T SparseVectorCompressed<T>::distanceSquared(const MyT& rhs) const
{
Assert(isValid() && rhs.isValid());
Assert(n == rhs.n);
int ak=0,bk=0;
int ai,bi;
T res = 0;
while(ak<num_entries || bk<rhs.num_entries) {
ai = (ak<num_entries? indices[ak] : n);
bi = (bk<rhs.num_entries? rhs.indices[bk] : n);
if(ai < bi) {
res += Sqr(vals[ak]);
ak++;
}
else if(bi < ai) {
res += Sqr(rhs.vals[bk]);
bk++;
}
else {
res += Sqr(vals[ak]-rhs.vals[bk]);
ak++; bk++;
}
}
return res;
}
void SparseVectorCompressed<T>::sub(const MyT& a, const MyT& b)
{
Assert(this != &a && this != &b);
Assert(a.n == b.n);
Assert(a.isValid() && b.isValid());
int ak=0,bk=0;
int ai,bi;
int nnz=0;
while(ak<a.num_entries || bk<b.num_entries) {
ai = (ak<a.num_entries? a.indices[ak] : n);
bi = (bk<b.num_entries? b.indices[bk] : n);
if(ai < bi) ak++;
else if (bi < ai) bk++;
else { ak++; bk++; }
nnz++;
}
resize(a.n,nnz);
nnz=0; ak=0;bk=0;
while(ak<a.num_entries || bk<b.num_entries) {
ai = (ak<a.num_entries? a.indices[ak] : n);
bi = (bk<b.num_entries? b.indices[bk] : n);
if(ai < bi) {
indices[nnz] = ai;
vals[nnz] = a.vals[ak];
ak++;
}
else if(bi < ai) {
indices[nnz] = bi;
vals[nnz] = b.vals[bk];
bk++;
}
else {
indices[nnz] = ai;
vals[nnz] = a.vals[ak]-b.vals[bk];
ak++; bk++;
}
nnz++;
}
}
