ggml : add `GGML_PAD_REFLECT_1D` operation (ggml/1034)

* ggml_pad_reflect_1d defined in header

* implemented on CPU

* called the forward pass

* impl Metal kernel

* added Metal kernel

* added OP_PAD_REFLECT_1D in test-backend-ops.cpp

* add test-pad-reflect-1d test case

* test case support multiple backend

ggml/include/ggml.h

@@ -499,6 +499,7 @@ extern "C" {
         GGML_OP_POOL_2D_BACK,
         GGML_OP_UPSCALE, // nearest interpolate
         GGML_OP_PAD,
+        GGML_OP_PAD_REFLECT_1D,
         GGML_OP_ARANGE,
         GGML_OP_TIMESTEP_EMBEDDING,
         GGML_OP_ARGSORT,
@@ -1695,6 +1696,13 @@ extern "C" {
             int                  p2,
             int                  p3);
 
+    // pad each dimension with reflection: [a, b, c, d] -> [b, a, b, c, d, c]
+    GGML_API struct ggml_tensor * ggml_pad_reflect_1d(
+            struct ggml_context * ctx,
+            struct ggml_tensor  * a,
+            int                   p0,
+            int                   p1);
+
     // Ref: https://github.com/CompVis/stable-diffusion/blob/main/ldm/modules/diffusionmodules/util.py#L151
     // timesteps: [N,]
     // return: [N, dim]

ggml/src/ggml-cpu/ggml-cpu.c

@@ -10439,6 +10439,40 @@ static void ggml_compute_forward_pad(
     }
 }
 
+// ggml_compute_forward_pad_reflect_1d
+
+static void ggml_compute_forward_pad_reflect_1d(
+        const struct ggml_compute_params * params,
+              struct ggml_tensor * dst) {
+
+    const struct ggml_tensor * src0 = dst->src[0];
+
+    GGML_ASSERT(src0->type == GGML_TYPE_F32);
+    GGML_ASSERT( dst->type == GGML_TYPE_F32);
+
+    const int ith = params->ith;
+    const int nth = params->nth;
+
+    const int32_t * opts = (const int32_t *) dst->op_params;
+    const int p0 = opts[0];
+    const int p1 = opts[1];
+
+    GGML_TENSOR_UNARY_OP_LOCALS
+
+    for (int64_t i3 = 0; i3 < ne3; i3++) {
+        for (int64_t i2 = 0; i2 < ne2; i2++) {
+            for (int64_t i1 = ith; i1 < ne1; i1 += nth) {
+                float * left  = (float *) ((char *) dst->data + i3*nb3 + i2*nb2 + i1*nb1 +         p0*nb0);
+                float * right = (float *) ((char *) dst->data + i3*nb3 + i2*nb2 + i1*nb1 + (ne0-p1-1)*nb0);
+
+                ggml_vec_cpy_f32(ne00, left, (float *) ((char *) src0->data + i3*nb03 + i2*nb02 + i1*nb01));
+
+                for (int i0 = 1; i0 <= p0; i0++) { left[-i0] = left[i0];   }
+                for (int i0 = 1; i0 <= p1; i0++) { right[i0] = right[-i0]; }
+            }
+        }
+    }
+}
 
 // ggml_compute_forward_arange
 
@@ -12535,6 +12569,10 @@ static void ggml_compute_forward(struct ggml_compute_params * params, struct ggm
             {
                 ggml_compute_forward_pad(params, tensor);
             } break;
+        case GGML_OP_PAD_REFLECT_1D:
+            {
+                ggml_compute_forward_pad_reflect_1d(params, tensor);
+            } break;
         case GGML_OP_ARANGE:
             {
                 ggml_compute_forward_arange(params, tensor);
@@ -12877,6 +12915,7 @@ static int ggml_get_n_tasks(struct ggml_tensor * node, int n_threads) {
             } break;
         case GGML_OP_UPSCALE:
         case GGML_OP_PAD:
+        case GGML_OP_PAD_REFLECT_1D:
         case GGML_OP_ARANGE:
         case GGML_OP_TIMESTEP_EMBEDDING:
         case GGML_OP_ARGSORT:

