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#include <hip/hip_runtime.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <iostream>

#define TILE_DIM 16
#define BLOCK_ROWS 16

__global__ void transposeNaive(float *odata, float *idata, int width, int height) {
  int xIndex = blockIdx.x * TILE_DIM + threadIdx.x;
  int yIndex = blockIdx.y * TILE_DIM + threadIdx.y;

  int index_in = xIndex + width * yIndex;
  int index_out = yIndex + height * xIndex;

  for (int i = 0; i < TILE_DIM; i += BLOCK_ROWS) {
    odata[index_out + i] = idata[index_in + i * width];
  }
}

__global__ void transposeCoalesced(float *odata, float *idata, int width, int height) {
  __shared__ float tile[TILE_DIM][TILE_DIM];

  int xIndex = blockIdx.x * TILE_DIM + threadIdx.x;
  int yIndex = blockIdx.y * TILE_DIM + threadIdx.y;
  int index_in = xIndex + (yIndex)*width;

  xIndex = blockIdx.y * TILE_DIM + threadIdx.x;
  yIndex = blockIdx.x * TILE_DIM + threadIdx.y;
  int index_out = xIndex + (yIndex)*height;

  for (int i = 0; i < TILE_DIM; i += BLOCK_ROWS) {
    tile[threadIdx.y + i][threadIdx.x] = idata[index_in + i * width];
  }

  __syncthreads();

  for (int i = 0; i < TILE_DIM; i += BLOCK_ROWS) {
    odata[index_out + i * height] = tile[threadIdx.x][threadIdx.y + i];
  }
}

__global__ void transposeNoBankConflicts(float *odata, float *idata, int width, int height) {
  __shared__ float tile[TILE_DIM][TILE_DIM + 1];

  int xIndex = blockIdx.x * TILE_DIM + threadIdx.x;
  int yIndex = blockIdx.y * TILE_DIM + threadIdx.y;
  int index_in = xIndex + (yIndex)*width;

  xIndex = blockIdx.y * TILE_DIM + threadIdx.x;
  yIndex = blockIdx.x * TILE_DIM + threadIdx.y;
  int index_out = xIndex + (yIndex)*height;

  for (int i = 0; i < TILE_DIM; i += BLOCK_ROWS) {
    tile[threadIdx.y + i][threadIdx.x] = idata[index_in + i * width];
  }

  __syncthreads();

  for (int i = 0; i < TILE_DIM; i += BLOCK_ROWS) {
    odata[index_out + i * height] = tile[threadIdx.x][threadIdx.y + i];
  }
}

/**
 * fillRandom
 * fill array with random values
 */
__global__ void fillRandom(float* arrayPtr, int size) {
    int id = threadIdx.x + blockDim.x * blockIdx.x;
    uint32_t seed = 12345678;
    while (id < size) {
        seed = (seed<<3) ^ id;
        arrayPtr[id] = seed;
        id += blockDim.x * gridDim.x;
    }
}

int main(int argc, char * argv[])
{
    float* input = nullptr;
    float* output = nullptr;
    size_t width = 1024;
    size_t height = 1024;

    // Set input data to matrix A and matrix B
    hipMalloc((void**)&input, width * height * sizeof(float));
    hipMalloc((void**)&output, width * height * sizeof(float));

    fillRandom<<<256, 256>>>(input, width*height);
    hipDeviceSynchronize();

    dim3 block(width/TILE_DIM,height/TILE_DIM);
    dim3 threads(TILE_DIM,TILE_DIM);

    transposeNoBankConflicts<<<block, threads>>>(
        output,
        input,
        width,
        height
    );

    hipDeviceSynchronize();

    hipFree(input);
    hipFree(output);

    return 0;
}