mtl-aas/stl/robustness.py
2017-02-28 13:35:01 -08:00

70 lines
1.6 KiB
Python

# TODO: technically incorrect on 0 robustness since conflates < and >
from functools import singledispatch
from operator import sub, add
import numpy as np
from lenses import lens
import stl.ast
oo = float('inf')
@singledispatch
def pointwise_robustness(stl):
raise NotImplementedError
@pointwise_robustness.register(stl.Or)
def _(stl):
return lambda x, t: max(pointwise_robustness(arg)(x, t) for arg in stl.args)
@pointwise_robustness.register(stl.And)
def _(stl):
return lambda x, t: min(pointwise_robustness(arg)(x, t) for arg in stl.args)
@pointwise_robustness.register(stl.F)
def _(stl):
lo, hi = stl.interval
return lambda x, t: max((pointwise_robustness(stl.arg)(x, t + t2)
for t2 in x[lo:hi].index), default=-oo)
@pointwise_robustness.register(stl.G)
def _(stl):
lo, hi = stl.interval
return lambda x, t: min((pointwise_robustness(stl.arg)(x, t + t2)
for t2 in x[lo:hi].index), default=oo)
@pointwise_robustness.register(stl.Neg)
def _(stl):
return lambda x, t: -pointwise_robustness(stl.arg)(x, t)
op_lookup = {
">": sub,
">=": sub,
"<": lambda x, y: sub(y, x),
"<=": lambda x, y: sub(y, x),
"=": lambda a, b: -abs(a - b),
}
@pointwise_robustness.register(stl.LinEq)
def _(stl):
op = op_lookup[stl.op]
return lambda x, t: op(eval_terms(stl, x, t), stl.const)
def eval_terms(lineq, x, t):
psi = lens(lineq).terms.each_().modify(eval_term(x, t))
return sum(psi.terms)
def eval_term(x, t):
# TODO(lift interpolation much higher)
return lambda term: term.coeff*np.interp(t, x.index, x[term.id.name])