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jacobwilliams / roots-fortran

A modern Fortran library for finding the roots of continuous scalar functions of a single real variable, using derivative-free methods.
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muller failure #12

Closed jacobwilliams closed 2 years ago

jacobwilliams commented 2 years ago

Muller has a failed test case when using quad precision

fpm test --compiler ifort  --flag "-DREAL128"

It claims to have succeeded, but doesn't produce a valid root:

              method fun    n            error                         x                f evals iflag runs/sec
-------------------- --- ---- ---------------- ------------------------- ---------------- ----- ----- --------
              muller   2    1     2.270847E-01    3.2499999995000000E+00     3.192712E+00     5     0  2.6E+03

The actual root is at x=3.0229153472730570E+00.