p?tradd

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 4/28/2026

Version

Public

p?tradd

Performs sum operation for two distributed triangular matrices.

Syntax

call pstradd ( uplo , trans , m , n , alpha , a , ia , ja , desca , beta , c , ic , jc , descc )

call pdtradd ( uplo , trans , m , n , alpha , a , ia , ja , desca , beta , c , ic , jc , descc )

call pctradd ( uplo , trans , m , n , alpha , a , ia , ja , desca , beta , c , ic , jc , descc )

call pztradd ( uplo , trans , m , n , alpha , a , ia , ja , desca , beta , c , ic , jc , descc )

Include Files

mkl_pblas.h

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, size (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 9. 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, size (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 9. The array descriptor of the distributed matrix C .

Output Parameters

c: Overwritten by the updated submatrix.

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

p?tradd

Syntax

Include Files

Description

Input Parameters

Output Parameters