Report zero as not normal, and nothing as subnormal [patch] - #129
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IsNormal returned true for every value, so IsNormal(Zero) was true where int, decimal and BigInteger all report false. Generic math that guards a division or a logarithm with IsNormal let PreciseNumber zero through. IsNormal now returns false for zero only. IsSubnormal was written as !IsNormal, which would have flipped it to true for zero; it now returns false for every value, as BigInteger and decimal do, since the exponent carries the magnitude and no value loses digits near zero. Fixes #122 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01LasidbyRZfyxgW8Z9wQu9M
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This was referenced Sep 28, 2026
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Fixes #122
What changed
IsNormalreturnedtruefor every value, soIsNormal(Zero)wastrue.int,decimalandBigIntegerall reportfalsefor zero. It now returns!value.Significand.IsZero.IsSubnormalwas written as!IsNormal(value). WithIsNormalfixed, that would have madeIsSubnormal(Zero)true. It now returnsfalsefor every value, asBigIntegeranddecimaldo.This changes behavior callers can observe: generic math that uses
IsNormalas a "safe to divide or log" guard now rejectsPreciseNumberzero, the same way it rejects zero for the built-in types.Tests
TestZeroIsNotNormalcoversZeroanddefault. It fails onmain.TestNonZeroIntegerIsNormalandTestNonZeroFractionIsNormalcover positive, negative, very small and very large values.TestNothingIsSubnormalcovers zero and non-zero values. It guards againstIsSubnormalgoing back to!IsNormal.TestZeroIsNotNormalfails. With the fix, the full suite passes:dotnet test PreciseNumber.Test, 422/422.🤖 Generated with Claude Code
https://claude.ai/code/session_01LasidbyRZfyxgW8Z9wQu9M
Generated by Claude Code