void AdaptiveSparseGrid<Scalar,UserVector>::build_diffRule(
CubatureTensorSorted<Scalar> & outRule,
std::vector<int> index,
AdaptiveSparseGridInterface<Scalar,UserVector> & problem_data) {
int numPoints = 0;
int dimension = problem_data.getDimension();
bool isNormalized = problem_data.isNormalized();
std::vector<EIntrepidBurkardt> rule1D; problem_data.getRule(rule1D);
std::vector<EIntrepidGrowth> growth1D; problem_data.getGrowth(growth1D);
for (int i=0; i<dimension; i++) {
// Compute 1D rules
numPoints = growthRule1D(index[i],growth1D[i],rule1D[i]);
CubatureLineSorted<Scalar> diffRule1(rule1D[i],numPoints,isNormalized);
if (numPoints!=1) { // Compute differential rule
numPoints = growthRule1D(index[i]-1,growth1D[i],rule1D[i]);
CubatureLineSorted<Scalar> rule1(rule1D[i],numPoints,isNormalized);
diffRule1.update(-1.0,rule1,1.0);
}
// Build Tensor Rule
outRule = kron_prod<Scalar>(outRule,diffRule1);
}
}
