'Segmentation fault (core dumped)' error when doing
multiply(G1, -1)
On bn128. Happened with the few other negative numbers I tried. Did not try with other curves, I assume the problem persists because -1 // 2 = -1 and the recursive nature of the multiply function.
How can it be fixed
This fixes it:
def multiply(pt: Point2D[Field], n: int) -> Point2D[Field]:
m = abs(n)
if m == 0:
ret = None
elif m == 1:
ret = pt
elif not m % 2:
ret = multiply(double(pt), m // 2)
else:
ret = add(multiply(double(pt), int(m // 2)), pt)
if n < 0:
ret = neg(ret)
return ret
alternatively this should work as well but might be less efficient:
def multiply(pt: Point2D[Field], n: int) -> Point2D[Field]:
n = n % field_modulus
# rest of the function still the same
pip freeze): argcomplete==1.12.3 attrs==21.4.0 cached-property==1.5.2 certifi==2022.5.18.1 cytoolz==0.11.2 eth-hash==0.3.2 eth-typing==3.0.0 eth-utils==2.0.0 hypothesis==6.46.11 iniconfig==1.1.1 mypy-extensions==0.4.3 numpy==1.22.4 packaging==21.3 pandas==1.4.2 pipx==0.16.4 pluggy==1.0.0 py==1.11.0 py-ecc==6.0.0 pyparsing==3.0.9 pytest==7.1.2 python-dateutil==2.8.2 pytz==2022.1 six==1.16.0 sortedcontainers==2.4.0 tomli==2.0.1 toolz==0.11.2 userpath==1.7.0What is wrong?
'Segmentation fault (core dumped)' error when doing
On bn128. Happened with the few other negative numbers I tried. Did not try with other curves, I assume the problem persists because -1 // 2 = -1 and the recursive nature of the multiply function.
How can it be fixed
This fixes it:
alternatively this should work as well but might be less efficient:
Could write up a quick PR if this indeed works.