metal : add XIELU unary op (ggml-org#20802)

Author: seyoungjeong

ggml/src/ggml-metal/ggml-metal-device.cpp

@@ -250,6 +250,7 @@ ggml_metal_pipeline_with_params ggml_metal_library_get_pipeline_unary(ggml_metal
                 case GGML_UNARY_OP_CEIL:        op_num = OP_UNARY_NUM_CEIL;        break;
                 case GGML_UNARY_OP_ROUND:       op_num = OP_UNARY_NUM_ROUND;       break;
                 case GGML_UNARY_OP_TRUNC:       op_num = OP_UNARY_NUM_TRUNC;       break;
+                case GGML_UNARY_OP_XIELU:       op_num = OP_UNARY_NUM_XIELU;       break;
                 default: GGML_ABORT("fatal error");
             } break;
         default: GGML_ABORT("fatal error");

ggml/src/ggml-metal/ggml-metal-device.m

@@ -1043,6 +1043,7 @@ bool ggml_metal_device_supports_op(ggml_metal_device_t dev, const struct ggml_te
                 case GGML_UNARY_OP_CEIL:
                 case GGML_UNARY_OP_ROUND:
                 case GGML_UNARY_OP_TRUNC:
+                case GGML_UNARY_OP_XIELU:
                     return ggml_is_contiguous_rows(op->src[0]) && (op->src[0]->type == GGML_TYPE_F32 || op->src[0]->type == GGML_TYPE_F16);
                 default:
                     return false;

ggml/src/ggml-metal/ggml-metal-impl.h

@@ -127,6 +127,7 @@
 #define OP_UNARY_NUM_CEIL        118
 #define OP_UNARY_NUM_ROUND       119
 #define OP_UNARY_NUM_TRUNC       120
+#define OP_UNARY_NUM_XIELU       121
 
 #define OP_SUM_ROWS_NUM_SUM_ROWS 10
 #define OP_SUM_ROWS_NUM_MEAN     11

ggml/src/ggml-metal/ggml-metal-ops.cpp

@@ -787,6 +787,13 @@ int ggml_metal_op_unary(ggml_metal_op_t ctx, int idx) {
         args.max = ggml_get_op_params_f32(op, 1);
     }
 
+    if (op->op == GGML_OP_UNARY && ggml_get_unary_op(op) == GGML_UNARY_OP_XIELU) {
+        args.slope = ggml_get_op_params_f32(op, 1); // alpha_n
+        args.scale = ggml_get_op_params_f32(op, 2); // alpha_p
+        args.bias  = ggml_get_op_params_f32(op, 3); // beta
+        args.val   = ggml_get_op_params_f32(op, 4); // eps
+    }
+
     auto pipeline = ggml_metal_library_get_pipeline_unary(lib, op);
 
     if (pipeline.c4) {

ggml/src/ggml-metal/ggml-metal.metal

@@ -1177,6 +1177,15 @@ kernel void kernel_unary_impl(
         if (FC_OP == OP_UNARY_NUM_TRUNC) {
             dst_ptr[i0] = (T) trunc(x);
         }
+
+        if (FC_OP == OP_UNARY_NUM_XIELU) {
+            const TC xi      = x;
+            const TC gate    = TC(xi > TC(0.0f));
+            const TC clamped = fmin(xi, TC(args.val));
+            const TC y_pos   = TC(args.scale) * xi * xi + TC(args.bias) * xi;
+            const TC y_neg   = (exp(clamped) - TC(1.0f) - xi) * TC(args.slope) + TC(args.bias) * xi;
+            dst_ptr[i0] = (T) (gate * y_pos + (TC(1.0f) - gate) * y_neg);
+        }
     }
 
 #undef FC_OP

tests/test-backend-ops.cpp

@@ -8506,6 +8506,9 @@ static std::vector<std::unique_ptr<test_case>> make_test_cases_eval() {
     test_cases.emplace_back(new test_cumsum(GGML_TYPE_F32, { 20481, 4, 1, 1 }));
 
     test_cases.emplace_back(new test_xielu());
+    test_cases.emplace_back(new test_xielu(GGML_TYPE_F16));
+    test_cases.emplace_back(new test_xielu(GGML_TYPE_F32, { 512, 16, 1, 1 }));
+    test_cases.emplace_back(new test_xielu(GGML_TYPE_F16, { 512, 16, 1, 1 }));
 
     test_cases.emplace_back(new test_tri(GGML_TRI_TYPE_LOWER));
     test_cases.emplace_back(new test_tri(GGML_TRI_TYPE_LOWER_DIAG));