#scientific computing
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From script to sentence: a traceable Brewster-angle calculation
A tiny Fresnel calculation shows how this site now carries computed values from versioned inputs into prose without mistaking traceability for correctness.
Two runs, two answers: floating-point sums aren't associative
Run the same simulation on four cores and eight and the total energy disagrees in the twelfth digit. That is not a bug in your code — it is floating-point addition refusing to be associative, and the fix is not to make the hardware lie but to know your noise floor.