`numpy._core.einsumfunc:_find_contraction`

Signature

def _find_contraction ( positions , input_sets , output_set )

Finds the contraction for a given set of input and output sets.

positions : iterable: Integer positions of terms used in the contraction.
input_sets : list: List of sets that represent the lhs side of the einsum subscript
output_set : set: Set that represents the rhs side of the overall einsum subscript

new_result : set: The indices of the resulting contraction
remaining : list: List of sets that have not been contracted, the new set is appended to the end of this list
idx_removed : set: Indices removed from the entire contraction
idx_contraction : set: The indices used in the current contraction

# A simple dot product test case

pos = (0, 1)
isets = [set('ab'), set('bc')]
oset = set('ac')
_find_contraction(pos, isets, oset)

# A more complex case with additional terms in the contraction

pos = (0, 2)
isets = [set('abd'), set('ac'), set('bdc')]
oset = set('ac')
_find_contraction(pos, isets, oset)