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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 ztrt03 | ( | character | uplo, |
| character | trans, | ||
| character | diag, | ||
| integer | n, | ||
| integer | nrhs, | ||
| complex*16, dimension( lda, * ) | a, | ||
| integer | lda, | ||
| double precision | scale, | ||
| double precision, dimension( * ) | cnorm, | ||
| double precision | tscal, | ||
| complex*16, dimension( ldx, * ) | x, | ||
| integer | ldx, | ||
| complex*16, dimension( ldb, * ) | b, | ||
| integer | ldb, | ||
| complex*16, dimension( * ) | work, | ||
| double precision | resid | ||
| ) |
ZTRT03
ZTRT03 computes the residual for the solution to a scaled triangular
system of equations A*x = s*b, A**T *x = s*b, or A**H *x = s*b.
Here A is a triangular matrix, A**T denotes the transpose of A, A**H
denotes the conjugate transpose of A, s is a scalar, and x and b are
N by NRHS matrices. The test ratio is the maximum over the number of
right hand sides of
norm(s*b - op(A)*x) / ( norm(op(A)) * norm(x) * EPS ),
where op(A) denotes A, A**T, or A**H, and EPS is the machine epsilon. | [in] | UPLO | UPLO is CHARACTER*1
Specifies whether the matrix A is upper or lower triangular.
= 'U': Upper triangular
= 'L': Lower triangular |
| [in] | TRANS | TRANS is CHARACTER*1
Specifies the operation applied to A.
= 'N': A *x = s*b (No transpose)
= 'T': A**T *x = s*b (Transpose)
= 'C': A**H *x = s*b (Conjugate transpose) |
| [in] | DIAG | DIAG is CHARACTER*1
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] | NRHS | NRHS is INTEGER
The number of right hand sides, i.e., the number of columns
of the matrices X and B. NRHS >= 0. |
| [in] | A | A is COMPLEX*16 array, dimension (LDA,N)
The triangular matrix A. If UPLO = 'U', the leading n by n
upper triangular part of the array A contains the upper
triangular matrix, and the strictly lower triangular part of
A is not referenced. If UPLO = 'L', the leading n by n lower
triangular part of the array A contains the lower triangular
matrix, and the strictly upper triangular part of A is not
referenced. If DIAG = 'U', the diagonal elements of A are
also not referenced and are assumed to be 1. |
| [in] | LDA | LDA is INTEGER
The leading dimension of the array A. LDA >= max(1,N). |
| [in] | SCALE | SCALE is DOUBLE PRECISION
The scaling factor s used in solving the triangular system. |
| [in] | CNORM | CNORM is DOUBLE PRECISION array, dimension (N)
The 1-norms of the columns of A, not counting the diagonal. |
| [in] | TSCAL | TSCAL is DOUBLE PRECISION
The scaling factor used in computing the 1-norms in CNORM.
CNORM actually contains the column norms of TSCAL*A. |
| [in] | X | X is COMPLEX*16 array, dimension (LDX,NRHS)
The computed solution vectors for the system of linear
equations. |
| [in] | LDX | LDX is INTEGER
The leading dimension of the array X. LDX >= max(1,N). |
| [in] | B | B is COMPLEX*16 array, dimension (LDB,NRHS)
The right hand side vectors for the system of linear
equations. |
| [in] | LDB | LDB is INTEGER
The leading dimension of the array B. LDB >= max(1,N). |
| [out] | WORK | WORK is COMPLEX*16 array, dimension (N) |
| [out] | RESID | RESID is DOUBLE PRECISION
The maximum over the number of right hand sides of
norm(op(A)*x - s*b) / ( norm(op(A)) * norm(x) * EPS ). |
1.9.7