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LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
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LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
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| subroutine ztpt06 | ( | double precision | RCOND, |
| double precision | RCONDC, | ||
| character | UPLO, | ||
| character | DIAG, | ||
| integer | N, | ||
| complex*16, dimension( * ) | AP, | ||
| double precision, dimension( * ) | RWORK, | ||
| double precision | RAT | ||
| ) |
ZTPT06
ZTPT06 computes a test ratio comparing RCOND (the reciprocal condition number of the triangular matrix A) and RCONDC, the estimate computed by ZTPCON. Information about the triangular matrix is used if one estimate is zero and the other is non-zero to decide if underflow in the estimate is justified.
| [in] | RCOND | RCOND is DOUBLE PRECISION
The estimate of the reciprocal condition number obtained by
forming the explicit inverse of the matrix A and computing
RCOND = 1/( norm(A) * norm(inv(A)) ). |
| [in] | RCONDC | RCONDC is DOUBLE PRECISION
The estimate of the reciprocal condition number computed by
ZTPCON. |
| [in] | UPLO | UPLO is CHARACTER
Specifies whether the matrix A is upper or lower triangular.
= 'U': Upper triangular
= 'L': Lower triangular |
| [in] | DIAG | DIAG is CHARACTER
Specifies whether or not the matrix A is unit triangular.
= 'N': Non-unit triangular
= 'U': Unit triangular |
| [in] | N | N is INTEGER
The order of the matrix A. N >= 0. |
| [in] | AP | AP is COMPLEX*16 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((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. |
| [out] | RWORK | RWORK is DOUBLE PRECISION array, dimension (N) |
| [out] | RAT | RAT is DOUBLE PRECISION
The test ratio. If both RCOND and RCONDC are nonzero,
RAT = MAX( RCOND, RCONDC )/MIN( RCOND, RCONDC ) - 1.
If RAT = 0, the two estimates are exactly the same. |
1.9.4