Add symbolics_to_float converter

docs/src/manual/expression_manipulation.md

@@ -25,12 +25,12 @@ Other additional manipulation functions are given below.
 Symbolics.get_variables
 Symbolics.tosymbol
 Symbolics.diff2term
-Symbolics.solve_for
 Symbolics.degree
 Symbolics.coeff
 Symbolics.replace
 Symbolics.occursin
 Symbolics.filterchildren
 Symbolics.fixpoint_sub
 Symbolics.fast_substitute
+Symbolics.symbolic_to_float
 ```

src/utils.jl

@@ -414,3 +414,28 @@ symbolic expressions mapping variables w.r.t pvar2sym
 function poly_to_symbol(polys, pvar2sym, sym2term, ::Type{T}) where {T}
     map(f -> PolyForm{T}(f, pvar2sym, sym2term), polys)
 end
+
+"""
+    symbolic_to_float(x::Union{Num, BasicSymbolic})::Union{AbstractFloat, BasicSymbolic}
+
+If the symbolic value is exactly equal to a number, converts the symbolic value
+to a floating point number. Otherwise retains the symbolic value.
+
+## Examples
+
+```julia
+symbolic_to_float((1//2 * x)/x) # 0.5
+symbolic_to_float((1/2 * x)/x) # 0.5
+symbolic_to_float((1//2)*√(279//4)) # 4.175823272122517
+```
+"""
+function symbolic_to_float end
+symbolic_to_float(x::Num) = symbolic_to_float(unwrap(x))
+symbolic_to_float(x::Number) = x
+function symbolic_to_float(x::SymbolicUtils.BasicSymbolic)
+    if _x isa Number
+        return _x
+    else
+        substitute(x,Dict())
+    end
+end

test/runtests.jl

@@ -27,6 +27,7 @@ if GROUP == "All" || GROUP == "Core"
         @safetestset "Semi-polynomial" begin include("semipoly.jl") end
         @safetestset "Fuzz Arrays" begin include("fuzz-arrays.jl") end
         @safetestset "Differentiation Test" begin include("diff.jl") end
+        @safetestset "Utils Test" begin include("utils.jl") end
         @safetestset "ADTypes Test" begin include("adtypes.jl") end
         @safetestset "Difference Test" begin include("difference.jl") end
         @safetestset "Degree Test" begin include("degree.jl") end

test/utils.jl

@@ -1,4 +1,5 @@
 using Symbolics
+using Symbolics: symbolic_to_float
 
 @testset "get_variables" begin
     @variables t x y z(t)
@@ -19,3 +20,12 @@ using Symbolics
     sorted_vars2 = Symbolics.get_variables(ex2; sort = true)
     @test isequal(sorted_vars2, [x, y])
 end
+
+@testset "symbolic_to_float" begin
+    @variables x
+    symbolic_to_float((1//2 * x)/x) isa Float64
+    symbolic_to_float((1/2 * x)/x) isa Float64
+    symbolic_to_float((1//2)*√(279//4)) isa Float64
+    symbolic_to_float((big(1)//2)*√(279//4)) isa BigFloat
+    symbolic_to_float((-1//2)*√(279//4)) isa Float64
+end