TSparseMat oprods(const TVec &a, const TVec &b)
// returns outerproduct of a and b: a * trans(b)
{
TSparseMat result;
Int i;
result.SetSize(a.Elts(), b.Elts());
for (i = 0; i < a.Elts(); i++)
if (TSparseVec::IsNonZero(a[i]))
{
result[i] = b;
result[i] *= a[i];
}
else
result[i] = vl_0;
return(result);
}
TVReal dot(const TSparseVec &a, const TVec &b)
{
Assert(a.Elts() == b.Elts(), "(SparseVec::dot) Vec sizes don't match");
TMReal sum = vl_zero;
Int i;
for (i = 0; i < a.NumItems() - 1; i++)
sum += a[i].elt * b[a[i].index];
return(sum);
}
TVec operator * (const TSparseMat &m, const TVec &v)
{
Assert(m.Cols() == v.Elts(), "(SparseMat::*v) matrix and vector sizes don't match");
Int i;
TVec result(m.Rows());
for (i = 0; i < m.Rows(); i++)
result[i] = dot(m[i], v);
return(result);
}
TMReal dot(const TMVec &a, const TVec &b)
{
Assert(a.Elts() == b.Elts(), "(Vec::dot) Vec sizes don't match");
TMReal sum = vl_zero;
Int i;
for (i = 0; i < a.Elts(); i++)
sum += a[i] * b[i];
return(sum);
}
TVec operator * (const TVec &v, const TMat &m) // v * m
{
Assert(v.Elts() == m.Rows(), "(Mat::v*m) vector/matrix sizes don't match");
TMVec temp(m.Cols(), vl_zero); // accumulate in high precision
TVec result(m.Cols()); // return low precision.
Int i;
for (i = 0; i < m.Rows(); i++)
temp += m[i] * v[i];
for (i = 0; i < temp.Elts(); i++)
result[i] = temp[i];
return(result);
}
TVec operator * (const TVec &v, const TSparseMat &m) // v * m
{
Assert(v.Elts() == m.Rows(), "(Mat::v*m) vector/matrix sizes don't match");
TVec result(m.Cols());
Int i, j;
result = vl_zero;
// v * M = v[0] * m[0] + v[1] * m[1] + ...
for (i = 0; i < m.Rows(); i++)
if (len(v[i]) > 0)
for (j = 0; j < m[i].NumItems() - 1; j++)
result[m[i][j].index] += v[i] * m[i][j].elt;
return(result);
}
