circomlib/circuits/comparators.circom
2018-12-06 17:32:49 +01:00

56 lines
890 B
Plaintext

include "bitify.circom";
include "binsum.circom";
template IsZero() {
signal input in;
signal output out;
signal inv;
inv <-- in!=0 ? 1/in : 0;
out <== -in*inv +1;
in*out === 0;
}
template IsEqual() {
signal input in[2];
signal output out;
component isz = IsZero();
in[1] - in[0] ==> isz.in;
isz.out ==> out;
}
// N is the number of bits the input have.
// The MSF is the sign bit.
template LessThan(n) {
signal input in[2];
signal output out;
component num2Bits0;
component num2Bits1;
component adder;
adder = BinSum(n, 2);
num2Bits0 = Num2Bits(n);
num2Bits1 = Num2BitsNeg(n);
in[0] ==> num2Bits0.in;
in[1] ==> num2Bits1.in;
var i;
for (i=0;i<n;i++) {
num2Bits0.out[i] ==> adder.in[0][i];
num2Bits1.out[i] ==> adder.in[1][i];
}
adder.out[n-1] ==> out;
}