some refactoring of __init__()

rotagaporp/propagators.py

@@ -269,6 +269,8 @@ class SymmetricPolynomialPropagator(PolynomialPropagator):
             self.numeric = self.syst.numeric
 
         validate_numeric(self.fpprec, self.numeric)
+        if self.fpprec == 'fixed':
+            self.prec = np.finfo(float).precision
 
         tool = self.numeric['tool']
         assert tool in ['subs', 'lambdify', 'theano']
@@ -282,9 +284,10 @@ class SymmetricPolynomialPropagator(PolynomialPropagator):
         if tool == 'theano':
             self.linalg = 'numpy'
 
-        if self.fpprec == 'fixed':
-            self.prec = np.finfo(float).precision
+        self.set_util_funcs()
 
+    def set_util_funcs(self):
+        """ utility functions depending on numeric backend and type of q """
         if self.linalg == 'sympy':
             self.matrix = sp.Matrix
             self.matmul = lambda x, y: x*y
@@ -302,12 +305,6 @@ class SymmetricPolynomialPropagator(PolynomialPropagator):
             self.normf = np.linalg.norm
 
         if isinstance(self.q, Iterable):
-            assert isinstance(self.p, Iterable)
-            assert isinstance(self.syst.q, Iterable)
-            assert isinstance(self.syst.p, Iterable)
-            assert len(self.q) == len(self.p)
-            assert len(self.q) == len(self.syst.q)
-            assert len(self.syst.q) == len(self.syst.p)
             self.concat = lambda a, b: (*a, *b)
             self.split = lambda x: (x[:len(x)//2], x[len(x)//2:])
         else: