/*
** error: Error formula to compare two
** matrix multiplies.
** norm(C1-C2)/(macheps*norm(A)*norm(B)),
** Ci=float(A*B)
** macheps=2^(-24) in single prec.
** =2^(-53) in double prec.
*/
double
error(double *mat1,double *mat2,int rows,int cols)
{
const double macheps = 1.110223024625157e-16; /* = 2^(-53) */
return l1_norm_diff(mat1,mat2,rows,cols)/
(macheps*l1_norm(mat1,rows,cols)*l1_norm(mat2,rows,cols));
}
vec2d_int mindex(const int& degree) const
{
int j = 0;
int norm = 0;
std::vector<int> temp(i_dim, 0);
vec2d_int mindex_degree;
while(true)
{
norm = l1_norm(temp);
if(norm == degree)
{
mindex_degree.push_back(temp);
}
for(j = i_dim - 1 ; j >= 0 ; --j)
{
if(++temp[j] <= degree)
break;
else
temp[j] = 0;
}
if( j < 0)
break;
}
return mindex_degree;
}
void Utility::l1_normalize(std::vector<float>& v){
float norm = l1_norm(v);
if(norm == 0.f){
std::cerr << "0 norm" << std::endl;
exit(1);
}
std::for_each(v.begin(), v.end(), [&](float& v){v /= norm;});
}
unsigned long long int min_lattice_vector(long long int * a, long long int * b)
{
unsigned long long int a_norm, b_norm, temp, a_minus_b, a_plus_b;
long long int k = 0;
long long int * t;
a_norm = l1_norm(a);
b_norm = l1_norm(b);
//ensure a has greater norm
if (a_norm < b_norm) {
SWAP(a_norm,b_norm,temp)
SWAP(a,b,t)
}
a_minus_b = lin_comb_mag(a,b,1,-1); // = |a-b|
a_plus_b = lin_comb_mag(a,b,1,1); // = |a+b|
if (a_minus_b < b_norm) {
lin_comb(b,a,b,1,-1); // b = a - b
SWAP(a_minus_b,b_norm,temp)
}
