Function sequant::mbpt::density_fit

• Defined in File df.cpp

Function Documentation

ExprPtr sequant::mbpt::density_fit(ExprPtr const &expr, IndexSpace aux_space, std::wstring_view tensor_label, std::wstring_view factor_label)

Converts the 4-center (2-electron integral) tensors into a (antisymmetrized) product of two rank-3 tensors.

Parameters:

• expr – The expression to be density-fit.

• aux_space – The index space representing the auxiliary indices introduced through the decomposition.

• tensor_label – The label off the tensor that shall be decomposed

• factor_label – The label of the rank-3 tensors used in the decomposition.

Returns:

The density-fitted expression (potentially unchanged, if the target tensor was not contained in the given expression)