fix bug in robustness calculation + move synth for it's on module

robustness.py

@@ -4,7 +4,6 @@ from operator import sub, add
 from lenses import lens
 
 import stl.ast
-from stl.utils import set_params, param_lens
 
 oo = float('inf')
 
@@ -45,8 +44,8 @@ def _(stl):
 op_lookup = {
     ">": sub,
     ">=": sub,
-    "<": add,
-    "<=": add,
+    "<": lambda x, y: sub(y, x),
+    "<=": lambda x, y: sub(y, x),
     "=": lambda a, b: -abs(a - b),
 }
 
@@ -64,45 +63,3 @@ def eval_terms(lineq, x, t):
 
 def eval_term(x, t):
     return lambda term: term.coeff*x[term.id.name][t]
-
-
-def binsearch(stleval, *, tol=1e-3, lo, hi, polarity):
-    """Only run search if tightest robustness was positive."""
-    # Only check low since hi taken care of by precondition.
-    # TODO: allow for different polarities
-    rL, rH = stleval(lo), stleval(hi)
-    # Early termination via bounds checks
-    posL, posH = rL > 0, rH > 0
-    if polarity and posL:
-        return lo
-    elif not polarity and posH:
-        return hi
-
-    while hi - lo > tol:
-        mid = lo + (hi - lo) / 2
-        r = stleval(mid)
-        if not polarity: # swap direction
-            r *= -1
-        if r < 0:
-            lo, hi = mid, hi
-        else:
-            lo, hi = lo, mid
-    
-    # Want satisifiable formula
-    return hi if polarity else lo
-
-
-def lex_param_project(stl, x, *, order, polarity, ranges, tol=1e-3):
-    val = {var: (ranges[var][0] if not polarity[var] else ranges[var][1]) for var in order}
-    p_lens = param_lens(stl)
-    def stleval_fact(var, val):
-        l = lens(val)[var]
-        return lambda p: pointwise_robustness(set_params(stl, l.set(p)))(x, 0)
-    
-    for var in order:
-        stleval = stleval_fact(var, val)
-        lo, hi = ranges[var]
-        param = binsearch(stleval, lo=lo, hi=hi, tol=tol, polarity=polarity[var])
-        val[var] = param
-
-    return val