SLANTP(3)

💅 NAME

hey bestie, welcome to the slantp.f page from the Library Functions Manual ✨ this whole glow-up is about:

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

---

🌸 SYNOPSIS

🫶 Functions/Subroutines

• real function SLANTP (norm, uplo, diag, n, ap, work) — SLANTP returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a triangular matrix supplied in packed form. it's giving norm main-character energy, no cap 💅

---

🦋 Function/Subroutine Documentation

✨ real function SLANTP

real function SLANTP (character norm, character uplo, character diag,
    integer n, real, dimension( * ) ap, real, dimension( * ) work)

okay so SLANTP returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a triangular matrix supplied in packed form. literally iconic 💖

🎯 Purpose

!>
!> SLANTP  returns the value of the one norm,  or the Frobenius norm, or
!> the  infinity norm,  or the  element of  largest absolute value  of a
!> triangular matrix A, supplied in packed form.
!>

🌈 Returns

SLANTP

!>
!>    SLANTP = ( max(abs(A(i,j))), NORM = 'M' or 'm'
!>             (
!>             ( norm1(A),         NORM = '1', 'O' or 'o'
!>             (
!>             ( normI(A),         NORM = 'I' or 'i'
!>             (
!>             ( normF(A),         NORM = 'F', 'f', 'E' or 'e'
!>
!> where  norm1  denotes the  one norm of a matrix (maximum column sum),
!> normI  denotes the  infinity norm  of a matrix  (maximum row sum) and
!> normF  denotes the  Frobenius norm of a matrix (square root of sum of
!> squares).  Note that  max(abs(A(i,j)))  is not a consistent matrix norm.
!>

bestie, real talk: max(abs(A(i,j))) is not a consistent matrix norm. periodt 🫶

🎀 Parameters

💜 NORM

NORM is CHARACTER*1 — specifies the value to be returned in SLANTP as described above. it's the vibe selector for which norm you're getting ✨

💜 UPLO

UPLO is CHARACTER*1 — specifies whether the matrix A is upper or lower triangular.

• = 'U': Upper triangular
• = 'L': Lower triangular

💜 DIAG

DIAG is CHARACTER*1 — specifies whether or not the matrix A is unit triangular.

• = 'N': Non-unit triangular
• = 'U': Unit triangular

💜 N

N is INTEGER — the order of the matrix A. N >= 0. When N = 0, SLANTP is set to zero. tiny matrix, tiny result, still valid 💅

💜 AP

AP is REAL 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)*(2n-j)/2) = A(i,j) for j<=i<=n.

note that when DIAG = 'U', the elements of the array AP corresponding to the diagonal elements of the matrix A are not referenced, but are assumed to be one. sneaky little diagonal behavior, iykyk 🍓

💜 WORK

WORK is REAL array, dimension (MAX(1,LWORK)), where LWORK >= N when NORM = 'I'; otherwise, WORK is not referenced. so if you're not doing the infinity norm thing, this baby can chill 🧚

👑 Author

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

Definition at line 123 of file slantp.f.

---

🌟 Author

Generated automatically by Doxygen for LAPACK from the source code.

---

that's the whole page, bestie! LAPACK Version 3.12.0 — footer path /home/abui...RC/slantp.f(3) — that's the cute little source/version sign-off 🎀✨💖