int blockMatrixMultiply(double* a, double* b, double* out, int n, int m){
const int s = n/m;
const int r = n - s*m;
const int matrix_size = n*n;
const int block_size = m*m;
const int string_size = m*n;
const int small_block_size = r*m;
const int smallest_block_size = r*r;
int i, j, k;
int res = zeroMatrix(out, matrix_size);
if (res!=0){
printf("zeroMatrix failed!\n\t--blockmatrixmultiply\n");
}
double* const temp_block = new double[block_size];
if (r>0){
for (i=0; i<s; i++){
for (j=0; j<s; j++){
for (k=0; k<s; k++){
res = simpleMatrixMultiply(a+i*string_size+k*block_size, b+k*string_size+j*block_size, temp_block, m, m, m);
res = addToMatrix(out+i*string_size+j*block_size, temp_block, block_size);
}
res = simpleMatrixMultiply(a+i*string_size+s*block_size, b+s*string_size+j*small_block_size, temp_block, m, r, m);
res = addToMatrix(out+i*string_size+j*block_size, temp_block, block_size);
}
for (k=0; k<s; k++){
res = simpleMatrixMultiply(a+i*string_size+k*block_size, b+k*string_size+s*block_size, temp_block, m, m, r);
res = addToMatrix(out+i*string_size+s*block_size, temp_block, small_block_size);
}
res = simpleMatrixMultiply(a+i*string_size+s*block_size, b+s*string_size+s*small_block_size, temp_block, m, r, r);
res = addToMatrix(out+i*string_size+s*block_size, temp_block, small_block_size);
}
for (j=0; j<s; j++){
for (k=0; k<s; k++){
res = simpleMatrixMultiply(a+s*string_size+k*small_block_size, b+k*string_size+j*block_size, temp_block, r, m, m);
res = addToMatrix(out+s*string_size+j*small_block_size, temp_block, small_block_size);
}
res = simpleMatrixMultiply(a+s*string_size+s*small_block_size, b+s*string_size+j*small_block_size, temp_block, r, r, m);
res = addToMatrix(out+s*string_size+j*small_block_size, temp_block, small_block_size);
}
for (k=0; k<s; k++){
res = simpleMatrixMultiply(a+s*string_size+k*small_block_size, b+k*string_size+s*block_size, temp_block, r, m, r);
res = addToMatrix(out+s*string_size+s*small_block_size, temp_block, smallest_block_size);
}
res = simpleMatrixMultiply(a+s*string_size+s*small_block_size, b+s*string_size+s*small_block_size, temp_block, r, r, r);
res = addToMatrix(out+s*string_size+s*small_block_size, temp_block, smallest_block_size);
}
else{
for (i=0; i<s; i++){
for (j=0; j<s; j++){
for (k=0; k<s; k++){
res = simpleMatrixMultiply(a+i*string_size+k*block_size, b+k*string_size+j*block_size, temp_block, m, m, m);
res = addToMatrix(out+i*string_size+j*block_size, temp_block, block_size);
}
}
}
}
delete[] temp_block;
return 0;
}
void setMatrix(PETScMatrix& m,
std::initializer_list<double> values)
{
m.setZero();
addToMatrix(m, values);
}
