PickOne experiments

PickOne.circom

pragma circom 2.1.4;

include "circomlib/multiplexer.circom";
include "circomlib/comparators.circom";

// Pick in[sel]
template PickOne(N) {
    signal input in[N];
    signal input sel;
    signal output out;

    component mux = Multiplexer(1, N);
    for (var i = 0; i < N; i++) { mux.inp[i][0] <== in[i]; }
    mux.sel <== sel;
    out <== mux.out[0];
}

template PickOne2(N) {
    signal input in[N];
    signal input sel;
    signal output out;

    component eqs[N];
    signal sums[N];

    eqs[0] = IsEqual();
    eqs[0].in[0] <== 0;
    eqs[0].in[1] <== sel;
    sums[0] <== eqs[0].out * in[0];

    for (var i = 1; i < N; i++) {
        eqs[i] = IsEqual();
        eqs[i].in[0] <== i;
        eqs[i].in[1] <== sel;        
        sums[i] <== eqs[i].out * in[i] + sums[i - 1];
    }
    out <== sums[N - 1];    
}

template Mul() {
    signal input a;
    signal input b;
    signal output out;
    out <== a * b;
}
template PickOne3(N) {
    signal input in[N];
    signal input sel;
    signal output out;

    var sum = 0;
    signal picked[N];
    for (var i = 0; i < N; i++) {
        picked[i] <== Mul()(IsEqual()([i, sel]), in[i]);
        sum += picked[i];
    }
    out <== sum;
}

template PickOne4(N) {
    signal input in[N];
    signal input sel;
    signal output out;

    signal oneAtSel[N];
    var oneCount = 0;
    for (var i = 0; i < N; i++) {
        oneAtSel[i] <-- (i == sel) ? 1 : 0;    // 1 at sel, otherwise 0
        oneAtSel[i] * (oneAtSel[i] - 1) === 0; // only 0 or 1
        oneCount += oneAtSel[i];
    }
    oneCount === 1;
    
    var sum = 0;    
    signal picked[N];
    for (var i = 0; i < N; i++) {
        picked[i] <== oneAtSel[i] * in[i];
        sum += picked[i];
    }
    out <== sum;
}


//component main = PickOne(10);
//component main = PickOne2(10);
//component main = PickOne3(10);
component main = PickOne4(10);

/* INPUT = {
    "in": [ 0, 11, 22, 33, 44, 55, 66, 77, 88, 99 ],
    "sel": 5
} */

zkrepl output for PickOne (Multiplexer)

STDOUT: 
template instances: 4
non-linear constraints: 20
linear constraints: 0
public inputs: 0
public outputs: 1
private inputs: 11
private outputs: 0
wires: 31
labels: 68
Written successfully: ./main.r1cs
Written successfully: ./main.sym
Written successfully: ./main_js/main.wasm
Everything went okay, circom safe
Compiled in 4.95s
OUTPUT: 
out = 55
ARTIFACTS: 
Finished in 6.60s
main.wasm (37.55KB)
main.js (9.18KB)
main.wtns (1.07KB)
main.r1cs (3.70KB)
main.sym (1.78KB)

zkrepl output for PickOne2 (no Multiplexer)

STDOUT: 
template instances: 3
non-linear constraints: 30
linear constraints: 0
public inputs: 0
public outputs: 1
private inputs: 11
private outputs: 0
wires: 42
labels: 83
Written successfully: ./main.r1cs
Written successfully: ./main.sym
Written successfully: ./main_js/main.wasm
Everything went okay, circom safe
Compiled in 3.42s
OUTPUT: 
out = 55
ARTIFACTS: 
Finished in 6.35s
main.wasm (36.52KB)
main.js (9.18KB)
main.wtns (1.42KB)
main.r1cs (5.02KB)
main.sym (2.01KB)

zkrepl output for PickOne3 (no Multiplexer)

STDOUT: 
template instances: 4
non-linear constraints: 30
linear constraints: 0
public inputs: 0
public outputs: 1
private inputs: 11
private outputs: 0
wires: 42
labels: 123
Written successfully: ./main.r1cs
Written successfully: ./main.sym
Written successfully: ./main_js/main.wasm
Everything went okay, circom safe
Compiled in 0.84s
OUTPUT: 
out = 55
ARTIFACTS: 
Finished in 1.74s
main.wasm (37.03KB)
main.js (9.18KB)
main.wtns (1.42KB)
main.r1cs (5.02KB)
main.sym (3.90KB)

zkrepl output for PickOne4 (mimicking Multiplexer)

STDOUT: 
template instances: 1
non-linear constraints: 20
linear constraints: 0
public inputs: 0
public outputs: 1
private inputs: 11
private outputs: 0
wires: 30
labels: 33
Written successfully: ./main.r1cs
Written successfully: ./main.sym
Written successfully: ./main_js/main.wasm
Everything went okay, circom safe
Compiled in 3.02s
OUTPUT: 
out = 55
ARTIFACTS: 
Finished in 3.56s
main.wasm (35.11KB)
main.js (9.18KB)
main.wtns (1.04KB)
main.r1cs (3.98KB)
main.sym (0.69KB)