cblas_?gemm

Developer Reference for Intel® oneAPI Math Kernel Library for C

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ID 766684

Date 12/16/2022

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cblas_?gemm_batch

Computes scalar-matrix-matrix products and adds the results to scalar matrix products for groups of general matrices.

Syntax

void cblas_sgemm_batch (const CBLAS_LAYOUT Layout, const CBLAS_TRANSPOSE* transa_array, const CBLAS_TRANSPOSE* transb_array, const MKL_INT* m_array, const MKL_INT* n_array, const MKL_INT* k_array, const float* alpha_array, const float **a_array, const MKL_INT* lda_array, const float **b_array, const MKL_INT* ldb_array, const float* beta_array, float **c_array, const MKL_INT* ldc_array, const MKL_INT group_count, const MKL_INT* group_size);

void cblas_dgemm_batch (const CBLAS_LAYOUT Layout, const CBLAS_TRANSPOSE* transa_array, const CBLAS_TRANSPOSE* transb_array, const MKL_INT* m_array, const MKL_INT* n_array, const MKL_INT* k_array, const double* alpha_array, const double **a_array, const MKL_INT* lda_array, const double **b_array, const MKL_INT* ldb_array, const double* beta_array, double **c_array, const MKL_INT* ldc_array, const MKL_INT group_count, const MKL_INT* group_size);

void cblas_cgemm_batch (const CBLAS_LAYOUT Layout, const CBLAS_TRANSPOSE* transa_array, const CBLAS_TRANSPOSE* transb_array, const MKL_INT* m_array, const MKL_INT* n_array, const MKL_INT* k_array, const void *alpha_array, const void **a_array, const MKL_INT* lda_array, const void **b_array, const MKL_INT* ldb_array, const void *beta_array, void **c_array, const MKL_INT* ldc_array, const MKL_INT group_count, const MKL_INT* group_size);

void cblas_zgemm_batch (const CBLAS_LAYOUT Layout, const CBLAS_TRANSPOSE* transa_array, const CBLAS_TRANSPOSE* transb_array, const MKL_INT* m_array, const MKL_INT* n_array, const MKL_INT* k_array, const void *alpha_array, const void **a_array, const MKL_INT* lda_array, const void **b_array, const MKL_INT* ldb_array, const void *beta_array, void **c_array, const MKL_INT* ldc_array, const MKL_INT group_count, const MKL_INT* group_size);

Include Files

mkl.h

Description

The ?gemm_batch routines perform a series of matrix-matrix operations with general matrices. They are similar to the ?gemm routine counterparts, but the ?gemm_batch routines perform matrix-matrix operations with groups of matrices, processing a number of groups at once. The groups contain matrices with the same parameters.

The operation is defined as

idx = 0
for i = 0..group_count - 1
     alpha and beta in alpha_array[i] and beta_array[i]
     for j = 0..group_size[i] - 1 
          A, B, and C matrix in a_array[idx], b_array[idx], and c_array[idx]
          C := alpha*op(A)*op(B) + beta*C,
          idx = idx + 1
     end for
 end for

where:

op(X) is one of op(X) = X, or op(X) = X^T, or op(X) = X^H,

alpha and beta are scalar elements of alpha_array and beta_array,

A, B and C are matrices such that for m, n, and k which are elements of m_array, n_array, and k_array:

op(A) is an m-by-k matrix,

op(B) is a k-by-n matrix,

C is an m-by-n matrix.

A, B, and C represent matrices stored at addresses pointed to by a_array, b_array, and c_array, respectively. The number of entries in a_array, b_array, and c_array is total_batch_count = the sum of all of the group_size entries.

See also gemm for a detailed description of multiplication for general matrices and ?gemm3m_batch, BLAS-like extension routines for similar matrix-matrix operations.

NOTE:

Error checking is not performed for oneMKL Windows* single dynamic libraries for the?gemm_batch routines.

Input Parameters

Layout

Specifies whether two-dimensional array storage is row-major (CblasRowMajor) or column-major (CblasColMajor).

transa_array

Array of size group_count. For the group i, transa_i = transa_array[i] specifies the form of op(A) used in the matrix multiplication:

if transa_i = CblasNoTrans, then op(A) = A;

if transa_i = CblasTrans, then op(A) = A^T;

if transa_i = CblasConjTrans, then op(A) = A^H.

transb_array

Array of size group_count. For the group i, transb_i = transb_array[i] specifies the form of op(B_i) used in the matrix multiplication:

if transb_i = CblasNoTrans, then op(B) = B;

if transb_i = CblasTrans, then op(B) = B^T;

if transb_i = CblasConjTrans, then op(B) = B^H.

m_array

Array of size group_count. For the group i, m_i = m_array[i] specifies the number of rows of the matrix op(A) and of the matrix C.

The value of each element of m_array must be at least zero.

n_array

Array of size group_count. For the group i, n_i = n_array[i] specifies the number of columns of the matrix op(B) and the number of columns of the matrix C.

The value of each element of n_array must be at least zero.

k_array

Array of size group_count. For the group i, k_i = k_array[i] specifies the number of columns of the matrix op(A) and the number of rows of the matrix op(B).

The value of each element of k_array must be at least zero.

alpha_array

Array of size group_count. For the group i, alpha_array[i] specifies the scalar alpha_i.

a_array

Array, size total_batch_count, of pointers to arrays used to store A matrices.

lda_array

Array of size group_count. For the group i, lda_i = lda_array[i] specifies the leading dimension of the array storing matrix A as declared in the calling (sub)program.

	transa_i=CblasNoTrans	transa_i=CblasTrans or transa_i=CblasConjTrans
Layout = CblasColMajor	lda_i must be at least `max(1, m_i)`.	lda_i must be at least `max(1, k_i)`
Layout = CblasRowMajor	lda_i must be at least `max(1, k_i)`	lda_i must be at least `max(1, m_i)`.

b_array

Array, size total_batch_count, of pointers to arrays used to store B matrices.

ldb_array

Array of size group_count. For the group i, ldb_i = ldb_array[i] specifies the leading dimension of the array storing matrix B as declared in the calling (sub)program.

	transb_i=CblasNoTrans	transb_i=CblasTrans or transb_i=CblasConjTrans
Layout = CblasColMajor	ldb_i must be at least `max(1, k_i)`.	ldb_i must be at least `max(1, n_i)`.
Layout = CblasRowMajor	ldb_i must be at least `max(1, n_i)`.	ldb_i must be at least `max(1, k_i)`.

beta_array

Array of size group_count. For the group i, beta_array[i] specifies the scalar beta_i.

When beta_i is equal to zero, then C matrices in group i need not be set on input.

c_array

Array, size total_batch_count, of pointers to arrays used to store C matrices.

ldc_array

Array of size group_count. For the group i, ldc_i = ldc_array[i] specifies the leading dimension of all arrays storing matrix C in group i as declared in the calling (sub)program.

When Layout = CblasColMajorldc_i must be at least max(1, m_i).

When Layout = CblasRowMajorldc_i must be at least max(1, n_i).

group_count

Specifies the number of groups. Must be at least 0.

group_size

Array of size group_count. The element group_size[i] specifies the number of matrices in group i. Each element in group_size must be at least 0.

Output Parameters

c_array: Output buffer, overwritten by total_batch_count matrix multiply operations of the form alpha*op(A)*op(B) + beta*C.

Parent topic: BLAS-like Extensions

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cblas_?gemm_batch