Developer Reference for Intel® oneAPI Math Kernel Library for C
p?ptsv
Syntax
Solves a symmetric or Hermitian positive definite tridiagonal system of linear equations.
voidpsptsv ( 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 );
voidpdptsv ( 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 );
voidpcptsv ( 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 );
voidpzptsv ( 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
psptsv pdptsv pcptsv pzptsv The p?ptsv routine 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) REAL for psptsv DOUBLE PRECISON for pdptsv COMPLEX for pcptsv DOUBLE COMPLEX for pzptsv . Pointer to local part of global vector storing the main diagonal of the matrix.
- e
-
(local) REAL for psptsv DOUBLE PRECISON for pdptsv COMPLEX for pcptsv DOUBLE COMPLEX for pzptsv . 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 1d type (dtype_a=501 or 502) , dlen ≥ 7 ; If 2d type (dtype_a=1) , dlen ≥ 9 . The array descriptor for the distributed matrix A . Contains information of mapping of A to memory.
- b
-
(local) REAL for psptsv DOUBLE PRECISON for pdptsv COMPLEX for pcptsv DOUBLE COMPLEX for pzptsv . 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 1d type (dtype_b = 502) , dlen ≥ 7 ; If 2d type (dtype_b = 1) , dlen ≥ 9 . The array descriptor for the distributed matrix B . Contains information of mapping of B to memory.
- work
-
(local). REAL for psptsv DOUBLE PRECISON for pdptsv COMPLEX for pcptsv DOUBLE COMPLEX for pzptsv .
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(1)[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_)[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_)[nb_ - 1] .
- b
-
On exit, this contains the local piece of the solutions distributed matrix X .
- work
-
On exit, work(1)[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.