Merge remote-tracking branch 'origin/master'

Author: shashi

page/interface.md

@@ -40,14 +40,14 @@ for `simplify` to work. Other required methods are `operation` and `istree`
 
 In addition, the methods for `Base.hash` and `Base.isequal` should also be implemented by the types for the purposes of substitution and equality matching respectively.
 
-### Optional
-
-#### `similarterm(t::MyType, f, args)`
+#### `similarterm(t::MyType, f, args[, T])`
 
-Construct a new term with the operation `f` and arguments `args`, the term should be similar to `t` in type. if `t` is a `Term` object a new Term is created with the same symtype as `t`. If not, the result is computed as `f(args...)`. Defining this method for your term type will reduce any performance loss in performing `f(args...)` (esp. the splatting, and redundant type computation).
+Construct a new term with the operation `f` and arguments `args`, the term should be similar to `t` in type. if `t` is a `Term` object a new Term is created with the same symtype as `t`. If not, the result is computed as `f(args...)`. Defining this method for your term type will reduce any performance loss in performing `f(args...)` (esp. the splatting, and redundant type computation). T is the symtype of the output term. You can use `promote_symtype` to infer this type.
 
 The below two functions are internal to SymbolicUtils
 
+### Optional
+
 #### `symtype(x)`
 
 The supposed type of values in the domain of x. Tracing tools can use this type to

src/abstractalgebra.jl

@@ -23,9 +23,9 @@ function labels!(dicts, t)
         return t
     elseif istree(t) && (operation(t) == (*) || operation(t) == (+) || operation(t) == (-))
         tt = arguments(t)
-        return similarterm(t, operation(t), map(x->labels!(dicts, x), tt))
+        return similarterm(t, operation(t), map(x->labels!(dicts, x), tt), symtype(t))
     elseif istree(t) && operation(t) == (^) && length(arguments(t)) > 1 && isnonnegint(arguments(t)[2])
-        return similarterm(t, operation(t), map(x->labels!(dicts, x), arguments(t)))
+        return similarterm(t, operation(t), map(x->labels!(dicts, x), arguments(t)), symtype(t))
     else
         sym2term, term2sym = dicts
         if haskey(term2sym, t)
@@ -36,7 +36,8 @@ function labels!(dicts, t)
             sym = Sym{symtype(t)}(gensym(nameof(operation(t))))
             dicts2 = _dicts(dicts[2])
             sym2term[sym] = similarterm(t, operation(t),
-                                        map(x->to_mpoly(x, dicts)[1], arguments(t)))
+                                        map(x->to_mpoly(x, dicts)[1], arguments(t)),
+                                        symtype(t))
         else
             sym = Sym{symtype(t)}(gensym("literal"))
             sym2term[sym] = t
@@ -110,7 +111,7 @@ function _to_term(reference, x::MPoly, dict, syms)
         elseif length(monics) == 0
             return 1
         else
-            return similarterm(reference, *, monics)
+            return similarterm(reference, *, monics, symtype(reference))
         end
     end
 
@@ -123,15 +124,16 @@ function _to_term(reference, x::MPoly, dict, syms)
         t = similarterm(reference,
                         +,
                         map((x,y)->isone(y) ? x : Int(y)*x,
-                            monoms, x.coeffs[1:length(monoms)]))
+                            monoms, x.coeffs[1:length(monoms)]),
+                        symtype(reference))
     end
 
     substitute(t, dict, fold=false)
 end
 
 function _to_term(reference, x, dict, vars)
     if istree(x)
-        t=similarterm(x, operation(x), _to_term.((reference,), arguments(x), (dict,), (vars,)))
+        t=similarterm(x, operation(x), _to_term.((reference,), arguments(x), (dict,), (vars,)), symtype(x))
     else
         if haskey(dict, x)
             return dict[x]

src/types.jl

@@ -74,7 +74,7 @@ end
 function to_symbolic(x)
     Base.depwarn("`to_symbolic(x)` is deprecated, define the interface for your " *
                  "symbolic structure using `istree(x)`, `operation(x)`, `arguments(x)` " *
-                 "and `similarterm(::YourType, f, args)`", :to_symbolic, force=true)
+                 "and `similarterm(::YourType, f, args, symtype)`", :to_symbolic, force=true)
 
     x
 end
@@ -319,13 +319,23 @@ function term(f, args...; type = nothing)
 end
 
 """
-    similarterm(t, f, args)
+    similarterm(t, f, args, symtype)
 
-Create a term that is similar in type to `t` such that `symtype(similarterm(f,
-args...)) === symtype(f(args...))`.
+Create a term that is similar in type to `t`. Extending this function allows packages
+using their own expression types with SymbolicUtils to define how new terms should
+be created.
+
+## Arguments
+
+- `t` the reference term to use to create similar terms
+- `f` is the operation of the term
+- `args` is the arguments
+- The `symtype` of the resulting term. Best effort will be made to set the symtype of the
+  resulting similar term to this type.
 """
-similarterm(t, f, args) = f(args...)
-similarterm(::Term, f, args) = term(f, args...)
+similarterm(t, f, args, symtype) = f(args...)
+similarterm(t, f, args) = similarterm(t, f, args, _promote_symtype(f, args))
+similarterm(::Term, f, args, symtype=nothing) = term(f, args...; type=symtype)
 
 node_count(t) = istree(t) ? reduce(+, node_count(x) for x in  arguments(t), init=0) + 1 : 1
 
@@ -757,15 +767,16 @@ function mapvalues(f, d1::AbstractDict)
     d
 end
 
-function similarterm(p::Union{Mul, Add, Pow}, f, args)
-    if f === (+)
+function similarterm(p::Union{Mul, Add, Pow}, f, args, T=nothing)
+    if T === nothing
         T = _promote_symtype(f, args)
+    end
+    if f === (+)
         Add(T, makeadd(1, 0, args...)...)
     elseif f == (*)
-        T = _promote_symtype(f, args)
         Mul(T, makemul(1, args...)...)
     elseif f == (^) && length(args) == 2
-        Pow(args...)
+        Pow{T, typeof.(args)...}(args...)
     else
         f(args...)
     end

test/nf.jl

@@ -1,11 +1,16 @@
 using SymbolicUtils, Test
-using SymbolicUtils: polynormalize, Term
+using SymbolicUtils: polynormalize, Term, symtype
 @testset "polyform" begin
     @syms a b c d
     @test polynormalize(a * (b + -1 * c) + -1 * (b * a + -1 * c * a)) == 0
     @eqtest polynormalize(sin(a+b)+sin(c+d)) == sin(a+b) + sin(c+d)
     @eqtest simplify(polynormalize(sin((a+b)^2)^2)) == simplify(sin(a^2+2*(b*a)+b^2)^2)
     @test simplify(polynormalize(sin((a+b)^2)^2 + cos((a+b)^2)^2)) == 1
+    @syms x1::Real f(::Real)::Real
+
+    # issue 193
+    @test isequal(polynormalize(f(x1 + 2.0)), f(2.0 + x1))
+    @test symtype(polynormalize(f(x1 + 2.0))) == Real
 
     # cleanup rules
     @test polynormalize(Term{Number}(identity, 0)) == 0