Document that GLPK/exact can be inexact #35773
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No, these are just symlinks that eventually lead to |
mkoeppe
reviewed
Jun 14, 2023
| The only access to data is via double-precision floats, however. It | ||
| reconstructs rationals from doubles and also provides results | ||
| as doubles. | ||
| The only access to data is via double-precision floats, which |
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why the extra indent? maybe you want a .. note::?
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A simple mistake, fixed and force-pushed.
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Documentation preview for this PR (built with commit 7b4046c) is ready! 🎉 |
mkoeppe
approved these changes
Jun 15, 2023
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📚 Description
The GLPK/exact linear programming (LP) backend isn't exact because rationals are converted to doubles to be passed to the backend. This means that, despite solving LPs exactly over the rationals, the solver can silently solve a rounded version of your LP. For example, coefficients of 1/3 are handled incorrectly as they are rounded to some 0.3333333ish number that fits in a double-precision float.
This PR simply expands the relevant documentation to explain more carefully that this can lead to problems. Fixes #35727.
The modified files lie in the
src/subdirectory, are changes required to files with the same relative path under such as/build/pkgs/sagemath_environment/...,build/pkgs/sagemath_repl/..., andpkgs/sagemath-repl/...?📝 Checklist
⌛ Dependencies