Tagged determinism

2 pieces

• October 9, 2026 · 10 min read

  Temperature Zero Is Not Deterministic

  Event sourcing assumes you can replay the source and get the same derived state. A model call in the derivation breaks that assumption, because the lowest temperature setting reduces variation without eliminating it, and providers document this. A model-derived layer cannot be regenerated by replay, so the output and the model version have to be stored as part of the record.

• October 7, 2026 · 8 min read

  Your Decimal Engine Is Still Eating Floats: Determinism Is Decided at the Parser Boundary

  Switching a calculation engine to decimal arithmetic fixes nothing if the numbers arrive as floats. A spreadsheet stores numeric cells as IEEE-754 doubles, the usual dataframe library infers a float type on read, and constructing a decimal from a float inherits the float's error exactly. The engine then computes precisely on a value that was already wrong, and nothing in the stack will tell you.