successfully test silu backward

tests/test-grad0.c

@@ -7,6 +7,9 @@
 
 #define MAX_NARGS 2
 
+
+#define GGML_SILU_FP16
+
 //
 // logging
 //
@@ -409,6 +412,27 @@ int main(int argc, const char ** argv) {
             }
         }
 
+        // silu
+        {
+            const int nargs = 1;
+
+            for (int ndims = 1; ndims <= 2; ++ndims) {
+                for (int i = 0; i < nargs; ++i) {
+                    x[i] = get_random_tensor(ctx0, ndims, ne, -1.0f, 1.0f);
+                    ggml_set_param(ctx0, x[i]);
+                }
+
+                struct ggml_tensor * f = ggml_sum(ctx0, ggml_silu(ctx0, x[0]));
+
+#ifdef GGML_SILU_FP16
+                // due to GGML_SILU_FP16 the finite difference method will be slightly wrong -> increase error bounds.
+                check_gradient("silu", ctx0, x, f, ndims, nargs, 1e-3f, 0.5, INFINITY); 
+#else
+                check_gradient("silu", ctx0, x, f, ndims, nargs, 1e-3f, 1e-3f, INFINITY); 
+#endif
+            }
+        }
+
         ggml_free(ctx0);
     }