Length check before applying TensorProduct (#111)

* Length check before applying TensorProduct

* Change  error to thrown to DimensionMismatch

Author: sharanry

src/kernels/tensorproduct.jl

@@ -23,6 +23,10 @@ end
 Base.length(kernel::TensorProduct) = length(kernel.kernels)
 
 function (kernel::TensorProduct)(x, y)
+    if !(length(x) == length(y) == length(kernel))
+        throw(DimensionMismatch("number of kernels and number of features
+are not consistent"))
+    end
     return prod(k(xi, yi) for (k, xi, yi) in zip(kernel.kernels, x, y))
 end
 

test/kernels/tensorproduct.jl

@@ -13,6 +13,7 @@
 
     @test kernel1.kernels === (k1, k2) === TensorProduct((k1, k2)).kernels
     @test length(kernel1) == length(kernel2) == 2
+    @test_throws DimensionMismatch kernel1(rand(3), rand(3))
 
     @testset "val" begin
         for (x, y) in (((v1, u1), (v2, u2)), ([v1, u1], [v2, u2]))