filifa
/
mcalc
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

add special case

This commit is contained in:
filifa 2025-12-11 23:49:34 -05:00
parent f38c0f5063
commit aa1399a574
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
modules/math.js
View File

@ -163,8 +163,6 @@ function modsqrt(n, modulus) {
throw new Error("modulus must be prime to compute square root"); throw new Error("modulus must be prime to compute square root");
} }
// TODO: add special case for modulus = 3 (mod 4)
n %= modulus; n %= modulus;
if (n < 0n) { if (n < 0n) {
n += modulus; n += modulus;
@ -176,6 +174,8 @@ function modsqrt(n, modulus) {
throw new Error("radicand is not a quadratic residue of the modulus"); throw new Error("radicand is not a quadratic residue of the modulus");
} else if (modulus === 2n) { } else if (modulus === 2n) {
return n % 2n; return n % 2n;
} else if (modulus % 4n === 3n) {
return modpow(n, (modulus+1n)/4n, modulus);
} }
return tonelliShanks(n, modulus); return tonelliShanks(n, modulus);