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 * Copyright � 2014 Advanced Micro Devices, Inc.                                    *
 * Copyright (c) 2015 Mark D. Hill and David A. Wood                                *
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#ifndef KERNEL_MAXMIN_H
#define KERNEL_MAXMIN_H

#include "hip/hip_runtime.h"

#define BIG_NUM 999999

/**
 * @brief   color kernel 1
 * @param   row         CSR pointer array
 * @param   col         CSR column array
 * @param   node_value  Vertex value array
 * @param   color_array Color value array
 * @param   stop        Termination variable
 * @param   max_d       Max array
 * @param   max_d       Min array
 * @param   color       Current color label
 * @param   num_nodes   Number of vertices
 * @param   num_edges   Number of edges
 */
__global__ void color1(int *row, int *col, int *node_value, int *color_array,
                       int *stop, int *max_d, int *min_d, const int color,
                       const int num_nodes, const int num_edges)
{
    // Get my workitem id
    int tid = blockIdx.x * blockDim.x + threadIdx.x;

    if (tid < num_nodes) {
        // If the vertex is not colored
        if (color_array[tid] == -1) {

            // Get the start and end pointers for the neighbor list
            int start = row[tid];
            int end;
            if (tid + 1 < num_nodes)
                end = row[tid + 1];
            else
                end = num_edges;

            int maximum = -1;
            int minimum = BIG_NUM;
            // Navigate the neighborlist
            for (int edge = start; edge < end; edge++) {
                if (color_array[col[edge]] == -1 && start != end - 1) {
                    *stop = 1;
                    // Determine if the vertex value is the maximum/minimum in the neighborhood
                    if (node_value[col[edge]] > maximum)
                        maximum = node_value[col[edge]];
                    if (node_value[col[edge]] < minimum)
                        minimum = node_value[col[edge]];
                }
            }
            // Assign the maximum/miminum value to max/min array
            max_d[tid] = maximum;
            min_d[tid] = minimum;
        }
    }
}

/**
 * @brief   color kernel 2
 * @param   node_value  Vertex value array
 * @param   color_array Color value array
 * @param   max_d       Max array
 * @param   min_d       Min array
 * @param   color       Current color label
 * @param   num_nodes   Number of vertices
 * @param   num_edges   Number of edges
 */
__global__ void color2(int *node_value, int *color_array, int *max_d,
                       int *min_d, const int color, const int num_nodes,
                       const int num_edges)
{
    // Get my workitem id
    int tid = blockIdx.x * blockDim.x + threadIdx.x;

    if (tid < num_nodes) {
        // If the vertex is still not colored
        if (color_array[tid] == -1) {
            // Assign a color
            if (node_value[tid] >= max_d[tid])
                color_array[tid] = color;
            if (node_value[tid] <= min_d[tid])
                color_array[tid] = color + 1;
        }
    }

}

/**
 * @brief   init kernel
 * @param   max_d       Max array
 * @param   min_d       Min array
 * @param   num_nodes   Number of vertices
 */
__global__ void ini(int *max_d, int *min_d, const int num_nodes)
{
    // Get my workitem id
    int tid = blockIdx.x * blockDim.x + threadIdx.x;

    // Initialize max: -1 and min: Big_num
    if (tid < num_nodes) {
        max_d[tid] = -1;
        min_d[tid] = BIG_NUM;
    }

}

#endif