Add comments on default comparisons.

AntelopeIO · Nov 29, 2023 · 6818a31 · 6818a31
1 parent ad21d26
commit 6818a31
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Showing 2 changed files with 14 additions and 1 deletion.
diff --git a/include/bls12-381/fp.hpp b/include/bls12-381/fp.hpp
@@ -62,7 +62,11 @@ class fp
     bool isLexicographicallyLargest() const;
     template<size_t N> static fp modPrime(const std::array<uint64_t, N>& k);
 
-    std::strong_ordering operator<=>(const fp& e) const { return cmp(e); }
+    // Those operators are defined to support set and map.
+    // They are mathematically correctly in certain cases.
+    // However, there are still ambiguity there as the fp can be in Montgomery form or not.
+    // Please avoid using those operators.
+    constexpr std::strong_ordering operator<=>(const fp& e) const { return cmp(e); }
 
     static const fp MODULUS;                            // base field modulus: p = 4002409555221667393417789825735904156556882819939007885332058136124031650490837864442687629129015664037894272559787 or 0x1A0111EA397FE69A4B1BA7B6434BACD764774B84F38512BF6730D2A0F6B0F6241EABFFFEB153FFFFB9FEFFFFFFFFAAAB
     static const uint64_t INP;                          // INP = -(p^{-1} mod 2^64) mod 2^64
@@ -124,6 +128,9 @@ class fp2
     bool isQuadraticNonResidue() const;
     bool isLexicographicallyLargest() const;
 
+    // Those operators are defined to support set and map.
+    // They are not mathematically correct.
+    // DO NOT use them to compare fp2.
     auto operator<=>(const fp2&) const = default;
 
     static const fp2 negativeOne2;

diff --git a/include/bls12-381/g.hpp b/include/bls12-381/g.hpp
@@ -61,6 +61,9 @@ class g1
     g1 clearCofactor() const;
     g1 glvEndomorphism() const;
 
+    // Those operators are defined to support set and map.
+    // They are not mathematically correct.
+    // DO NOT use them to compare g1.
     auto operator<=>(const g1&) const = default;
 
     static g1 weightedSum(std::span<const g1> points, std::span<const std::array<uint64_t, 4>> scalars, const std::function<void()>& yield = std::function<void()>());
@@ -121,6 +124,9 @@ class g2
     g2 clearCofactor() const;
     g2 frobeniusMap(int64_t power) const;
 
+    // Those operators are defined to support set and map.
+    // They are not mathematically correct.
+    // DO NOT use them to compare g2.
     auto operator<=>(const g2&) const = default;
 
     static g2 weightedSum(std::span<const g2> points, std::span<const std::array<uint64_t, 4>> scalars, const std::function<void()>& yield = std::function<void()>());