TESTING/LIN/sptt02.f(3)

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version 3.12.1 · 2 versions
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🦋 NAME 🦋

okay bestie, this is TESTING/LIN/sptt02.f(3) from the Library Functions Manual, and it's literally all about the Fortran subroutine sptt02. slay 💅

🎀 SYNOPSIS 🎀

🌈 Functions/Subroutines 🌈

  • subroutine sptt02 (n, nrhs, d, e, x, ldx, b, ldb, resid) — SPTT02

💅 Function/Subroutine Documentation 💅

🦋 subroutine sptt02 (integer n, integer nrhs, real, dimension( * ) d, real, dimension( * ) e, real, dimension( ldx, * ) x, integer ldx, real, dimension( ldb, * ) b, integer ldb, real resid) 🦋

SPTT02

🍓 Purpose 🍓

okay so SPTT02 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. periodt ✨

🧚 Parameters 🧚

  • N — N is INTEGER. The order of the matrix A.
  • NRHS — NRHS is INTEGER. The number of right hand sides, i.e., the number of columns of the matrices B and X. NRHS >= 0.
  • D — D is REAL array, dimension (N). The n diagonal elements of the tridiagonal matrix A.
  • E — E is REAL array, dimension (N-1). The (n-1) subdiagonal elements of the tridiagonal matrix A.
  • X — X is REAL array, dimension (LDX,NRHS). The n by nrhs matrix of solution vectors X.
  • LDX — LDX is INTEGER. The leading dimension of the array X. LDX >= max(1,N).
  • B — B is REAL 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 — LDB is INTEGER. The leading dimension of the array B. LDB >= max(1,N).
  • RESID — RESID is REAL. norm(B - A*X) / (norm(A) * norm(X) * EPS).

👑 Author 👑

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

📌 Definition at line 103 of file sptt02.f. 📌

💖 Author 💖

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okay bye bestie 🫶 the footer stamp is LAPACK, Version 3.12.0, TESTING/LIN/sptt02.f(3) — mwah 💋✨🎀

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