/**
 * llama.cpp - commit 8962422b1c6f9b8b15f5aeaea42600bcc2d44177 - do not edit this file
 *
 * MIT License
 *
 * Copyright (c) 2023-2024 The ggml authors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include "norm.cuh"

template <int block_size>
static __global__ void norm_f32(const float * x, float * dst, const int ncols, const float eps) {
    const int row = blockIdx.x*blockDim.y + threadIdx.y;
    const int tid = threadIdx.x;

    float2 mean_var = make_float2(0.f, 0.f);

    for (int col = tid; col < ncols; col += block_size) {
        const float xi = x[row*ncols + col];
        mean_var.x += xi;
        mean_var.y += xi * xi;
    }

    // sum up partial sums
    mean_var = warp_reduce_sum(mean_var);
    if (block_size > WARP_SIZE) {
        __shared__ float2 s_sum[32];
        int warp_id = threadIdx.x / WARP_SIZE;
        int lane_id = threadIdx.x % WARP_SIZE;
        if (lane_id == 0) {
            s_sum[warp_id] = mean_var;
        }
        __syncthreads();
        mean_var = s_sum[lane_id];
        mean_var = warp_reduce_sum(mean_var);
    }

    const float mean = mean_var.x / ncols;
    const float var = mean_var.y / ncols - mean * mean;
    const float inv_std = rsqrtf(var + eps);

    for (int col = tid; col < ncols; col += block_size) {
        dst[row*ncols + col] = (x[row*ncols + col] - mean) * inv_std;
    }
}

template <int block_size>
static __global__ void group_norm_f32(const float * x, float * dst, const int group_size, const int ne_elements, const float eps) {
    // blockIdx.x: num_groups idx
    // threadIdx.x: block_size idx
    int start = blockIdx.x * group_size;
    int end = start + group_size;

    start += threadIdx.x;

    if (end >= ne_elements) {
        end = ne_elements;
    }

    float tmp = 0.0f; // partial sum for thread in warp

    for (int j = start; j < end; j += block_size) {
        tmp += x[j];
    }

    tmp = warp_reduce_sum(tmp);
    if (block_size > WARP_SIZE) {
        __shared__ float s_sum[32];
        int warp_id = threadIdx.x / WARP_SIZE;
        int lane_id = threadIdx.x % WARP_SIZE;
        if (lane_id == 0) {
            s_sum[warp_id] = tmp;
        }
        __syncthreads();
        tmp = s_sum[lane_id];
        tmp = warp_reduce_sum(tmp);
    }

    float mean = tmp / group_size;
    tmp = 0.0f;

    for (int j = start; j < end; j += block_size) {
        float xi = x[j] - mean;
        dst[j] = xi;
        tmp += xi * xi;
    }

    tmp = warp_reduce_sum(tmp);
    if (block_size > WARP_SIZE) {
        __shared__ float s_sum[32];
        int warp_id = threadIdx.x / WARP_SIZE;
        int lane_id = threadIdx.x % WARP_SIZE;
        if (lane_id == 0) {
            s_sum[warp_id] = tmp;
        }
        __syncthreads();
        tmp = s_sum[lane_id];
        tmp = warp_reduce_sum(tmp);
    }

    float variance = tmp / group_size;
    float scale = rsqrtf(variance + eps);
    for (int j = start; j < end; j += block_size) {
        dst[j] *= scale;
    }
}

template <int block_size>
static __global__ void rms_norm_f32(const float * x, float * dst, const int ncols, const float eps) {
    const int row = blockIdx.x*blockDim.y + threadIdx.y;
    const int tid = threadIdx.x;

    float tmp = 0.0f; // partial sum for thread in warp

    for (int col = tid; col < ncols; col += block_size) {
        const float xi = x[row*ncols + col];
        tmp += xi * xi;
    }

