mpqc.Chemistry.Basis.Integral

Modules
	mpqc.Chemistry.Basis.Integral.Range
	mpqc.Chemistry.Basis.Integral.TiledArray

Classes
struct	sc::OneBodyIntEvalType< NumCenters >
	returns the type of the evaluator for evaluating this set of two-body integrals More...
struct	sc::OneBodyIntEvalType< 2 >
struct	sc::OneBodyIntEvalType< 1 >
struct	sc::TwoBodyIntEvalType< NumCenters >
	returns the type of the evaluator for evaluating this set of two-body integrals More...
struct	sc::TwoBodyIntEvalType< 4 >
struct	sc::TwoBodyIntEvalType< 3 >
struct	sc::TwoBodyIntEvalType< 2 >
class	sc::Integral
	The Integral abstract class acts as a factory to provide objects that compute one and two electron integrals. More...

Detailed Description

Classes/functions related to integrals over atomic basis function.

Synopsis:

// get the default Integral factory. MPQC supports several factories that
// may not be interoperable with each other, to be safe use the same one throughout
Ref<Integral> integral_factory = Integral::get_default_integral();
 
// need to compute overlap integrals between 2 basis sets?
integral_factory->set_basis(bs1, bs2);
Ref<OneBodyInt> overlap_12 = integral_factory->overlap();
 
// loop over shell combinations, call overlap_12->compute_shell()
const double* ints_buffer = overlap_12->buffer();
for(int s1=0; s1<bs1->nshell(); ++s1) {
  for(int s2=0; s2<bs2->nshell(); ++s2) {
    // compute shell block
    overlap_12->compute_shell(s1, s2);
 
    // read integrals from ints_buffer
    for(int f1=0, f12=0; f1<bs1->shell(s1).nfunction(); ++f1) {
      for(int f2=0; f2<bs2->shell(s2).nfunction(); ++f2, ++f12) {
        const double v = ints_buffer[f12];
        // integral in v corresponds to these basis functions:
        // bra index = f1 + bs1->shell_to_function(s1)
        // ket index = f2 + bs2->shell_to_function(s2)
        // use v here
      }
    }
 
  }
}

In this example the computed integrals are extracted one-by-one. Often you want to copy the entire shell block of integrals to another array. This can be done using new range-style access described in mpqc.Chemistry.Basis.Integral.Range.