Porting code to OpenMP offloading

Questions

• When and why should I use OpenMP offloading in my code?

• TODO

Objectives

• Understand TODO

• Understand TODO

• Understand

• Understand

Prerequisites

1. TODO

2. TODO

First heading

Some text

Second heading

Some more text, with a figure

This is a sample image

Exercise

TODO get the students to think about the content and answer a Zoom quiz

Solution

Hide the answer and reasoning in here

Some source code

Sometimes we need to look at code, which can be in the webpage and optionally you can pull out only some lines, or highlight others. Make sure both C++ and Fortran examples exist and work.

The field data structure

C++Fortran

struct field {
    // nx and ny are the dimensions of the field. The array data
    // contains also ghost layers, so it will have dimensions nx+2 x ny+2
    int nx;
    int ny;
    // Size of the grid cells
    double dx;
    double dy;
    // The temperature values in the 2D grid
    std::vector<double> data;
};

Building the code

If there’s terminal output to discuss, show something like:

nvc++ -g -O3 -fopenmp -Wall -I../common -c main.cpp -o main.o
nvc++ -g -O3 -fopenmp -Wall -I../common -c core.cpp -o core.o
nvc++ -g -O3 -fopenmp -Wall -I../common -c setup.cpp -o setup.o
nvc++ -g -O3 -fopenmp -Wall -I../common -c utilities.cpp -o utilities.o
nvc++ -g -O3 -fopenmp -Wall -I../common -c io.cpp -o io.o
nvc++ -g -O3 -fopenmp -Wall -I../common main.o core.o setup.o utilities.o io.o ../common/pngwriter.o -o heat_serial  -lpng

Running the code

To show a sample command line, use this approach

./heat_serial 800 800 1000

Keypoints

• TODO summarize the learning outcome

• TODO