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

@@ -310,6 +310,7 @@ enum ggml_metal_kernel_type {
     GGML_METAL_KERNEL_TYPE_CONV_TRANSPOSE_1D_F16_F32,
     GGML_METAL_KERNEL_TYPE_UPSCALE_F32,
     GGML_METAL_KERNEL_TYPE_PAD_F32,
+    GGML_METAL_KERNEL_TYPE_PAD_REFLECT_1D_F32,
     GGML_METAL_KERNEL_TYPE_ARANGE_F32,
     GGML_METAL_KERNEL_TYPE_TIMESTEP_EMBEDDING_F32,
     GGML_METAL_KERNEL_TYPE_ARGSORT_F32_I32_ASC,
@@ -877,6 +878,7 @@ static struct ggml_backend_metal_context * ggml_metal_init(ggml_backend_dev_t de
         GGML_METAL_ADD_KERNEL(GGML_METAL_KERNEL_TYPE_CONV_TRANSPOSE_1D_F16_F32,     conv_transpose_1d_f16_f32,      true);
         GGML_METAL_ADD_KERNEL(GGML_METAL_KERNEL_TYPE_UPSCALE_F32,                   upscale_f32,                    true);
         GGML_METAL_ADD_KERNEL(GGML_METAL_KERNEL_TYPE_PAD_F32,                       pad_f32,                        true);
+        GGML_METAL_ADD_KERNEL(GGML_METAL_KERNEL_TYPE_PAD_REFLECT_1D_F32,            pad_reflect_1d_f32,             true);
         GGML_METAL_ADD_KERNEL(GGML_METAL_KERNEL_TYPE_TIMESTEP_EMBEDDING_F32,        timestep_embedding_f32,         true);
         GGML_METAL_ADD_KERNEL(GGML_METAL_KERNEL_TYPE_ARANGE_F32,                    arange_f32,                     true);
         GGML_METAL_ADD_KERNEL(GGML_METAL_KERNEL_TYPE_ARGSORT_F32_I32_ASC,           argsort_f32_i32_asc,            true);
@@ -1099,6 +1101,7 @@ static bool ggml_metal_supports_op(const struct ggml_backend_metal_device_contex
         case GGML_OP_POOL_2D:
         case GGML_OP_UPSCALE:
         case GGML_OP_PAD:
+        case GGML_OP_PAD_REFLECT_1D:
         case GGML_OP_ARANGE:
         case GGML_OP_TIMESTEP_EMBEDDING:
         case GGML_OP_ARGSORT:
@@ -3258,6 +3261,38 @@ static void ggml_metal_encode_node(
 
                 const int nth = MIN(1024, ne0);
 
+                [encoder dispatchThreadgroups:MTLSizeMake(ne1, ne2, ne3) threadsPerThreadgroup:MTLSizeMake(nth, 1, 1)];
+            } break;
+        case GGML_OP_PAD_REFLECT_1D:
+            {
+                GGML_ASSERT(src0->type == GGML_TYPE_F32);
+
+                const int32_t p0 = ((const int32_t *)(dst->op_params))[0];
+                const int32_t p1 = ((const int32_t *)(dst->op_params))[1];
+
+                id<MTLComputePipelineState> pipeline = ctx->kernels[GGML_METAL_KERNEL_TYPE_PAD_REFLECT_1D_F32].pipeline;
+
+                [encoder setComputePipelineState:pipeline];
+                [encoder setBuffer:id_src0 offset:offs_src0 atIndex:0];
+                [encoder setBuffer:id_dst  offset:offs_dst  atIndex:1];
+                [encoder setBytes:&ne00 length:sizeof(ne00) atIndex:2];
+                [encoder setBytes:&ne01 length:sizeof(ne01) atIndex:3];
+                [encoder setBytes:&ne02 length:sizeof(ne02) atIndex:4];
+                [encoder setBytes:&ne03 length:sizeof(ne03) atIndex:5];
+                [encoder setBytes:&ne0  length:sizeof(ne0)  atIndex:6];
+                [encoder setBytes:&nb00 length:sizeof(nb00) atIndex:7];
+                [encoder setBytes:&nb01 length:sizeof(nb01) atIndex:8];
+                [encoder setBytes:&nb02 length:sizeof(nb02) atIndex:9];
+                [encoder setBytes:&nb03 length:sizeof(nb03) atIndex:10];
+                [encoder setBytes:&nb0  length:sizeof(nb0)  atIndex:11];
+                [encoder setBytes:&nb1  length:sizeof(nb1)  atIndex:12];
+                [encoder setBytes:&nb2  length:sizeof(nb2)  atIndex:13];
+                [encoder setBytes:&nb3  length:sizeof(nb3)  atIndex:14];
+                [encoder setBytes:&p0   length:sizeof(p0)   atIndex:15];
+                [encoder setBytes:&p1   length:sizeof(p1)   atIndex:16];
+
+                const int nth = MIN(1024, ne0);
+
                 [encoder dispatchThreadgroups:MTLSizeMake(ne1, ne2, ne3) threadsPerThreadgroup:MTLSizeMake(nth, 1, 1)];
             } break;
         case GGML_OP_ARANGE:

