STPTRI(3)

🦋 STPTRI(3) — Library Functions Manual 🦋

okay so bestie, this is the Library Functions Manual page for /home/abui...RC/stptri.f(3). It’s giving very specific LAPACK energy, and the main file path is right below. no cap, every detail is staying.

🌸 NAME 🌸

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

✨ SYNOPSIS ✨

Functions/Subroutines

• subroutine STPTRI (uplo, diag, n, ap, info) — STPTRI

📚 Function/Subroutine Documentation 📚

subroutine STPTRI (character uplo, character diag, integer n, real,
    dimension( * ) ap, integer info)

STPTRI

🎯 Purpose

STPTRI computes the inverse of a real upper or lower triangular matrix A stored in packed format.

🧩 Parameters

UPLO

UPLO is CHARACTER*1

• = 'U': A is upper triangular;
• = 'L': A is lower triangular.

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.

AP

AP is REAL array, dimension (N*(N+1)/2)

On entry, the upper or lower triangular matrix A, stored 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.

See below for further details. On exit, the (triangular) inverse of the original matrix, in the same packed storage format.

INFO

INFO is INTEGER

• = 0: successful exit
• < 0: if INFO = -i, the i-th argument had an illegal value
• > 0: if INFO = i, A(i,i) is exactly zero. The triangular matrix is singular and its inverse can not be computed.

👑 Author

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

🔍 Further Details:

A triangular matrix A can be transferred to packed storage using one of the following program segments:

!>  A triangular matrix A can be transferred to packed storage using one
!>  of the following program segments:
!>
!>  UPLO = 'U':                      UPLO = 'L':
!>
!>        JC = 1                           JC = 1
!>        DO 2 J = 1, N                    DO 2 J = 1, N
!>           DO 1 I = 1, J                    DO 1 I = J, N
!>              AP(JC+I-1) = A(I,J)              AP(JC+I-J) = A(I,J)
!>      1    CONTINUE                    1    CONTINUE
!>           JC = JC + J                      JC = JC + N - J + 1
!>      2 CONTINUE                       2 CONTINUE

Definition at line 116 of file stptri.f.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

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final sign-off: this page is from LAPACK, Version 3.12.0, and the footer path is /home/abui...RC/stptri.f(3). The page shows no date, bestie — but the source version is right there 💅✨