    // sum up partial sums
    tmp = warp_reduce_sum(tmp);
    if (block_size > WARP_SIZE) {
        __shared__ float s_sum[32];
        int warp_id = threadIdx.x / WARP_SIZE;
        int lane_id = threadIdx.x % WARP_SIZE;
        if (lane_id == 0) {
            s_sum[warp_id] = tmp;
        }
        __syncthreads();
        tmp = s_sum[lane_id];
        tmp = warp_reduce_sum(tmp);
    }

    const float mean = tmp / ncols;
    const float scale = rsqrtf(mean + eps);

    for (int col = tid; col < ncols; col += block_size) {
        dst[row*ncols + col] = scale * x[row*ncols + col];
    }
}

static void norm_f32_cuda(const float * x, float * dst, const int ncols, const int nrows, const float eps, cudaStream_t stream) {
    GGML_ASSERT(ncols % WARP_SIZE == 0);
    if (ncols < 1024) {
        const dim3 block_dims(WARP_SIZE, 1, 1);
        norm_f32<WARP_SIZE><<<nrows, block_dims, 0, stream>>>(x, dst, ncols, eps);
    } else {
        const dim3 block_dims(1024, 1, 1);
        norm_f32<1024><<<nrows, block_dims, 0, stream>>>(x, dst, ncols, eps);
    }
}

static void group_norm_f32_cuda(const float * x, float * dst, const int num_groups, const float eps, const int group_size, const int ne_elements, cudaStream_t stream) {
    if (group_size < 1024) {
        const dim3 block_dims(WARP_SIZE, 1, 1);
        group_norm_f32<WARP_SIZE><<<num_groups, block_dims, 0, stream>>>(x, dst, group_size, ne_elements, eps);
    } else {
        const dim3 block_dims(1024, 1, 1);
        group_norm_f32<1024><<<num_groups, block_dims, 0, stream>>>(x, dst, group_size, ne_elements, eps);
    }
}

static void rms_norm_f32_cuda(const float * x, float * dst, const int ncols, const int nrows, const float eps, cudaStream_t stream) {
    GGML_ASSERT(ncols % WARP_SIZE == 0);
    if (ncols < 1024) {
        const dim3 block_dims(WARP_SIZE, 1, 1);
        rms_norm_f32<WARP_SIZE><<<nrows, block_dims, 0, stream>>>(x, dst, ncols, eps);
    } else {
        const dim3 block_dims(1024, 1, 1);
        rms_norm_f32<1024><<<nrows, block_dims, 0, stream>>>(x, dst, ncols, eps);
    }
}

void ggml_cuda_op_norm(ggml_backend_cuda_context & ctx, ggml_tensor * dst) {
    const ggml_tensor * src0 = dst->src[0];
    const float * src0_d = (const float *)src0->data;
    float * dst_d = (float *)dst->data;
    cudaStream_t stream = ctx.stream();

    GGML_ASSERT(ggml_is_contiguous(src0));

    GGML_ASSERT(src0->type == GGML_TYPE_F32);
    GGML_ASSERT( dst->type == GGML_TYPE_F32);

    const int64_t ne00 = src0->ne[0];
    const int64_t nrows = ggml_nrows(src0);

    float eps;
    memcpy(&eps, dst->op_params, sizeof(float));

    norm_f32_cuda(src0_d, dst_d, ne00, nrows, eps, stream);
}

void ggml_cuda_op_group_norm(ggml_backend_cuda_context & ctx, ggml_tensor * dst) {
    const ggml_tensor * src0 = dst->src[0];
    const float * src0_d = (const float *)src0->data;
    float * dst_d = (float *)dst->data;
    cudaStream_t stream = ctx.stream();

    GGML_ASSERT(ggml_is_contiguous(src0));

    GGML_ASSERT(src0->type == GGML_TYPE_F32);
    GGML_ASSERT( dst->type == GGML_TYPE_F32);

    int num_groups = dst->op_params[0];

    float eps;
    memcpy(&eps, dst->op_params + 1, sizeof(float));

    int group_size = src0->ne[0] * src0->ne[1] * ((src0->ne[2] + num_groups - 1) / num_groups);
    group_norm_f32_cuda(src0_d, dst_d, num_groups * src0->ne[3], eps, group_size, ggml_nelements(src0), stream);
}

void ggml_cuda_op_rms_norm(ggml_backend_cuda_context & ctx, ggml_tensor * dst) {
    const ggml_tensor * src0 = dst->src[0];
    const float * src0_d = (const float *)src0->data;
    float * dst_d = (float *)dst->data;
    cudaStream_t stream = ctx.stream();

    GGML_ASSERT(ggml_is_contiguous(src0));

    GGML_ASSERT(src0->type == GGML_TYPE_F32);
    GGML_ASSERT( dst->type == GGML_TYPE_F32);

    const int64_t ne00 = src0->ne[0];
    const int64_t nrows = ggml_nrows(src0);

    float eps;
    memcpy(&eps, dst->op_params, sizeof(float));

    rms_norm_f32_cuda(src0_d, dst_d, ne00, nrows, eps, stream);
}
