"""Is fun7 a method failure or a SCORING failure?

Every method stops on fun7 within 8-22 evaluations and every one is scored unsolved. This
checks the only thing that matters: is f actually zero at the point each method returned?
If it is, the methods found a root and the benchmark's |x - declared_root| <= 1e-6 check is
what fails — 5 of the 45 problems then contribute 200 dead evaluations each to EVERY
method's total, which is a fact about the scoring, not about the methods.

    python -u diag_fun7_root.py
"""

from __future__ import annotations

import inspect
import math

from scipy.optimize._tstutils import _CHANDRUPATLA_TESTS_DICTS

from simroot.baselines import best_of, chandrupatla, chandrupatla_scipy
from simroot.pure import pure_root
from sweep_full import MAXFEV, XTOL

CHA = best_of(chandrupatla, chandrupatla_scipy)


def main():
    for d in _CHANDRUPATLA_TESTS_DICTS:
        if not str(d["ID"]).startswith("fun7"):
            continue
        f, root = d["f"], float(d["root"])
        a, b = (float(v) for v in d["bracket"])
        x_o, n_o, _ok = pure_root(f, a, b, XTOL, MAXFEV, similarity="ratio",
                                  scale="derived3", guard="safe", prestep="slope",
                                  direction="dissimilar")
        x_c, n_c, _okc = CHA(f, a, b, XTOL, MAXFEV)
        print(f"{d['ID']:<8} declared root {root:+.3g}")
        for nm, x, n in (("ours", x_o, n_o), ("chandrupatla", float(x_c), n_c)):
            fx = f(x)
            print(f"   {nm:<13} returned x={x:+.10g} after {n:3d} evals  "
                  f"f(x)={fx:+.3e}  |x-root|={abs(x - root):.3g}  "
                  f"{'f IS ZERO THERE' if fx == 0.0 else 'f is not zero'}")
        # how wide is the flat zero region around the declared root?
        w = 0.0
        for k in range(0, 40):
            t = 10.0 ** (-12 + k * 0.5)
            if f(root + t) == 0.0:
                w = t
            else:
                break
        print(f"   f is identically zero at least up to root + {w:.3g}")
    src = inspect.getsource(_CHANDRUPATLA_TESTS_DICTS[0]["f"]) if False else None
    if src:
        print(src)


if __name__ == "__main__":
    main()