DGTT02(3)

💖 NAME 💖

okay so this is DGTT02(3), bestie — LAPACK Library Functions Manual energy. The source page is literally this exact path:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/dgtt02.f

✨ SYNOPSIS ✨

Functions/Subroutines

subroutine DGTT02 (trans, n, nrhs, dl, d, du, x, ldx, b, ldb, resid)

DGTT02 — main character behavior.

🫶 Function/Subroutine Documentation 🫶

subroutine DGTT02 (character trans, integer n, integer nrhs, double
precision, dimension( * ) dl, double precision, dimension( * ) d, double
precision, dimension( * ) du, double precision, dimension( ldx, * ) x,
integer ldx, double precision, dimension( ldb, * ) b, integer ldb,
double precision resid)

DGTT02 (yes, again, slay).

🎀 Purpose 🎀

DGTT02 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.

🌸 Parameters 🌸

• TRANS — CHARACTER. 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 — INTEGER. The order of the matrix A. N >= 0.
• NRHS — INTEGER. The number of right hand sides, i.e., the number of columns of the matrices B and X. NRHS >= 0.
• DL — DOUBLE PRECISION array, dimension (N-1). The (n-1) sub-diagonal elements of A.
• D — DOUBLE PRECISION array, dimension (N). The diagonal elements of A.
• DU — DOUBLE PRECISION array, dimension (N-1). The (n-1) super-diagonal elements of A.
• X — DOUBLE PRECISION array, dimension (LDX,NRHS). The computed solution vectors X.
• LDX — INTEGER. The leading dimension of the array X. LDX >= max(1,N).
• B — DOUBLE PRECISION 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 — INTEGER. The leading dimension of the array B. LDB >= max(1,N).
• RESID — DOUBLE PRECISION. 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 dgtt02.f.

🦋 Author 🦋

Generated automatically by Doxygen for LAPACK from the source code.

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LAPACK Version 3.12.0, source page /home/abui...IN/dgtt02.f(3) — the footer didn’t show a date, so no fake date, bestie 😭💖🫶