CTPTRS(3)

CTPTRS(3) 💅✨

okay bestie, welcome to the CTPTRS(3) manual page from the Library Functions Manual — yes, manual name folded in near the top like a cute little header bow. 🎀 This is the LAPACK page for the CTPTRS subroutine, and the source file path is right below. No cap.

✨ NAME ✨

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/ctptrs.f

That's literally the whole NAME section — it's giving “the file is the name” energy. 💀 But also: this is the manual for CTPTRS(3), and CTPTRS is the main character here.

🎀 SYNOPSIS 🎀

Functions/Subroutines

       subroutine CTPTRS (uplo, trans, diag, n, nrhs, ap, b, ldb, info)
           CTPTRS

💅 Function/Subroutine Documentation 💅

   subroutine CTPTRS (character uplo, character trans, character diag, integer
       n, integer nrhs, complex, dimension( * ) ap, complex, dimension( ldb, *
       ) b, integer ldb, integer info)
       CTPTRS

🌸 Purpose 🌸

okay so CTPTRS solves a triangular system of the form

A * X = B,  A**T * X = B,  or  A**H * X = B,

where A is a triangular matrix of order N stored in packed format, and B is an N-by-NRHS matrix. It also does a check to verify that A is nonsingular — like a vibe check, but for your matrix. ✨

🦋 Parameters 🦋

💖 UPLO

• UPLO is CHARACTER*1 — tells us which triangle A is:
  • = 'U': A is upper triangular;
  • = 'L': A is lower triangular.

💖 TRANS

• TRANS is CHARACTER*1 — specifies the form of the system of equations:
  • = 'N': A * X = B (No transpose)
  • = 'T': A**T * X = B (Transpose)
  • = 'C': A**H * X = B (Conjugate transpose)

💖 DIAG

• DIAG is CHARACTER*1 —
  • = 'N': A is non-unit triangular;
  • = 'U': A is unit triangular.

💖 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 matrix B. NRHS >= 0.

💖 AP

• AP is COMPLEX array, dimension (N*(N+1)/2) — the upper or lower triangular matrix A, packed columnwise in a linear array. The j-th column of A is stored in the array AP as follows:

if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
if UPLO = 'L', AP(i + (j-1)*(2*n-j)/2) = A(i,j) for j<=i<=n.

💖 B

• B is COMPLEX array, dimension (LDB,NRHS) — on entry, the right hand side matrix B. On exit, if INFO = 0, the solution matrix X.

💖 LDB

• LDB is INTEGER — the leading dimension of the array B. LDB >= max(1,N).

💖 INFO

• INFO is INTEGER —
  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value
  • > 0: if INFO = i, the i-th diagonal element of A is zero, indicating that the matrix is singular and the solutions X have not been computed.

🫶 Author 🫶

• Univ. of Tennessee
• Univ. of California Berkeley
• Univ. of Colorado Denver
• NAG Ltd.

Definition at line 129 of file ctptrs.f.

🫶 Author 🫶

Generated automatically by Doxygen for LAPACK from the source code.

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💖 sign-off: this page is from LAPACK Version 3.12.0, footer path /home/abui...RC/ctptrs.f(3). Date? The footer didn't print one, so we're not inventing it, bestie — but the version and source path are locked in. Periodt. 🫶✨