6.1.6 vsip_dgemp_p - General Matrix Product

typedef enum _vsip_mat_op { 
  VSIP_MAT_NTRANS = 0, // op(A) = A 
  VSIP_MAT_TRANS  = 1, // op(A) = A^T 
  VSIP_MAT_HERM   = 2, // op(A) = A^H (complex only) 
  VSIP_MAT_CONJ   = 3  // op(X) = A^* (complex only) 
} vsip_mat_op; 
 
void vsip_gemp_f(vsip_scalar_f alpha, const vsip_mview_f *a, vsip_mat_op OpA, const vsip_mview_f *b, vsip_mat_op OpB, vsip_scalar_f beta, const vsip_mview_f *r); 
void vsip_cgemp_f(vsip_cscalar_f alpha, const vsip_cmview_f *a, vsip_mat_op OpA, const vsip_cmview_f *b, vsip_mat_op OpB, vsip_cscalar_f beta, const vsip_cmview_f *r);

Description

This function performs a generalized matrix-matrix operation of the form:

where can be , , or .

Parameters

• vsip_dscalar_f alpha: Scalar multiplier for the matrix product.

• const vsip_dmview_p* a: First input matrix.

• vsip_mat_op OpA: Operation to perform on matrix A:

  • VSIP_MAT_NTRANS: Use as is

  • VSIP_MAT_TRANS: Use the transpose of,

  • VSIP_MAT_HERM: Use the conjugate transpose of

  • VSIP_MAT_CONJ: Use the conjugate of

• const vsip_dmview_p* b: Second input matrix.

• vsip_mat_op OpB: Operation to perform on matrix B.

  • VSIP_MAT_NTRANS: Use as is

  • VSIP_MAT_TRANS: Use the transpose of,

  • VSIP_MAT_HERM: Use the conjugate transpose of

  • VSIP_MAT_CONJ: Use the conjugate of

• vsip_dscalar_p beta: Scalar multiplier for matrix .

• const vsip_dmview_p* r: Input/output matrix that contains the initial values and will store the result.

Example

vsip_mview_f *A, *B, *R; 
vsip_length m = 3, n = 2, p = 4; 
 
// Create matrices 
A = vsip_mcreate_f(m, n, VSIP_ROW, VSIP_MEM_NONE); 
B = vsip_mcreate_f(n, p, VSIP_ROW, VSIP_MEM_NONE); 
R = vsip_mcreate_f(m, p, VSIP_ROW, VSIP_MEM_NONE); 
 
// Initialize matrices with some values 
 
// Basic matrix multiplication: R = A * B 
vsip_gemp_f(1.0f, A, VSIP_MAT_NTRANS, B, VSIP_MAT_NTRANS, 0.0f, R); 
 
// Matrix multiplication with scaling: R = 2.0*A*B + R 
vsip_gemp_f(2.0f, A, VSIP_MAT_NTRANS, B, VSIP_MAT_NTRANS, 1.0f, R); 
 
// Transpose operations: R = A^T * B 
vsip_gemp_f(1.0f, A, VSIP_MAT_TRANS, B, VSIP_MAT_NTRANS, 0.0f, R); 
 
// Both transposed: R = A^T * B^T 
vsip_gemp_f(1.0f, A, VSIP_MAT_TRANS, B, VSIP_MAT_TRANS, 0.0f, R); 
 
// Clean up 
vsip_malldestroy_f(A); 
vsip_malldestroy_f(B); 
vsip_malldestroy_f(R);

Notes

• The dimensions of the matrices must be compatible with the operation:

  • If OpA = VSIP_MAT_NTRANS, rows of must match rows of .

  • If OpA = VSIP_MAT_TRANS or VSIP_MAT_HERM, columns of must match rows of .

• The result matrix must have dimensions compatible with the operation.

• The operation is not commutative: in general.

• Setting results in being overwritten with the matrix product.

• Setting results in the matrix product being added to .