CSPCON(3)

cspcon.f(3) 💅

okay so welcome to the Library Functions Manual, bestie — this page is lowkey all about /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/cspcon.f and it is giving “I estimate condition numbers and I know it.” ✨

🌸 NAME 🌸

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

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

   subroutine CSPCON (uplo, n, ap, ipiv, anorm, rcond, work, info)
           CSPCON

🫶 Function/Subroutine Documentation 🫶

   subroutine CSPCON (character uplo, integer n, complex, dimension( * ) ap,
       integer, dimension( * ) ipiv, real anorm, real rcond, complex,
       dimension( * ) work, integer info)
       CSPCON

🎯 Purpose 🎯

okay so CSPCON estimates the reciprocal of the condition number (in the 1-norm) of a complex symmetric packed matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by CSPTRF. periodt.

An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))). the way that formula just sits there? iconic. 💖

💅 Parameters 💅

UPLO

• UPLO is CHARACTER*1
• Specifies whether the details of the factorization are stored as an upper or lower triangular matrix.
• = 'U': Upper triangular, form is A = U*D*U**T;
• = 'L': Lower triangular, form is A = L*D*L**T.

N

• N is INTEGER
• The order of the matrix A. N >= 0.

AP

• AP is COMPLEX array, dimension (N*(N+1)/2)
• The block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by CSPTRF, stored as a packed triangular matrix.

IPIV

• IPIV is INTEGER array, dimension (N)
• Details of the interchanges and the block structure of D as determined by CSPTRF.

ANORM

• ANORM is REAL
• The 1-norm of the original matrix A.

RCOND

• RCOND is REAL
• The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an estimate of the 1-norm of inv(A) computed in this routine.

WORK

• WORK is COMPLEX array, dimension (2*N)

INFO

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

👑 Author 👑

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 117 of file cspcon.f.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

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and that’s the footer vibe, bestie: LAPACK Version 3.12.0, /home/abui...RC/cspcon.f(3), auto-generated and honestly slaying in the most manual-page way possible 💖✨