/home/abui.../cpotrf2.f(3)

okay so bestie, welcome to the Library Functions Manual page for CPOTRF2.f — yes, that exact file. We're folding the manual name in up here instead of copying the header line, because we're cute like that 💅.

🌸 NAME 🌸

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/cpotrf2.f

That's the name, no cap: the Fortran source file for this whole recursive Cholesky moment.

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🦋 SYNOPSIS 🦋

   Functions/Subroutines
       recursive subroutine CPOTRF2 (uplo, n, a, lda, info)
           CPOTRF2

So the subroutine is recursive subroutine CPOTRF2 (uplo, n, a, lda, info), and its little label is CPOTRF2, periodt.

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💜 Function/Subroutine Documentation 💜

Here's the full signature, exactly as it appears:

   recursive subroutine CPOTRF2 (character uplo, integer n, complex, dimension(
       lda, * ) a, integer lda, integer info)
       CPOTRF2

🎀 Purpose 🎀

CPOTRF2 computes the Cholesky factorization of a Hermitian positive definite matrix A using the recursive algorithm.

The factorization has the form:

A = U**H * U,  if UPLO = 'U', or
A = L  * L**H,  if UPLO = 'L',

where U is an upper triangular matrix and L is lower triangular.

This is the recursive version of the algorithm. It divides the matrix into four submatrices:

     [  A11 | A12  ]  where A11 is n1 by n1 and A22 is n2 by n2
A = [ -----|----- ]  with n1 = n/2
     [  A21 | A22  ]       n2 = n-n1

The subroutine calls itself to factor A11. Update and scale A21 or A12, update A22 then calls itself to factor A22.

🌸 Parameters 🌸

• UPLO — is CHARACTER*1. The values are:
  • = 'U': Upper triangle of A is stored;
  • = 'L': Lower triangle of A is stored.
• N — is INTEGER. The order of the matrix A. N >= 0.
• A — is COMPLEX array, dimension (LDA,N). On entry, the Hermitian matrix A. If UPLO = 'U', the leading N-by-N upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If UPLO = 'L', the leading N-by-N lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced.

On exit, if INFO = 0, the factor U or L from the Cholesky factorization A = U**H*U or A = L*L**H.

• LDA — is INTEGER. The leading dimension of the array A. LDA >= max(1,N).
• INFO — is INTEGER. The values are:
  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value
  • > 0: if INFO = i, the leading principal minor of order i is not positive, and the factorization could not be completed.

👑 Author 👑

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

Definition at line 105 of file cpotrf2.f.

👑 Author 👑 (Doxygen's version)

Generated automatically by Doxygen for LAPACK from the source code.

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Sign-off vibe: LAPACK, Version 3.12.0, page /home/abui.../cpotrf2.f(3) — that's the footer energy, mwah 💋✨