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MatCL

MatCL is an OpenCL interface for MathWorks Matlab. This MEX-based toolbox aims at providing a simple and easy to use solution to transfer memory and launch OpenCL kernels from Matlab using a single command. In comparison to other Matlab OpenCL solutions, MatCL is not just an OpenCL API wrapper but encapsulates the low-level host API calls necessary to initialize devices, create OpenCL buffers from Matlab workspace variables and build and launch kernels. MatCL is primarily intended to help in the development and testing of OpenCL kernels by allowing to transparently pass data from and to Matlab. Because MatCL handles the entire low-level process, this toolbox makes it possible to execute kernels without in depth knowledge of the host implementation necessary to support the execution of OpenCL kernels. MatCL is also optimized to allow efficient execution of OpenCL kernels within Matlab to accelerate computationally intensive tasks without having to rely on Nvidia CUDA. In addition to single command kernel execution, MatCL also allows for an independent two-step kernel compilation and launch workflow to save the kernel compile time and allow efficient repetitive kernel execution.

A practical example for how MatCL can be used for scientific research is the Induction Equation project.

Tested using Nvidia (Tesla, GTX), AMD (Ryzen, Radeon R9, FirePro) and Intel (Xeon, Core, HD Graphics) devices with Matlab R2015b and up.

Usage

Usage information for the individual functions is available through the Matlab help command (e.g. help cl_get_devices) and the documentation browser (e.g. doc cl_get_devices).

• Enumerate OpenCL Devices (returns a list whose i-th entry corresponds to the i-th OpenCL device): [names,dev_class,max_mem,max_wg_size,max_local_work_size,compute_units]=cl_get_devices;

  • names: Names of all available devices
  • dev_class: The device class (CPU, GPU or Other for other or unknown Accelerators)
  • max_mem: The available device memory in bytes
  • max_wg_size: Max. size of OpenCL work group
  • max_local_work_size: Max. size of work items
  • compute_units: Number of compute units (e.g. CPU cores) of the device

• Build Kernel: [comp_time,kernels]=cl_run_kernel(ocl_dev_id,'kernel_url.cl','defines');

  • comp_time: Microseconds it took to compile the kernels

  • kernels: List with names of all available kernels

  • ocl_dev_id: ID of the OpenCL device to be used

  • kernel_url.cl: URL of the kernel file

  • defines: List of OpenCL compiler defines

• Run Kernel: [run_time,copy_time]=cl_run_kernel(ocl_dev_id,',{'kernel_function1','kernel_function2'},global_range,local_range,in1,out1,[rw_flags]);

  • run_time: Microseconds it took to execute the kernels

  • copy_time: Microseconds it took to copy all buffers

  • ocl_dev_id: ID of the OpenCL device to be used

  • kernel_function: Cell array of kernel functions to execute (can also be a single string for just one kernel)

  • global_range: 3D global OpenCL range (see NDRange). If this vector has six entires, the first three define the 3D work offset followed by the 3D work size.

  • local_range: 3D local OpenCL range (see NDRange)

  • in1, out1: List of variables to pass from/to kernel

  • rw_flags: read/write flag for the Kernel variables, this can either be scalar (all variables are read&write) or a vector with an entry for each variable: 0 - read&write / 1 - kernel read only / 2 - kernel write only

• Build & Run Kernel: [run_time]=cl_run_kernel(ocl_dev_id,'kernel_url.cl ','defines ','kernel_function',global_range,local_range,in1,out1,[rw_flags]);

  • run_time: Microseconds it took to execute the kernels

  • ocl_dev_id: ID of the OpenCL device to be used

  • kernel_url.cl: URL of the kernel file

  • defines: List of OpenCL compiler defines

  • kernel_function: Cell array of kernel functions to execute (can also be a single string for just one kernel)

  • global_range: 3D global OpenCL range (see NDRange). If this vector has six entires, the first three define the 3D work offset followed by the 3D work size.

  • local_range: Local OpenCL range (see NDRange)

  • in1, out1: List of variables to pass from/to kernel

  • rw_flags: read/write flag for the Kernel variables, this can either be scalar (all variables are read&write) or a vector with an entry for each variable: 0 - read&write / 1 - kernel read only / 2 - kernel write only

• Build & Run Kernel (with Kernel printf redirection): [run_time]=cl_dbg_kernel(ocl_dev_id,' kernel_url.cl ','defines ','kernel_function',global_range,local_range,in1,out1,[rw_flags]);

  • run_time: Microseconds it took to execute the kernels (might be slower due to printf redirection)

  • ocl_dev_id: ID of the OpenCL device to be used

  • kernel_url.cl: URL of the kernel file

  • defines: List of OpenCL compiler defines

  • kernel_function: Cell array of kernel functions to execute (can also be a single string for just one kernel)

  • global_range: 3D global OpenCL range (see NDRange). If this vector has six entires, the first three define the 3D work offset followed by the 3D work size.

  • local_range: Local OpenCL range (see NDRange)

  • in1, out1: List of variables to pass from/to kernel

  • rw_flags: read/write flag for the Kernel variables, this can either be scalar (all variables are read&write) or a vector with an entry for each variable: 0 - read&write / 1 - kernel read only / 2 - kernel write only

Setup

Just use git clone https://github.com/IANW-Projects/MatCL and run compile_linux.m, compile_windows.m, or compile_mac to compile MatCL. Depending on the OpenCL libraries used, the library path may have to be changed in these files. Than add the folder MatCL to the search path of Matlab. Alternatively, some precompiled binaries are available at https://github.com/IANW-Projects/MatCL/releases.

There may be problems with old C/C++ libraries supplied by Matlab under Linux, resulting in errors such as Invalid MEX-file '/..../cl_get_devices.mex64', followed by many missing symbols. If you use a Debian based system, install the package matlab-support via sudo apt-get install matlab-support and choose the option to rename the GCC libraries of Matlab during setup.

Reference

MatCL can be referenced using the DOI 10.1145/3204919.3204927 and the following bibtex entry.

@inproceedings{heinisch2018MatCL,
  title={{MatCL}: {A} new easy-to use {OpenCL} toolbox for {MathWorks} {Matlab}},
  author={Heinisch, Philip and Ostaszewski, Katharina},
  year={2018},
  pages={8:1--8:1},
  booktitle={Proceedings of the International Workshop on OpenCL},
  series={IWOCL '18, May 2018, Oxford (United Kingdom)},
  publisher={ACM},
  address={New York, NY, USA},
  note={\url{https://github.com/IANW-Projects/MatCL}},
  doi={10.1145/3204919.3204927}
}

The latest release can be cited with

@misc{MatCLGit,
  title={{MatCL}: {A} new easy-to use {OpenCL} toolbox for {MathWorks} {Matlab}},
  author={Heinisch, Philip and Ostaszewski, Katharina and Ranocha, Hendrik},
  month={01},
  year={2019},
  howpublished={\url{https://github.com/IANW-Projects/MatCL}},
  doi={10.5281/zenodo.2531474}
}

License

This project is licensed under the terms of the Creative Commons CC BY-NC-ND 4.0 license.

Disclaimer

Product and company names may be trademarks or registered trademarks of their respective holders. Use of them does not imply any affiliation with or endorsement by them or their affiliates. Everything is provided as is and without warranty. Use at your own risk!