TESTING/LIN/sgtt02.f(3)

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version 3.12.1 · 2 versions
, in arch rolling

✨ NAME ✨

okay so bestie, this page is for TESTING/LIN/sgtt02.f — the manual page name is TESTING/LIN/sgtt02.f(3), and it lives in the Library Functions Manual. it's all about the Fortran subroutine sgtt02, no cap 💖

🌸 SYNOPSIS 🌸

🦋 Functions/Subroutines 🦋

subroutine sgtt02 (trans, n, nrhs, dl, d, du, x, ldx, b, ldb, resid)
    SGTT02

🧚 Function/Subroutine Documentation 🧚

subroutine sgtt02 (character trans, integer n, integer nrhs, real,
    dimension( * ) dl, real, dimension( * ) d, real, dimension( * ) du,
    real, dimension( ldx, * ) x, integer ldx, real, dimension( ldb, * ) b,
    integer ldb, real resid)

SGTT02

🎯 Purpose: 🎯

bestie, the whole point is this: SGTT02 computes the residual for the solution to a tridiagonal system of equations:

RESID = norm(B - op(A)*X) / (norm(op(A)) * norm(X) * EPS),
where EPS is the machine epsilon.

the norm used is the 1-norm. periodt. ✨

💅 Parameters 💅

  • TRANS — TRANS is CHARACTER. it specifies the form of the residual:
    • = 'N': B - A * X (No transpose)
    • = 'T': B - A**T * X (Transpose)
    • = 'C': B - A**H * X (Conjugate transpose = Transpose)
  • N — N is INTEGER. the order of the matrix A. N >= 0.
  • NRHS — NRHS is INTEGER. the number of right hand sides, i.e., the number of columns of the matrices B and X. NRHS >= 0.
  • DL — DL is REAL array, dimension (N-1). the (n-1) sub-diagonal elements of A.
  • D — D is REAL array, dimension (N). the diagonal elements of A.
  • DU — DU is REAL array, dimension (N-1). the (n-1) super-diagonal elements of A.
  • X — X is REAL array, dimension (LDX,NRHS). the computed 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 right hand side vectors for the system of linear equations. on exit, B is overwritten with the difference B - op(A)*X.
  • LDB — LDB is INTEGER. the leading dimension of the array B. LDB >= max(1,N).
  • RESID — RESID is REAL. norm(B - op(A)*X) / (norm(op(A)) * norm(X) * EPS).

👑 Author 👑

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

Definition at line 123 of file sgtt02.f.

🌈 Author 🌈

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bye bestie 💖 this iconic page is source/version LAPACK / Version 3.12.0, and the manual page is TESTING/LIN/sgtt02.f(3). slay. 🎀

📦 where this page comes from