Developer Reference for Intel® oneAPI Math Kernel Library for C

ID 766684
Date 12/16/2022
Public

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mkl_jit_get_?gemm_ptr

Return the GEMM kernel associated with a jitter previously created with mkl_jit_create_?gemm.

Syntax

sgemm_jit_kernel_t mkl_jit_get_sgemm_ptr(const void* jitter);

dgemm_jit_kernel_t mkl_jit_get_dgemm_ptr(const void* jitter);

cgemm_jit_kernel_t mkl_jit_get_cgemm_ptr(const void* jitter);

zgemm_jit_kernel_t mkl_jit_get_zgemm_ptr(const void* jitter);

Include Files
  • mkl.h
Description

The mkl_jit_get_?gemm_ptr functions belong to a set of related routines that enable use of just-in-time code generation.

The mkl_jit_get_?gemm_ptr functions take as input a jitter previously created with mkl_jit_create_?gemm, and return the GEMM kernel associated with that jitter. The returned GEMM kernel computes a scalar-matrix-matrix product and adds the result to a scalar-matrix product, with general matrices. The operation is defined as follows:

C := alpha*op(A)*op(B) + beta*C

Where:

  • op(X) is one of op(X) = X or op(X) = XT or op(X) = XH
  • alpha and beta are scalars
  • A, B, and C are matrices
  • op(A) is an m-by-k matrix
  • op(B) is a k-by-n matrix
  • C is an m-by-n matrix
NOTE:

Generating a new kernel with mkl_jit_create_?gemm involves moderate runtime overhead. To benefit from JIT code generation, use this feature when you need to call the generated kernel many times (for example, several hundred calls).

Input Parameter

jitter

Handle to the code generator.

Return Values

func

  • sgemm_jit_kernel_t – A function pointer type expecting four inputs of type void*, float*, float*, and float*

    typedef void (*sgemm_jit_kernel_t)(void*,float*,float*,float*);
  • dgemm_jit_kernel_t – A function pointer type expecting four inputs of type void*, double*, double*, and double*

    typedef void(*dgemm_jit_kernel_t)(void*,double*,double*,double*);
  • cgemm_jit_kernel_t – A function pointer type expecting four inputs of type void*, MKL_Complex8*, MKL_Complex8*, and MKL_Complex8*

    typedef void(*cgemm_jit_kernel_t)(void*,MKL_Complex8*,MKL_Complex8*,MKL_Complex8*);
  • zgemm_jit_kernel_t – A function pointer type expecting four inputs of type void*, MKL_Complex16*, MKL_Complex16*, and MKL_Complex16*

    typedef void(*zgemm_jit_kernel_t)(void*,MKL_Complex16*,MKL_Complex16*,MKL_Complex16*);

If the jitter input is not NULL, returns a function pointer to a GEMM kernel. The GEMM kernel is called with four parameters: the jitter and the three matrices a, b, and c. Otherwise, returns NULL.

If layout, transa, transb, m, n, k, lda, ldb, and ldc are the parameters used during the creation of the input jitter, then:

a

  layout = MKL_COL_MAJOR layout = MKL_ROW_MAJOR

transa = MKL_NOTRANS

Array of size lda*k

Before calling the returned function pointer, the leading m-by-k part of the array a must contain the matrix A.

Array of size lda*m

Before calling the returned function pointer, the leading k-by-m part of the array a must contain the matrix A.

transa = MKL_TRANS or transa = MKL_CONJTRANS

Array of size lda*m

Before calling the returned function pointer, the leading k-by-m part of the array a must contain the matrix A.

Array of size lda*k

Before calling the returned function pointer, the leading m-by-k part of the array a must contain the matrix A.

b

  layout = MKL_COL_MAJOR layout = MKL_ROW_MAJOR

transb = MKL_NOTRANS

Array of size ldb*n

Before calling the returned function pointer, the leading k-by-n part of the array b must contain the matrix B.

Array of size ldb*k

Before calling the returned function pointer, the leading n-by-k part of the array b must contain the matrix B.

transb = MKL_TRANS or transb = MKL_CONJTRANS

Array of size ldb*k

Before calling the returned function pointer, the leading n-by-k part of the array b must contain the matrix B.

Array of size ldb*n

Before calling the returned function pointer, the leading k-by-n part of the array b must contain the matrix B.

c

layout = MKL_COL_MAJOR layout = MKL_ROW_MAJOR

Array of size ldc*n

Before calling the returned function pointer, the leading m-by-n part of the array c must contain the matrix C.

Array of size ldc*m

Before calling the returned function pointer, the leading n-by-m part of the array c must contain the matrix C.