SYCL Academy

Exercise 6: Vector Add

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In this exercise you will learn how add the values in two arrays and write the results to another array in parallel using parallel_for.

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1.) Create your queue

Create a queue to enqueue your kernel function to, remember to handle errors.

2. ) Create buffers

Create buffers to manage the data of the two input arrays and output array.

Remember to ensure the range provided to the buffer is the size of the arrays.

3. ) Create accessors

Create accessors to each of the buffers within the command group function.

4. ) Write the kernel function

Now enqueue parallel kernel function by calling parallel_for on the handler.

This function takes a range specifying the number of iterations of the kernel function to invoke and the kernel function itself must take an id which represents the current iteration.

The id can be used in the accessor subscript operator to access or assign to the corresponding element of data that the accessor represents.

Build And Execution Hints

For DPC++ (using the Intel DevCloud):

icpx -fsycl -o sycl-ex-6 -I../External/Catch2/single_include ../Code_Exercises/Exercise_06_Vector_Add/source.cpp

In Intel DevCloud, to run computational applications, you will submit jobs to a queue for execution on compute nodes, especially some features like longer walltime and multi-node computation is only available through the job queue. Please refer to the guide.

So wrap the binary into a script job_submission and run:

qsub job_submission

For ComputeCpp:

cmake -DSYCL_ACADEMY_USE_COMPUTECPP=ON -DSYCL_ACADEMY_INSTALL_ROOT=/insert/path/to/computecpp ..
make exercise_06_vector_add source
./Code_Exercises/Exercise_06_Vector_Add/exercise_06_vector_add source

For hipSYCL:

# <target specification> is a list of backends and devices to target, for example
# "omp;hip:gfx900,gfx906" compiles for CPUs with the OpenMP backend and for AMD Vega 10 (gfx900) and Vega 20 (gfx906) GPUs using the HIP backend.
# The simplest target specification is "omp" which compiles for CPUs using the OpenMP backend.
cmake -DSYCL_ACADEMY_USE_HIPSYCL=ON -DSYCL_ACADEMY_INSTALL_ROOT=/insert/path/to/hipsycl -DHIPSYCL_TARGETS="<target specification>" ..
make exercise_06_vector_add
./Code_Exercises/Exercise_06_Vector_Add/exercise_06_vector_add_source

alternatively, without cmake:

cd Code_Exercises/Exercise_06_Vector_Add
/path/to/hipsycl/bin/syclcc -o sycl-ex-6 -I../../External/Catch2/single_include --hipsycl-targets="<target specification>" source.cpp
./sycl-ex-6