Browse Source

Removed extraneous range check

main
Uma Roy 2 years ago
parent
commit
8b96b0fd87
1 changed files with 8 additions and 12 deletions
  1. +8
    -12
      goldilocks/base.go

+ 8
- 12
goldilocks/base.go

@ -317,36 +317,32 @@ func (p *Chip) RangeCheck(x Variable) {
// in big endian binary. This function will first verify that x is at most 64 bits wide. Then it
// checks that if the bits[0:31] (in big-endian) are all 1, then bits[32:64] are all zero.
// Use the range checker component to range-check the variable.
rangeChecker := rangecheck.New(p.api)
rangeChecker.Check(x.Limb, 64)
result, err := p.api.Compiler().NewHint(SplitLimbsHint, 2, x.Limb)
if err != nil {
panic(err)
}
// We check that this is a valid decomposition of the Goldilock's element and range-check each limb.
mostSigBits := result[0]
leastSigBits := result[1]
mostSigLimb := result[0]
leastSigLimb := result[1]
p.api.AssertIsEqual(
p.api.Add(
p.api.Mul(mostSigBits, uint64(math.Pow(2, 32))),
leastSigBits,
p.api.Mul(mostSigLimb, uint64(math.Pow(2, 32))),
leastSigLimb,
),
x.Limb,
)
rangeChecker.Check(mostSigBits, 32)
rangeChecker.Check(leastSigBits, 32)
p.rangeChecker.Check(mostSigLimb, 32)
p.rangeChecker.Check(leastSigLimb, 32)
// If the most significant bits are all 1, then we need to check that the least significant bits are all zero
// in order for element to be less than the Goldilock's modulus.
// Otherwise, we don't need to do any checks, since we already know that the element is less than the Goldilocks modulus.
shouldCheck := p.api.IsZero(p.api.Sub(mostSigBits, uint64(math.Pow(2, 32))-1))
shouldCheck := p.api.IsZero(p.api.Sub(mostSigLimb, uint64(math.Pow(2, 32))-1))
p.api.AssertIsEqual(
p.api.Select(
shouldCheck,
leastSigBits,
leastSigLimb,
frontend.Variable(0),
),
frontend.Variable(0),

Loading…
Cancel
Save