CPTT02(3)

okay so this is the cptt02.f(3) page, and yes bestie, it's from the Library Functions Manual 💅✨

💖 NAME 💖

the name block is literally this path, no edits, no renaming, no cap:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/cptt02.f

✨ SYNOPSIS ✨

Functions/Subroutines 🧚

• subroutine CPTT02 (uplo, n, nrhs, d, e, x, ldx, b, ldb, resid) — CPTT02, that's the whole vibe.

🛠️ Function/Subroutine Documentation 🛠️

here's the full signature, copied exactly:

subroutine CPTT02 (character uplo, integer n, integer nrhs, real, dimension(
       * ) d, complex, dimension( * ) e, complex, dimension( ldx, * ) x,
       integer ldx, complex, dimension( ldb, * ) b, integer ldb, real resid)

CPTT02 — yep, same main character energy, same exact name 😌

Purpose 💡

CPTT02 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. lowkey iconic.

Parameters 🎀

• UPLO — UPLO is CHARACTER*1, and it specifies whether the superdiagonal or the subdiagonal of the tridiagonal matrix A is stored. The values are: = 'U': E is the superdiagonal of A; = 'L': E is the subdiagonal of A. those are the only two, periodt.
• N — N is INTEGER, and it's 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. Also, NRHS >= 0. bestie, keep it non-negative.
• D — D is REAL array, dimension (N), and it holds the n diagonal elements of the tridiagonal matrix A.
• E — E is COMPLEX array, dimension (N-1), and it holds the (n-1) subdiagonal elements of the tridiagonal matrix A.
• X — X is COMPLEX array, dimension (LDX,NRHS), the n by nrhs matrix of solution vectors X.
• LDX — LDX is INTEGER, the leading dimension of the array X. And LDX >= max(1,N). no skipping that check 💅
• B — B is COMPLEX array, dimension (LDB,NRHS). On entry, it's the n by nrhs matrix of right hand side vectors B. On exit, B is overwritten with the difference B - A*X. yes, it gets changed, so don't act surprised.
• LDB — LDB is INTEGER, the leading dimension of the array B. And LDB >= max(1,N). same energy as LDX, fr fr.
• RESID — RESID is REAL, and it equals 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 114 of file cptt02.f.

Author ✨

Generated automatically by Doxygen for LAPACK from the source code.

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okay bestie, cute sign-off time 💖 the footer's source/version situation is LAPACK, Version 3.12.0, and the path /home/abui...IN/cptt02.f(3) — no separate date printed, just those footer bits. slay and goodbye 🎀