SRC/zspcon.f(3)

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version 3.12.1 · 4 versions
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💖 SRC/zspcon.f(3) 💖

okay so this is the page for SRC/zspcon.f(3), and the manual name is Library Functions Manual — yes bestie, we're deep in function-reference territory and it's lowkey iconic. 🫶

🌸 NAME 🌸

SRC/zspcon.f

ZSPCON, no cap. 💅

✨ SYNOPSIS ✨

🫶 Functions/Subroutines 🫶

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

ZSPCON. That's the whole vibe. 🎀

🦋 Function/Subroutine Documentation 🦋

🧚 subroutine zspcon 🧚

       subroutine zspcon (character uplo, integer n, complex*16, dimension( * ) ap,
       integer, dimension( * ) ipiv, double precision anorm, double precision
       rcond, complex*16, dimension( * ) work, integer info)

ZSPCON. 💖

💡 Purpose 💡

okay so the whole point: ZSPCON 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 ZSPTRF.

An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).

Literally that's the assignment and it ate. ✨

🌈 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*16 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 ZSPTRF, 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 ZSPTRF.

⭐ ANORM

ANORM is DOUBLE PRECISION.

The 1-norm of the original matrix A.

🔥 RCOND

RCOND is DOUBLE PRECISION.

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*16 array, dimension (2*N).

👑 INFO

INFO is INTEGER.

  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value
bestie, if INFO comes back negative, that's the routine telling you an argument was illegal — periodt. 💀

👑 Author 👑

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

Definition at line 117 of file zspcon.f.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

mwah 💋 xoxo, this cutie came from LAPACK, version 3.12.0, on the SRC/zspcon.f(3) page — and the footer didn't give me a date, so I'm not inventing one, bestie. 💅✨

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