ZTPT01(3)

🌸 NAME 🌸

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/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/ztpt01.f

no cap, that’s the whole NAME section 🫶

✨ SYNOPSIS ✨

Functions/Subroutines

subroutine ZTPT01 (uplo, diag, n, ap, ainvp, rcond, rwork, resid)
    ZTPT01

💅 Function/Subroutine Documentation 💅

subroutine ZTPT01 (character uplo, character diag, integer n, complex*16,
       dimension( * ) ap, complex*16, dimension( * ) ainvp, double precision
       rcond, double precision, dimension( * ) rwork, double precision resid)
       ZTPT01

Purpose:

ZTPT01 is out here computing the residual for a triangular matrix A times its inverse when A is stored in packed format. The formula is giving:

RESID = norm(A*AINV - I) / ( N * norm(A) * norm(AINV) * EPS ),

where EPS is the machine epsilon 💅

Parameters

UPLO

UPLO is CHARACTER*1. It says whether the matrix A is upper or lower triangular:

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

DIAG

DIAG is CHARACTER*1. It says 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.

AP

AP is COMPLEX*16 array, dimension (N*(N+1)/2). The original 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((j-1)*j/2 + i) = A(i,j) for 1<=i<=j;
if UPLO = 'L',
   AP((j-1)*(n-j) + j*(j+1)/2 + i-j) = A(i,j) for j<=i<=n.

AINVP

AINVP is COMPLEX*16 array, dimension (N*(N+1)/2). On entry, the (triangular) inverse of the matrix A, packed columnwise in a linear array as in AP. On exit, the contents of AINVP are destroyed 💀

RCOND

RCOND is DOUBLE PRECISION. The reciprocal condition number of A, computed as 1/(norm(A) * norm(AINV)).

RWORK

RWORK is DOUBLE PRECISION array, dimension (N).

RESID

RESID is DOUBLE PRECISION. norm(A*AINV - I) / ( N * norm(A) * norm(AINV) * EPS ).

Author

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

Definition at line 108 of file ztpt01.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

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