# Summary The `ivas_dirac_dec_binaural_formulate_input_covariance_matrices_fx` function makes extensive use of float-like operations (e.g. `BASOP_Util_Add_Mant32Exp`) which are computationally expensive and not really necessary. Those operations can be swapped with cheaper 64-bit low-level operations. # Complexity analysis Current implementation: cumulative max 6.580 Optimised implementation: cumulative max 2.570 # Accuracy analysis The optimised implementation does not normalise/truncate 64-bits integers, tries to be as precise as possible when performing summations and multiplications with 64-bits integers. Unfortunately, it does not operate on normalised values (as the current implementation does), and that makes this optimised implementation slightly less accurate than the current one when processing "tiny" input values.