rework round and trunc

Project.toml

@@ -1,6 +1,6 @@
 name = "SymPy"
 uuid = "24249f21-da20-56a4-8eb1-6a02cf4ae2e6"
-version = "1.1.6"
+version = "1.1.7"
 
 [deps]
 CommonEq = "3709ef60-1bee-4518-9f2f-acd86f176c50"

src/generic.jl

@@ -38,16 +38,34 @@ Base.mod(x::SymbolicObject, args...)= Mod(x, args...)
 # so we can compare numbers with ≈
 Base.rtoldefault(::Type{<:SymbolicObject}) = eps()
 
-function Base.round(x::Sym; kwargs...)
-    length(free_symbols(x)) > 0 && throw(ArgumentError("can't round a symbolic expression"))
-    round(N(x); kwargs...)
+
+# SymPy round only has a digits argument and errors on symbols
+# here we relax it a git
+function Base.round(x::Sym, r::RoundingMode=RoundNearest; digits=nothing, kwargs...)
+    x.is_number != true && return x
+    digits === nothing && return _round(x, r)
+    return x.round(digits)
+end
+_round(x::Sym, r::RoundingMode{:Nearest}) =  x.round()
+_round(x::Sym, r::RoundingMode) = begin
+    Sym(round(N(x), r))
+end
+function Base.round(::Type{T}, x::Sym, r::RoundingMode=RoundNearest) where {T <: Integer}
+    r != RoundToZero && (x = round(x, r))
+    convert(T, trunc(x))
 end
 
-function Base.trunc(x::Sym; kwargs...)
-    length(free_symbols(x)) > 0 && throw(ArgumentError("can't truncate a symbolic expression"))
-    trunc(N(x); kwargs...)
+
+#trunc(x) returns the nearest integral value of the same type as x whose absolute value is less than or equal to the absolute value of x.
+function Base.trunc(x::Sym)
+    x.is_real == true || return x
+    y = x.evalf().floor()
+    x.is_positive && return y
+    return 1 + y
 end
 
+
+
 # check on type of number
 # these are boolean: true/false; not tru/false/nothing,as in SymPy
 Base.isfinite(x::Sym) = !is_(:infinite, x)

test/test-ode.jl

@@ -1,7 +1,7 @@
 using SymPy
 using Test
 
-@testset "ODes" begin
+@testset "ODEs" begin
     ## ODEs
     x, a = Sym("x, a")
     F = SymFunction("F")

test/tests.jl

@@ -772,6 +772,21 @@ end
     @syms x
     ex = integrate(sqrt(1 + (1/x)^2), (x, 1/sympy.E, sympy.E))
     @test N(ex) ≈ 3.196198513599507
+
+    ## Issue #472
+    @syms x
+    a = Sym(1)/2
+    @test round(x) == x
+    @test round(a) == 0
+    @test round(a, RoundUp) == 1
+    @test round(PI; digits = 2) * 100 == 314  # this one is odd
+    @test trunc(x) == x
+    @test trunc(PI) == 3
+    @test trunc(-PI) == -3
+    @test typeof(trunc(PI)) == typeof(PI)
+    M = [PI -PI; a x]
+    @test round.(M) == [3 -3; 0 x]
+
 end
 
 @testset "generic programming, issue 223" begin