SPTT02(3)

📦 version 3.12.0, in opensuse-leap 16.0

okay bestie, welcome to sptt02.f(3) in the Library Functions Manual — yes, the manual name is folded in right here instead of copying that weird header line. This is the page for the Fortran file and its routine, and it's lowkey iconic.

🌸 NAME 🌸

This page is for the Fortran file at:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/sptt02.f

✨ 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. slay, that's the whole purpose 💅

🌈 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 👑

Generated automatically by Doxygen for LAPACK from the source code.

okay that's the whole page bestie — the footer source/version sign-off is LAPACK Version 3.12.0 and /home/abui...IN/sptt02.f(3), so take that and go slay your linear algebra 💋✨

📦 where this page comes from