Saving MatFIle in v73 requires much more time than v5 with the same data

[zhengliuer]

Hi, I am writing data(struct array format) in .mat file using matio(it is actually matio-cpp, cpp wrapper of matio), and I noticed that writing data in v73 requires about 5X time than in v5, is this as expected?

I am trying to give a sample code here, but the code still have some error I have not figured out. But I will put t here anyway. If I find why, I will update it.

#include <iostream>
#include <string>
#include <fstream>

#include <chrono>
#include <matiocpp/matioCpp.h>


int main(int argc, char** argv)
{
    std::string sDataPath = "data.mat";
    std::string sOutputV5 = "save_data_v5.mat";
    std::string sOutputV73 = "save_data_v73.mat";

    matioCpp::File matFile = matioCpp::File::Create(sDataPath, matioCpp::FileVersion::MAT7_3);
    matioCpp::StructArray data = matFile.read("data").asStructArray();


    auto startTime = std::chrono::high_resolution_clock::now();
    // Read data, save as v5
    matioCpp::File matFileV5 = matioCpp::File::Create(sOutputV5, matioCpp::FileVersion::MAT5);
    matFileV5.write(data);

    auto endV5Time = std::chrono::high_resolution_clock::now();
    uint64_t v5Duration_ms = std::chrono::duration_cast<std::chrono::milliseconds>(endV5Time - startTime).count();
    std::cout << "v5 writing cost " << v5Duration_ms << "ms\n";

    // Read data, save as v73
    matioCpp::File matFileV73 = matioCpp::File::Create(sOutputV73, matioCpp::FileVersion::MAT7_3);
    matFileV73.write(data);

    auto endV7Time = std::chrono::high_resolution_clock::now();
    uint64_t v73Duration_ms = std::chrono::duration_cast<std::chrono::milliseconds>(endV7Time - endV5Time).count();
    std::cout << "v73 writing cost " << v73Duration_ms << "ms\n";

}

data.txt
Remember rename the file to data.mat

Best,
Zheng

[tbeu]

@zhengliuer Why is it closed? Is it just no longer relevant?

[tbeu]

Here's a matio native test benchmark

#include <cstdlib>
#include <iostream>
#include <string>
#include <chrono>

#include "matio.h"

int main(int argc, char *argv[])
{
  std::string sDataPath = "data.mat";
  std::string sOutputV5 = "save_data_v5.mat";
  std::string sOutputV73 = "save_data_v73.mat";

  const auto matFileR = Mat_Open(sDataPath.c_str(), MAT_ACC_RDONLY);
  const auto data = Mat_VarRead(matFileR, "data");

  const auto bench = [&](const std::string& path, mat_ft ver, const char* verStr) {
    const auto startTime = std::chrono::high_resolution_clock::now();
    const auto matFileW = Mat_CreateVer(path.c_str(), nullptr, ver);
    Mat_VarWrite(matFileW, data, MAT_COMPRESSION_NONE);
    const auto endTime = std::chrono::high_resolution_clock::now();
    const auto duration_ms = std::chrono::duration_cast<std::chrono::milliseconds>(endTime - startTime).count();
    Mat_Close(matFileW);
    std::cout << verStr << " writing cost " << duration_ms << "ms\n";
  };

  bench(sOutputV5, MAT_FT_MAT5, "v5");
  bench(sOutputV73, MAT_FT_MAT73, "v73");

  Mat_VarFree(data);
  Mat_Close(matFileR);
}

I can confirm the performance degradtion with v73

v5 writing cost 56ms
v73 writing cost 337ms

[zhengliuer]

@zhengliuer Why is it closed? Is it just no longer relevant?

Because I was occupied by some other things before, and I couldn't find the bug of my code. Now I have time for this.

[zhengliuer]

The test result had a similar performance degradation with my program. For v73 using HDF5 format, I am not sure if this is the reason that costs much more time than v5.