Approximate mode

This guide teaches how to improve the execution time of Concrete circuits by using approximate mode for rounding.

You can enable approximate mode to gain even more performance when using rounding by sacrificing some more exactness:

import numpy as np
from concrete import fhe

inputset = fhe.inputset(fhe.uint10)
for lsbs_to_remove in range(0, 10):
    def f(x):
        return fhe.round_bit_pattern(x, lsbs_to_remove, exactness=fhe.Exactness.APPROXIMATE) // 2

    compiler = fhe.Compiler(f, {"x": "encrypted"})
    circuit = compiler.compile(inputset)

    print(f"{lsbs_to_remove=} -> {int(circuit.complexity):>13_} complexity")

prints:

lsbs_to_remove=0 -> 9_134_406_574 complexity
lsbs_to_remove=1 -> 5_548_275_712 complexity
lsbs_to_remove=2 -> 2_430_793_927 complexity
lsbs_to_remove=3 -> 1_058_638_119 complexity
lsbs_to_remove=4 ->   409_952_712 complexity
lsbs_to_remove=5 ->   172_138_947 complexity
lsbs_to_remove=6 ->    99_198_195 complexity
lsbs_to_remove=7 ->    71_644_380 complexity
lsbs_to_remove=8 ->    55_860_516 complexity
lsbs_to_remove=9 ->    50_978_148 complexity