Added accumulate_param_gradients! tests.

Author: femtomc

test/modeling_library/switch.jl

@@ -192,12 +192,19 @@
     end
 
     @testset "accumulate parameter gradients" begin
-        tr = simulate(bam, (1, ))
-        zero_param_grad!(bang1, :std)
-        input_grads = accumulate_param_gradients!(tr, 1.0)
-        tr = simulate(bam, (2, ))
-        zero_param_grad!(fuzz1, :std)
-        input_grads = accumulate_param_gradients!(tr, 1.0)
+        for z in [1.0, 3.0, 5.0, 10.0]
+            chm = choicemap((:z, z))
+            tr, _ = generate(bam, (1, ), chm)
+            zero_param_grad!(bang1, :std)
+            input_grads = accumulate_param_gradients!(tr, 1.0)
+            expected_std_grad = logpdf_grad(normal, tr[:x => :z], 5.0 + 3.0, 3.0)[3]
+            @test isapprox(get_param_grad(bang1, :std), expected_std_grad)
+            tr, _ = generate(bam, (2, ), chm)
+            zero_param_grad!(fuzz1, :std)
+            input_grads = accumulate_param_gradients!(tr, 1.0)
+            expected_std_grad = logpdf_grad(normal, tr[:x => :z], 5.0 + 2 * 3.0, 3.0)[3]
+            @test isapprox(get_param_grad(fuzz1, :std), expected_std_grad)
+        end
     end
 
     # ------------ (More complex) hierarchy ------------ #