Merge pull request #124 from ChrisRackauckas-Claude/fix-vector-expressions

Add error handling for vector expressions

Author: ChrisRackauckas

src/integral.jl

@@ -72,6 +72,11 @@ function integrate(eq, x = nothing;
         detailed = true)
     deprecation_warnings(; homotopy, use_optim)
 
+    # Check if eq is a vector/array expression and throw an error
+    if eq isa AbstractArray || eq isa AbstractVector
+        error("Vector expressions are not supported. Please use element-wise integration with `integrate.([expr1, expr2, ...], x)` instead.")
+    end
+
     eq = expand(eq)
 
     if x == nothing

test/runtests.jl

@@ -327,3 +327,21 @@ end
         num_trials = 10)
     @test n > 0
 end
+
+@testset "vector expression error handling" begin
+    @variables x α
+
+    # Test that vector expressions throw an appropriate error
+    @test_throws ErrorException("Vector expressions are not supported. Please use element-wise integration with `integrate.([expr1, expr2, ...], x)` instead.") integrate([x])
+    @test_throws ErrorException("Vector expressions are not supported. Please use element-wise integration with `integrate.([expr1, expr2, ...], x)` instead.") integrate([1, 2 * α], α)
+
+    # Test that scalar integration still works
+    @test integrate(x) == ((1//2)*(x^2), 0, 0)
+    @test integrate(2 * α, α) == (α^2, 0, 0)
+
+    # Test that element-wise integration works
+    results = integrate.([1, 2 * α], α)
+    @test length(results) == 2
+    @test results[1] == (α, 0, 0)
+    @test results[2] == (α^2, 0, 0)
+end