagonal matrix A. 🦋
  • X — DOUBLE PRECISION array, dimension (LDX,NRHS); the n by nrhs matrix of solution vectors X. 💜
  • LDX — INTEGER; the leading dimension of the array X. Needs LDX >= max(1,N). ✨
  • B — DOUBLE PRECISION array, dimension (LDB,NRHS); on entry, the n by nrhs matrix of right hand side vectors B. On exit, B is overwritten with the difference B - A*X. 💖
  • LDB — INTEGER; the leading dimension of the array B. Needs LDB >= max(1,N). 🌈
  • RESID — DOUBLE PRECISION; it's norm(B - A*X) / (norm(A) * norm(X) * EPS). 🔥

👑 Author 👑

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

🦋 Definition 🦋

Definition at line 103 of file dptt02.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code. 🤖

okay bestie, that's the whole page — LAPACK Version 3.12.0, source TESTING/LIN/dptt02.f(3), mwah 💋

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