Handle any exponant, add a try_to_cast_integer in util

ode.pl

@@ -61,6 +61,7 @@
 % Only for separate compilation/linking
 :- use_module(doc).
 :- use_module(reaction_rules).
+:- use_module(util).
 :- use_module(library(yall)).
 
 :- op(1010, fx, init).  % comma is 1000
@@ -1420,9 +1421,10 @@ filter_denominator(X^Nr, Num, Den) :-
   (
     number(Nr)
   ->
-    N = Nr
+    util:try_to_cast_integer(Nr, N)
   ;
-    parameter_value(Nr, N)
+    parameter_value(Nr, Nt),
+    util:try_to_cast_integer(Nt, N)
   ),!,
   (
     N<0
@@ -1442,8 +1444,8 @@ filter_denominator(X^Nr, Num, Den) :-
     filter_denominator(X, Num, Den)
   ;
     filter_denominator(X, NumT, DenT),
-    maplist([X,Y]>>(Y = X^N), NumT, Num),
-    maplist([X,Y]>>(Y = X^N), DenT, Den)
+    maplist({N}/[X,Y]>>(Y = X^N), NumT, Num),
+    maplist({N}/[X,Y]>>(Y = X^N), DenT, Den)
   ).
 
 filter_denominator(X, [X], []).

util.pl

@@ -957,6 +957,21 @@ atom_to_int(String, Int) :-
   read_term_from_atom(String, Int, []),
   integer(Int).
 
+%! try_to_cast_integer(+Expr, -Result)
+%
+% Try to read Expr as an integer and return a float if it is not possible (discrepancy
+% higher than 1e-9)
+try_to_cast_integer(Expr, Result) :-
+  Putative_Float is Expr,
+  Putative_Int is integer(Putative_Float),
+  Discr is abs((Putative_Int-Putative_Float)/Putative_Float),
+  (
+    Discr < 1e-9
+  ->
+    Result = Putative_Int
+  ;
+    Result = Putative_Float
+  ).
 
 % what setof should have always been