Merge pull request #66 from JuliaSymbolics/myb/solve_for

Fix solve_for

Project.toml

@@ -1,7 +1,7 @@
 name = "Symbolics"
 uuid = "0c5d862f-8b57-4792-8d23-62f2024744c7"
 authors = ["Shashi Gowda <[email protected]>"]
-version = "0.1.1"
+version = "0.1.2"
 
 [deps]
 AbstractAlgebra = "c3fe647b-3220-5bb0-a1ea-a7954cac585d"

src/equations.jl

@@ -19,6 +19,9 @@ Base.show(io::IO, eq::Equation) = print(io, eq.lhs, " ~ ", eq.rhs)
 
 SymbolicUtils.simplify(x::Equation; kw...) = simplify(x.lhs; kw...) ~ simplify(x.rhs; kw...)
 
+lhss(xs) = map(x->x.lhs, xs)
+rhss(xs) = map(x->x.rhs, xs)
+
 """
 $(TYPEDSIGNATURES)
 

src/linear_algebra.jl

@@ -87,7 +87,8 @@ w.r.t `vars`.
 function solve_for(eqs, vars; simplify=true, check=true)
     A, b = A_b(eqs, vars, check)
     #TODO: we need to make sure that `solve_for(eqs, vars)` contains no `vars`
-    _solve(A, b, simplify)
+    sol = _solve(A, b, simplify)
+    sol isa AbstractArray ? map(Num, sol) : Num(sol)
 end
 
 function _solve(A::AbstractMatrix, b::AbstractArray, do_simplify)

test/overloads.jl

@@ -131,3 +131,12 @@ z2 = c + d * im
 @test real(a) === a
 @test conj(a) === a
 @test imag(a) === Num(0)
+
+@variables x y z
+eqs = [
+        2//1 * x + y - z ~ 2//1
+        2//1 + y - z ~ 3//1*x
+        2//1 + y - 2z ~ 3//1*z
+      ]
+@test [2 1 -1; -3 1 -1; 0 1 -5] * Symbolics.solve_for(eqs, [x, y, z]) == [2; -2; -2]
+@test isequal(Symbolics.solve_for(2//1*x + y - 2//1*z ~ 9//1*x, 1//1*x), 1//7*y - 2//7*z)