CTRTTP(3)

🦋 CTRTTP(3) — like, the Library Functions Manual bestie 🦋

okay so this is a page from the Library Functions Manual, and the file it lives in is literally:

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

no cap, that's the whole path 💅

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✨ NAME ✨

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

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🌸 SYNOPSIS 🌸

Functions/Subroutines

• subroutine CTRTTP (uplo, n, a, lda, ap, info) — CTRTTP copies a triangular matrix from the standard full format (TR) to the standard packed format (TP). slay.

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🎀 Function/Subroutine Documentation 🎀

subroutine CTRTTP (character uplo, integer n, complex, dimension( lda, * )
    a, integer lda, complex, dimension( * ) ap, integer info)

CTRTTP copies a triangular matrix from the standard full format (TR) to the standard packed format (TP). that's it, that's the whole gig 🫶

💖 Purpose: 💖

!>
!> CTRTTP copies a triangular matrix A from full format (TR) to standard
!> packed format (TP).
!>

literally just repackaging your triangle, iconic behaviour honestly 🧚

🌈 Parameters 🌈

• UPLO — bestie, this is CHARACTER*1:

!>          UPLO is CHARACTER*1
!>          = 'U':  A is upper triangular;
!>          = 'L':  A is lower triangular.
!>

• N — this one's an INTEGER:

!>          N is INTEGER
!>          The order of the matrices AP and A.  N >= 0.
!>

• A — a COMPLEX array, dimension (LDA,N). here's the tea:

!>          A is COMPLEX array, dimension (LDA,N)
!>          On entry, the triangular 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.
!>

like, only the triangle that matters gets read, the other half is giving background extra energy 💀

• LDA — INTEGER, the leading dimension of the array A:

!>          LDA is INTEGER
!>          The leading dimension of the array A.  LDA >= max(1,N).
!>

• AP — COMPLEX array, dimension ( N*(N+1)/2 ). this is the glow-up destination ✨:

!>          AP is COMPLEX array, dimension ( N*(N+1)/2 ),
!>          On exit, 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)*(2n-j)/2) = A(i,j) for j<=i<=n.
!>

those index formulas are the main character of this whole page, fr fr 🔥

• INFO — INTEGER, the vibe check at the end:

!>          INFO is INTEGER
!>          = 0:  successful exit
!>          < 0:  if INFO = -i, the i-th argument had an illegal value
!>

so 0 means we ate and left no crumbs, and any negative means argument number i was being messy 🙈

👑 Author 👑

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

Definition at line 103 of file ctrttp.f. iykyk 📍

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⭐ Author ⭐

Generated automatically by Doxygen for LAPACK from the source code. not a human, just a very diligent little robot 🎀

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lowkey reminder bestie: LDA >= max(1,N) is not a suggestion, the routine will absolutely notice if you play yourself 💅

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okay bye ily, this page was brought to you by LAPACK, Version 3.12.0, living at /home/abui...RC/ctrttp.f(3) — mwah, go pack a triangle 🦋💖🌸