45 lines
1.4 KiB
Python
45 lines
1.4 KiB
Python
from stl.utils import set_params, param_lens
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from stl.robustness import pointwise_robustness
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from lenses import lens
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def binsearch(stleval, *, tol=1e-3, lo, hi, polarity):
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"""Only run search if tightest robustness was positive."""
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# Only check low since hi taken care of by precondition.
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# TODO: allow for different polarities
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rL, rH = stleval(lo), stleval(hi)
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# Early termination via bounds checks
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posL, posH = rL > 0, rH > 0
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if polarity and posL:
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return lo
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elif not polarity and posH:
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return hi
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while hi - lo > tol:
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mid = lo + (hi - lo) / 2
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r = stleval(mid)
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if not polarity: # swap direction
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r *= -1
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if r < 0:
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lo, hi = mid, hi
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else:
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lo, hi = lo, mid
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# Want satisifiable formula
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return hi if polarity else lo
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def lex_param_project(stl, x, *, order, polarity, ranges, tol=1e-3):
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val = {var: (ranges[var][0] if not polarity[var] else ranges[var][1]) for var in order}
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p_lens = param_lens(stl)
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def stleval_fact(var, val):
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l = lens(val)[var]
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return lambda p: pointwise_robustness(set_params(stl, l.set(p)))(x, 0)
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for var in order:
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stleval = stleval_fact(var, val)
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lo, hi = ranges[var]
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param = binsearch(stleval, lo=lo, hi=hi, tol=tol, polarity=polarity[var])
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val[var] = param
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return val
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