internal static double SumSquaredDiffs(DoubleArrayVector x, SparseVector y)
{
double sum = 0;
int xlen = x.Length;
int ylen = y.Length;
int i = 0;
int j = 0;
while (i < xlen && j < ylen){
if (i == y.indices[j]){
double d = x.values[i++] - y.values[j++];
sum += d*d;
} else if (i > y.indices[j]){
sum += y.values[j]*y.values[j];
++j;
} else{
sum += x.values[i]*x.values[i];
++i;
}
}
while (i < xlen){
sum += x.values[i]*x.values[i];
++i;
}
while (j < ylen){
sum += y.values[j]*y.values[j];
++j;
}
return sum;
}
internal static double Dot(DoubleArrayVector x, SparseVector y)
{
double sum = 0;
int xlen = x.Length;
int ylen = y.Length;
int i = 0;
int j = 0;
while (i < xlen && j < ylen){
if (i == y.indices[j]){
sum += x.values[i++]*y.values[j++];
} else{
if (i > y.indices[j]){
++j;
} else{
++i;
}
}
}
return sum;
}