# Calculational Tools¶

 partial_trace(rho, keep, dims[, optimize]) Calculate the partial trace. outer_product(bra1, bra2) Given two possibly complex row vectors bra1 and bra2 construct the outer product. inner_product(bra1, bra2) Given two possibly complex row vectors bra1 and bra2 construct the inner product. sqrtm_psd(matrix, check_finite) Calculates the square root of a matrix that is positive semidefinite.