p?dot

Developer Reference for Intel® oneAPI Math Kernel Library for C

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ID 766684

Date 4/28/2026

Version

Public

p?dot

Computes the dot product of two distributed real vectors.

Syntax

void psdot ( const MKL_INT*n , float*dot , const float*x , const MKL_INT*ix , const MKL_INT*jx , const MKL_INT*descx , const MKL_INT*incx , const float*y , const MKL_INT*iy , const MKL_INT*jy , const MKL_INT*descy , const MKL_INT*incy );

void pddot ( const MKL_INT*n , double*dot , const double*x , const MKL_INT*ix , const MKL_INT*jx , const MKL_INT*descx , const MKL_INT*incx , const double*y , const MKL_INT*iy , const MKL_INT*jy , const MKL_INT*descy , const MKL_INT*incy );

Include Files

mkl_pblas.h

Description

The ?dot functions compute the dot product dot of two distributed real vectors defined as

dot = sub( x )’*sub( y )

where sub(x) and sub(y) are n -element distributed vectors.

sub(x) denotes X(ix, jx:jx+n-1) if incx=m_x , and X(ix: ix+n-1, jx) if incx= 1 ;

sub(y) denotes Y(iy, jy:jy+n-1) if incy=m_y , and Y(iy: iy+n-1, jy) if incy= 1 .

Input Parameters

n

(global) The length of distributed vectors, n ≥ 0.

x

(local)

DOUBLE PRECISION for pddot Array, size (jx-1)*m_x + ix+(n-1)*abs(incx)) . This array contains the entries of the distributed vector sub(x) .

ix , jx

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

descx

(global and local) array of dimension 9. The array descriptor of the distributed matrix X .

incx

(global) Specifies the increment for the elements of sub(x) . Only two values are supported, namely 1 and m_x . incx must not be zero.

y

(local)

DOUBLE PRECISION for pddot Array, size (jy-1)*m_y + iy+(n-1)*abs(incy)) . This array contains the entries of the distributed vector sub(y) .

iy , jy

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

descy

(global and local) array of dimension 9. The array descriptor of the distributed matrix Y .

incy

(global) Specifies the increment for the elements of sub(y) . Only two values are supported, namely 1 and m_y . incy must not be zero.

Output Parameters

dot

(local)

DOUBLE PRECISION for pddot Dot product of sub(x) and sub(y) only in their scope.

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Developer Reference for Intel® oneAPI Math Kernel Library for C

p?dot

Syntax

Include Files

Description

Input Parameters

Output Parameters