p?trsv
p?trsv
Solves a system of linear equations whose coefficients are in a distributed triangular matrix.
Syntax
void pstrsv
(
const char
*uplo
,
const char
*trans
,
const char
*diag
,
const MKL_INT
*n
,
const float
*a
,
const MKL_INT
*ia
,
const MKL_INT
*ja
,
const MKL_INT
*desca
,
float
*x
,
const MKL_INT
*ix
,
const MKL_INT
*jx
,
const MKL_INT
*descx
,
const MKL_INT
*incx
);
void pdtrsv
(
const char
*uplo
,
const char
*trans
,
const char
*diag
,
const MKL_INT
*n
,
const double
*a
,
const MKL_INT
*ia
,
const MKL_INT
*ja
,
const MKL_INT
*desca
,
double
*x
,
const MKL_INT
*ix
,
const MKL_INT
*jx
,
const MKL_INT
*descx
,
const MKL_INT
*incx
);
void pctrsv
(
const char
*uplo
,
const char
*trans
,
const char
*diag
,
const MKL_INT
*n
,
const MKL_Complex8
*a
,
const MKL_INT
*ia
,
const MKL_INT
*ja
,
const MKL_INT
*desca
,
MKL_Complex8
*x
,
const MKL_INT
*ix
,
const MKL_INT
*jx
,
const MKL_INT
*descx
,
const MKL_INT
*incx
);
void pztrsv
(
const char
*uplo
,
const char
*trans
,
const char
*diag
,
const MKL_INT
*n
,
const MKL_Complex16
*a
,
const MKL_INT
*ia
,
const MKL_INT
*ja
,
const MKL_INT
*desca
,
MKL_Complex16
*x
,
const MKL_INT
*ix
,
const MKL_INT
*jx
,
const MKL_INT
*descx
,
const MKL_INT
*incx
);
Include Files
- mkl_pblas.h
Description
The
p?trsv
routines solve one of the systems of equations:sub(
, or A
)*sub(x
) = b
sub(
, or A
)'*sub(x
) = b
conjg(sub(
,A
)')*sub(x
) = b
where:
sub(
is a A
)n
-by-n
unit, or non-unit, upper or lower triangular distributed matrix,
sub(
,A
) = A
(ia
:ia
+n
-1, ja
:ja
+n
-1)b
and sub(
are x
)n
-element distributed vectors,sub(
denotes x
)X
(ix
, jx
:jx
+n
-1)incx
= m_x
X
(ix
: ix
+n
-1, jx
)incx
= 1,The routine does not test for singularity or near-singularity. Such tests must be performed before calling this routine.
Input Parameters
- uplo
- (global) Specifies whether the distributed matrixsub(is upper or lower triangular:A)iforuplo='U''u', then the matrix is upper triangular;iforuplo='L''l', then the matrix is low triangular.
- trans
- (global) Specifies the form of the system of equations:ifortransa= 'N'', thenn'sub(;A)*sub(x) =bifortransa= 'T'', thent'sub(;A)'*sub(x) =bifortransa= 'C'', thenc'conjg(sub(.A)')*sub(x) =b
- diag
- (global) Specifies whether the matrixsub(is unit triangular:A)ifordiag='U''u'then the matrix is unit triangular;ifordiag='N''n', then the matrix is not unit triangular.
- n
- (global) Specifies the order of the distributed matrixsub(,A)n≥0.
- a
- (local)Array, size at least(.lld_a, LOCq(1,ja+n-1))Before entry withoruplo='U''u', this array contains the local entries corresponding to the entries of the upper triangular distributed matrixsub(, and the local entries corresponding to the entries of the strictly lower triangular part of the distributed matrixA)sub(is not referenced.A)Before entry withoruplo='L''l', this array contains the local entries corresponding to the entries of the lower triangular distributed matrixsub(, and the local entries corresponding to the entries of the strictly upper triangular part of the distributed matrixA)sub(is not referenced .A)Whenordiag='U''u', the local entries corresponding to the diagonal elements of the submatrixsub(are not referenced either, but are assumed to be unity.A)
- ia,ja
- (global) The row and column indices in the distributed matrixAindicating the first row and the first column of the submatrixsub(, respectively.A)
- desca
- (global and local) array of dimension 9. The array descriptor of the distributed matrixA.
- x
- (local)Array, size at least(.jx-1)*m_x+ix+(n-1)*abs(incx))This array contains the entries of the distributed vectorsub(. Before entry,x)sub(must contain thex)n-element right-hand side distributed vectorb.
- ix,jx
- (global) The row and column indices in the distributed matrixXindicating the first row and the first column of the submatrixsub(, respectively.x)
- descx
- (global and local) array of dimension 9. The array descriptor of the distributed matrixX.
- incx
- (global) Specifies the increment for the elements ofsub(. Only two values are supported, namely 1 andx)m_x.incxmust not be zero.
Output Parameters
- x
- Overwritten with the solution vector.