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

@@ -2897,6 +2897,53 @@ kernel void kernel_pad_f32(
     }
 }
 
+kernel void kernel_pad_reflect_1d_f32(
+    device  const char * src0,
+    device        char * dst,
+    constant   int64_t & ne00,
+    constant   int64_t & ne01,
+    constant   int64_t & ne02,
+    constant   int64_t & ne03,
+    constant   int64_t & ne0,
+    constant  uint64_t & nb00,
+    constant  uint64_t & nb01,
+    constant  uint64_t & nb02,
+    constant  uint64_t & nb03,
+    constant  uint64_t & nb0,
+    constant  uint64_t & nb1,
+    constant  uint64_t & nb2,
+    constant  uint64_t & nb3,
+    constant   int32_t & p0,
+    constant   int32_t & p1,
+    uint3 tgpig[[threadgroup_position_in_grid]],
+    uint3  tgpg[[threadgroups_per_grid]],
+    uint3 tpitg[[thread_position_in_threadgroup]],
+    uint3   ntg[[threads_per_threadgroup]]) {
+
+    const int64_t i3 = tgpig.z;
+    const int64_t i2 = tgpig.y;
+    const int64_t i1 = tgpig.x;
+
+    const int64_t i03 = i3;
+    const int64_t i02 = i2;
+    const int64_t i01 = i1;
+
+    device const float * src0_ptr = (device const float *) (src0 + i03*nb03 + i02*nb02 + i01*nb01);
+    device       float * dst_ptr  = (device       float *) (dst  +  i3*nb3  +  i2*nb2  +  i1*nb1);
+
+    if (i1 < ne01 && i2 < ne02 && i3 < ne03) {
+        for (int i0 = tpitg.x; i0 < ne0; i0 += ntg.x) {
+            if (i0 < p0) {
+                dst_ptr[i0] = src0_ptr[p0 - i0];
+            } else if (i0 < ne0 - p1) {
+                dst_ptr[i0] = src0_ptr[i0 - p0];
+            } else {
+                dst_ptr[i0] = src0_ptr[(ne0 - p1 - p0) - (p1 + 1 - (ne0 - i0)) - 1];
+            }
+        }
+    }
+}
+
 kernel void kernel_arange_f32(
     device        char * dst,
     constant   int64_t & ne0,

ggml/src/ggml.c

@@ -950,6 +950,7 @@ static const char * GGML_OP_NAME[GGML_OP_COUNT] = {
     "POOL_2D_BACK",
     "UPSCALE",
     "PAD",
+    "PAD_REFLECT_1D",
     "ARANGE",
     "TIMESTEP_EMBEDDING",
     "ARGSORT",
@@ -983,7 +984,7 @@ static const char * GGML_OP_NAME[GGML_OP_COUNT] = {
     "OPT_STEP_ADAMW",
 };
 
-static_assert(GGML_OP_COUNT == 81, "GGML_OP_COUNT != 81");
+static_assert(GGML_OP_COUNT == 82, "GGML_OP_COUNT != 82");
 
 static const char * GGML_OP_SYMBOL[GGML_OP_COUNT] = {
     "none",
@@ -1045,6 +1046,7 @@ static const char * GGML_OP_SYMBOL[GGML_OP_COUNT] = {
     "pool_2d_back(x)",
     "upscale(x)",
     "pad(x)",
+    "pad_reflect_1d(x)",
     "arange(start, stop, step)",
     "timestep_embedding(timesteps, dim, max_period)",
     "argsort(x)",
@@ -1078,7 +1080,7 @@ static const char * GGML_OP_SYMBOL[GGML_OP_COUNT] = {
     "adamw(x)",
 };
 
-static_assert(GGML_OP_COUNT == 81, "GGML_OP_COUNT != 81");
+static_assert(GGML_OP_COUNT == 82, "GGML_OP_COUNT != 82");
 
 static_assert(GGML_OP_POOL_COUNT == 2, "GGML_OP_POOL_COUNT != 2");
 
@@ -4097,6 +4099,37 @@ struct ggml_tensor * ggml_pad(
     return result;
 }
 
+// ggml_pad_reflect_1d
+
+struct ggml_tensor * ggml_pad_reflect_1d(
+        struct ggml_context * ctx,
+        struct ggml_tensor  * a,
+        int                   p0,
+        int                   p1) {
+    GGML_ASSERT(p0 >= 0);
+    GGML_ASSERT(p1 >= 0);
+
+    GGML_ASSERT(p0 < a->ne[0]); // padding length on each size must be less than the
+    GGML_ASSERT(p1 < a->ne[0]); // existing length of the dimension being padded
+
+    GGML_ASSERT(ggml_is_contiguous(a));
+    GGML_ASSERT(a->type == GGML_TYPE_F32);
+
+    struct ggml_tensor * result = ggml_new_tensor_4d(ctx, a->type,
+            a->ne[0] + p0 + p1,
+            a->ne[1],
+            a->ne[2],
+            a->ne[3]);
+
+    int32_t params[] = { p0, p1 };
+    ggml_set_op_params(result, params, sizeof(params));
+
+    result->op     = GGML_OP_PAD_REFLECT_1D;
+    result->src[0] = a;
+
+    return result;
+}
+
 // ggml_arange
 
 struct ggml_tensor * ggml_arange(