CLANTP(3)

💅 CLANTP(3) — LAPACK Library Functions Manual

🎀 NAME

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/clantp.f — bestie, the NAME section is literally just this path. No cap, it’s giving “path is the whole personality.” 💀

---

✨ SYNOPSIS

🦋 Functions/Subroutines

real function CLANTP (norm, uplo, diag, n, ap, work)
    CLANTP 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.

---

🫶 Function/Subroutine Documentation

Okay so here’s the actual signature, and yes, every type and argument is important:

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

CLANTP 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. Periodt. 💅

🎯 Purpose:

Literally the whole point: CLANTP 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. That’s the vibe, that’s the job. ✨

🌈 Returns

CLANTP hands back one of these, depending on NORM:

!>
!>    CLANTP = ( 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. That’s a real caveat, bestie — don’t @ me.

🎀 Parameters

• NORM — CHARACTER*1. Specifies the value to be returned in CLANTP as described above.
• UPLO — CHARACTER*1. Specifies whether the matrix A is upper or lower triangular: = 'U': Upper triangular; = 'L': Lower triangular.
• DIAG — CHARACTER*1. Specifies whether or not the matrix A is unit triangular: = 'N': Non-unit triangular; = 'U': Unit triangular.
• N — INTEGER. The order of the matrix A. N >= 0. When N = 0, CLANTP is set to zero.
• AP — 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)*(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.
• WORK — REAL array, dimension (MAX(1,LWORK)), where LWORK >= N when NORM = 'I'; otherwise, WORK is not referenced.

👑 Author

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

📌 Definition at line 124 of file clantp.f.

🪄 Author

Generated automatically by Doxygen for LAPACK from the source code. Iconic, honestly. 🫶

---

— LAPACK Version 3.12.0 • source /home/abui...RC/clantp.f(3) • date: not listed in this footer, bestie 💖