Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

Contents

p?ptsv

Syntax

Solves a symmetric or Hermitian positive definite tridiagonal system of linear equations.
void
psptsv
(
MKL_INT
*n
,
MKL_INT
*nrhs
,
float
*d
,
float
*e
,
MKL_INT
*ja
,
MKL_INT
*desca
,
float
*b
,
MKL_INT
*ib
,
MKL_INT
*descb
,
float
*work
,
MKL_INT
*lwork
,
MKL_INT
*info
);
void
pdptsv
(
MKL_INT
*n
,
MKL_INT
*nrhs
,
double
*d
,
double
*e
,
MKL_INT
*ja
,
MKL_INT
*desca
,
double
*b
,
MKL_INT
*ib
,
MKL_INT
*descb
,
double
*work
,
MKL_INT
*lwork
,
MKL_INT
*info
);
void
pcptsv
(
char
*uplo
,
MKL_INT
*n
,
MKL_INT
*nrhs
,
float
*d
,
MKL_Complex8
*e
,
MKL_INT
*ja
,
MKL_INT
*desca
,
MKL_Complex8
*b
,
MKL_INT
*ib
,
MKL_INT
*descb
,
MKL_Complex8
*work
,
MKL_INT
*lwork
,
MKL_INT
*info
);
void
pzptsv
(
char
*uplo
,
MKL_INT
*n
,
MKL_INT
*nrhs
,
double
*d
,
MKL_Complex16
*e
,
MKL_INT
*ja
,
MKL_INT
*desca
,
MKL_Complex16
*b
,
MKL_INT
*ib
,
MKL_INT
*descb
,
MKL_Complex16
*work
,
MKL_INT
*lwork
,
MKL_INT
*info
);
Include Files
  • mkl_scalapack.h
Description
The
p?ptsv
function
solves a system of linear equations
A
(1:
n
,
ja
:
ja
+
n
-1)*
X
 =
B
(
ib
:
ib
+
n
-1, 1:
nrhs
)
,
where
A
(1:
n
,
ja
:
ja
+
n
-1)
 is an
n
-by-
n
 real tridiagonal symmetric positive definite distributed matrix.
Cholesky factorization is used to factor a reordering of the matrix into
L*L'
.
Product and Performance Information
Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.
Notice revision #20201201
Input Parameters
n
(global) The order of matrix
A
(
n
≥
 0)
.
nrhs
(global) The number of right-hand sides; the number of columns of the distributed submatrix
B
(
nrhs
≥
 0)
.
d
(local)
Pointer to local part of global vector storing the main diagonal of the matrix.
e
(local)
Pointer to local part of global vector storing the upper diagonal of the matrix. Globally,
du
(n)
 is not referenced, and
du
 must be aligned with
d
.
ja
(global) The index in the global matrix
A
 indicating the start of the matrix to be operated on (which may be either all of
A
 or a submatrix of
A
).
desca
(global and local) array of size
dlen
.
If
1
d
 type (
dtype_a
=501 or 502)
,
dlen
 ≥ 7
;
If
2
d
 type (
dtype_a
=1)
,
dlen
 ≥ 9
.
The array descriptor for the distributed matrix
A
.
Contains information of mapping of
A
 to memory.
b
(local)
Pointer into the local memory to an array of local lead size
lld_b
 ≥
nb
.
On entry, this array contains the local pieces of the right hand sides
B
(
ib
:
ib
+
n
-1, 1:
nrhs
)
.
ib
(global) The row index in the global matrix
B
 indicating the first row of the matrix to be operated on (which may be either all of
b
 or a submatrix of
B
).
descb
(global and local) array of size
dlen
.
If
1
d
 type (
dtype_b
 = 502)
,
dlen
 ≥ 7
;
If
2
d
 type (
dtype_b
 = 1)
,
dlen
 ≥ 9
.
The array descriptor for the distributed matrix
B
.
Contains information of mapping of
B
 to memory.
work
(local).
Temporary workspace. This space may be overwritten in between calls to
functions
.
work
 must be the size given in
lwork
.
lwork
(local or global) Size of user-input workspace
work
. If
lwork
 is too small, the minimal acceptable size will be returned in
work
[0]
 and an error code is returned.
lwork
 > (12*
NPCOL
+3*
nb
)+
max
((10+2*min(100,
nrhs
))*
NPCOL
+4*
nrhs
, 8*
NPCOL
)
.
Output Parameters
d
On exit, this array contains information containing the factors of the matrix. Must be of size greater than or equal to
desca
[
nb
_ - 1]
.
e
On exit, this array contains information containing the factors of the matrix. Must be of size greater than or equal to
desca
[
nb
_ - 1]
.
b
On exit, this contains the local piece of the solutions distributed matrix
X
.
work
On exit,
work
[0]
 contains the minimal
lwork
.
info
(local) If
info
=0
, the execution is successful.
< 0
: If the
i
-th argument is an array and the
j
-entry had an illegal value, then
info
 = -(
i
*100+
j
)
, if the
i
-th argument is a scalar and had an illegal value, then
info
 = -
i
.
> 0
: If
info
 =
k
 ≤
NPROCS
, the submatrix stored on processor
info
 and factored locally was not positive definite, and the factorization was not completed.
If
info
 =
k
 >
NPROCS
, the submatrix stored on processor
info
-
NPROCS
 representing interactions with other processors was not positive definite, and the factorization was not completed.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.