DTPCON(3)

okay so this is DTPCON(3), bestie — Library Functions Manual energy 💅✨ (header path: /home/abui...RC/dtpcon.f(3)), and it’s giving linear algebra main character.

💖 NAME 💖

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

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

subroutine DTPCON (norm, uplo, diag, n, ap, rcond, work, iwork, info)
    DTPCON

🫶 Function/Subroutine Documentation 🫶

subroutine DTPCON (character norm, character uplo, character diag, integer
    n, double precision, dimension( * ) ap, double precision rcond, double
    precision, dimension( * ) work, integer, dimension( * ) iwork, integer
    info)
    DTPCON

🎀 Purpose 🎀

DTPCON estimates the reciprocal of the condition number of a packed triangular matrix A, in either the 1-norm or the infinity-norm. No cap.

The norm of A is computed and an estimate is obtained for norm(inv(A)), then the reciprocal of the condition number is computed as:

RCOND = 1 / ( norm(A) * norm(inv(A)) ).

🌸 Parameters 🌸

• NORM — NORM is CHARACTER*1. It specifies whether the 1-norm condition number or the infinity-norm condition number is required:
  • = '1' or 'O': 1-norm;
  • = 'I': Infinity-norm.
• 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 DOUBLE PRECISION 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.
  • If DIAG = 'U', the diagonal elements of A are not referenced and are assumed to be 1.
• RCOND — RCOND is DOUBLE PRECISION. The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(norm(A) * norm(inv(A))).
• WORK — WORK is DOUBLE PRECISION array, dimension (3*N).
• IWORK — IWORK is INTEGER array, dimension (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 128 of file dtpcon.f.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

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