TESTING/LIN/cptt02.f(3)

💅 NAME 💅

okay bestie, this is the Library Functions Manual page for TESTING/LIN/cptt02.f — yes, the manual name is folded right into the intro because we are not copy-pasting the header line, we are living it. It's the home of the CPTT02 routine, and we're gonna get into every last parameter. 🫶

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

       subroutine cptt02 (uplo, n, nrhs, d, e, x, ldx, b, ldb, resid)
           CPTT02

👑 Function/Subroutine Documentation 👑

💫 CPTT02 💫

   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

🎀 Purpose 🎀

Okay so the whole purpose is: 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. That's the math, and it ate. 💅

💖 Parameters 💖

• UPLO — is CHARACTER*1. It specifies whether the superdiagonal or the subdiagonal of the tridiagonal matrix A is stored. = 'U': E is the superdiagonal of A. = 'L': E is the subdiagonal of A.
• N — is INTEGER. The order of the matrix A.
• NRHS — is INTEGER. The number of right hand sides, i.e., the number of columns of the matrices B and X. NRHS >= 0.
• D — is REAL array, dimension (N). The n diagonal elements of the tridiagonal matrix A.
• E — is COMPLEX array, dimension (N-1). The (n-1) subdiagonal elements of the tridiagonal matrix A.
• X — is COMPLEX array, dimension (LDX,NRHS). The n by nrhs matrix of solution vectors X.
• LDX — is INTEGER. The leading dimension of the array X. LDX >= max(1,N).
• B — is COMPLEX 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 — is INTEGER. The leading dimension of the array B. LDB >= max(1,N).
• RESID — is REAL. norm(B - A*X) / (norm(A) * norm(X) * EPS)

🌟 Author 🌟

Shoutout to the author squad, no cap:

• 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 that's the whole page, bestie — mwah! 💋 This footer energy is LAPACK, Version 3.12.0, and the page path is TESTING/LIN/cptt02.f(3). 🎀✨