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Precision: a machine number anywhere gives MachinePrecision, as in WMA - #2059
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Part of MATH-227 (an older difference noted in #2050). Precision[{{a, 2, 3.2`}, {2.1``3, 3.2``5, "a"}}] was 3.32222, the lowest precision of the numbers; WMA gives MachinePrecision, as it does whenever the expression holds a machine number. A flat list only got that right because the lowest value happened to be the machine precision. The check is now on the numbers themselves, so an arbitrary-precision number with 15.9546 digits keeps its value. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
… as in WMA Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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LGTM. Feel free to merge when CI finishes. |
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Part of #2047: the older difference noted in #2050. Independent of the other open PRs: this one is against master.
In WMA,
Precisionof an expression that holds a machine number isMachinePrecision, whatever the other numbers are:Precision[{{a, 2, 3.2`}, {2.13, 3.25, "a"}}]3.32222MachinePrecisionMachinePrecisionPrecision[{1.5`10, 1.5}]10.MachinePrecisionMachinePrecisionPrecision[f[1.5`3, x, 2.]]3.MachinePrecisionMachinePrecisionPrecision[{1.5`20, 1.5}]MachinePrecisionMachinePrecisionMachinePrecisionA flat list such as
{1.520, 1.5}was right only because its lowest precision happened to equal the machine precision. The check now looks for a machine number in the expression (has_machine_number), not at the value. So an arbitrary-precision number with 15.9546 digits, such asN[Pi, $MachinePrecision]`, keeps its value, as in WMA.Tests
In
test_precision, the two lists from the table expected3.andPrecision[2.13]. They now expect `MachinePrecision`. Three new cases. The `Precision` doctest `Precision[{{1, 1.`},{1.`5, 1.`10}}]` expected `5.`; WMA gives `MachinePrecision`. It now shows both: with1.20`` in place of ``1.``` it gives5.`. Full run on kimmy: doctests all pass (4605). The pytest failures are the ones that depend on the order the tests run in; the failing files that touch numbers pass on their own.🤖 Generated with Claude Code