p?tradd

Syntax

Include Files

The C interfaces for this function are specified in the mkl_pblas.h include file.

Description

The p?tradd routines perform sum operation for two distributed triangular matrices. The operation is defined as sub(C):=beta*sub(C) + alpha*op(sub(A)),

where:

op(x) is one of op(x) = x, or op(x) = x', or op(x) = conjg(x').

alpha and beta are scalars,

sub(C) is an m-by-n distributed matrix, sub(C)=C(ic:ic+m-1, jc:jc+n-1).

sub(A) is a distributed matrix, sub(A)=A(ia:ia+n-1, ja:ja+m-1).

Input Parameters

uplo

(global) CHARACTER*1. Specifies whether the distributed matrix sub(C) is upper or lower triangular:

if uplo = 'U' or 'u', then the matrix is upper triangular;

if uplo = 'L' or 'l', then the matrix is low triangular.

trans

(global) CHARACTER*1. Specifies the operation:

if trans = 'N' or 'n', then op(sub(A)) := sub(A);

if trans = 'T' or 't', then op(sub(A)) := sub(A)';

if trans = 'C' or 'c', then op(sub(A)) := conjg(sub(A)').

m

(global) INTEGER. Specifies the number of rows of the distributed matrix sub(C) and the number of columns of the submatrix sub(A), m ≥ 0.

n

(global) INTEGER. Specifies the number of columns of the distributed matrix sub(C) and the number of rows of the submatrix sub(A), n ≥ 0.

alpha

(global) REAL for pstradd

DOUBLE PRECISION for pdtradd

COMPLEX for pctradd

DOUBLE COMPLEX for pztradd

Specifies the scalar alpha.

a

(local) REAL for pstradd

DOUBLE PRECISION for pdtradd

COMPLEX for pctradd

DOUBLE COMPLEX for pztradd

Array, DIMENSION (lld_a, LOCq(ja+m-1)). This array contains the local pieces of the distributed matrix sub(A).

ia, ja

(global) INTEGER. The row and column indices in the distributed matrix A indicating the first row and the first column of the submatrix sub(A), respectively.

desca

(global and local) INTEGER array of dimension 8. The array descriptor of the distributed matrix A.

beta

(global) REAL for pstradd

DOUBLE PRECISION for pdtradd

COMPLEX for pctradd

DOUBLE COMPLEX for pztradd

Specifies the scalar beta.

When beta is equal to zero, then sub(C) need not be set on input.

c

(local) REAL for pstradd

DOUBLE PRECISION for pdtradd

COMPLEX for pctradd

DOUBLE COMPLEX for pztradd

Array, DIMENSION (lld_c, LOCq(jc+n-1)).

This array contains the local pieces of the distributed matrix sub(C).

ic, jc

(global) INTEGER. The row and column indices in the distributed matrix C indicating the first row and the first column of the submatrix sub(C), respectively.

descc

(global and local) INTEGER array of dimension 8. The array descriptor of the distributed matrix C.

Output Parameters

c

Overwritten by the updated submatrix.