TESTING/LIN/cgtt02.f(3)

💅 NAME 💅

TESTING/LIN/cgtt02.f — okay bestie, this page is from the Library Functions Manual, and it’s all about TESTING/LIN/cgtt02.f(3). The function we’re hyping? CGTT02. 💖

🦋 SYNOPSIS 🦋

✨ Functions/Subroutines ✨

       subroutine cgtt02 (trans, n, nrhs, dl, d, du, x, ldx, b, ldb, resid)
           CGTT02

🌸 Function/Subroutine Documentation 🌸

🎀 subroutine cgtt02 🎀

       subroutine cgtt02 (character trans, integer n, integer nrhs, complex,
           dimension( * ) dl, complex, dimension( * ) d, complex, dimension( * )
           du, complex, dimension( ldx, * ) x, integer ldx, complex, dimension(
           ldb, * ) b, integer ldb, real resid)
           CGTT02

🔥 Purpose 🔥

okay so CGTT02 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. That’s the whole glow-up. ✨

💖 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)
• 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 COMPLEX array, dimension (N-1). The (n-1) sub-diagonal elements of A.
• D — D is COMPLEX array, dimension (N). The diagonal elements of A.
• DU — DU is COMPLEX array, dimension (N-1). The (n-1) super-diagonal elements of A.
• X — X is COMPLEX 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 COMPLEX 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 122 of file cgtt02.f.

👑 Author ✨

Generated automatically by Doxygen for LAPACK from the source code.

---

okay bestie, that’s the whole page — from LAPACK, Version 3.12.0, for TESTING/LIN/cgtt02.f(3). 💖✨