Mul-Pow case

Author: shashi

src/polyform.jl

@@ -1,4 +1,4 @@
-export PolyForm, simplify_fractions
+export PolyForm, simplify_fractions, quick_cancel
 using Bijections
 using DynamicPolynomials: PolyVar
 
@@ -341,6 +341,27 @@ function quick_cancel(x::Mul, y)
     end
 end
 
+function quick_cancel(x::Mul, y::Pow)
+    if haskey(x.dict, y.base)
+        d = copy(x.dict)
+        if x.dict[y.base] > y.exp
+            d[y.base] -= y.exp
+            den = 1
+        elseif x.dict[y.base] == y.exp
+            delete!(d, y.base)
+            den = 1
+        else
+            den = Pow{symtype(y)}(y.base, y.exp-d[y.base])
+            delete!(d, y.base)
+        end
+        return Mul(symtype(x), x.coeff, d), den
+    else
+        return x, y
+    end
+end
+
+quick_cancel(x::Pow, y::Mul) = reverse(quick_cancel(y,x))
+
 quick_cancel(y, x::Mul) = reverse(quick_cancel(x,y))
 
 function quick_cancel(x::Mul, y::Mul)

test/polyform.jl

@@ -43,4 +43,6 @@ end
     @eqtest simplify_fractions(2x^3 * y / x) == 2y*x^2
     @eqtest simplify_fractions(x / (3(x^3)*y)) == simplify_fractions(1/(3*(y*x^2)))
     @eqtest simplify_fractions(2x / (3(x^3)*y)) == simplify_fractions(2/(3*(y*x^2)))
+    @eqtest simplify_fractions(x^2 / (3(x^3)*y)) == simplify_fractions(1/(3*(y*x)))
+    @eqtest simplify_fractions((3(x^3)*y) / x^2) == simplify_fractions(3*(y*x))
 end

test/rulesets.jl

@@ -42,7 +42,7 @@ end
     @eqtest simplify(a + b + 0*c + d) == simplify(a + b + d)
     @eqtest simplify(a * b * c^0 * d) == simplify(a * b * d)
     @eqtest simplify(a * b * 1*c * d) == simplify(a * b * c * d)
-    @eqtest repr(simplify_fractions(x^2.0/(x*y)^2.0)) == "1 / (y^2.0)"
+    @eqtest simplify_fractions(x^2.0/(x*y)^2.0) == simplify_fractions(1 / (y^2.0))
 
     @test simplify(Term(one, [a])) == 1
     @test simplify(Term(one, [b+1])) == 1