# Source §4 Gpu

Source §4 GPU is a small programming language, designed to allow users to accelerate their programs by making use of their GPUs!

## What names are predeclared in Source §4 GPU?

On the right, you see all predeclared names of Source §4, in alphabetical order. Click on a name to see how it is used. They come in these two groups:

• MISC: Miscellaneous constants and functions
• MATH: Mathematical constants and functions
• LISTS: Support for lists
• PAIRMUTATORS: Mutating pairs
• ARRAYS: Support for arrays
• STREAMS: Support for streams
• MCE: Support for the meta-circular evaluator

## What can you do in Source §4 GPU?

You can write for loops as per normal source and if certain conditions are met, the GPU will be invoked to run the program!

### Example:

``````const size = 100;

const L = [];
const R = [];
for (let r = 0; r < size; r = r + 1) {
L[r] = [];
R[r] = [];
for (let c = 0; c < size; c = c + 1) {
L[r][c] = r*c;
R[r][c] = r + c;
}
}

const res = [];
for (let r = 0; r < size; r = r + 1) {
res[r] = [];
}

const startTime = get_time();
for (let r = 0; r < size; r = r + 1) {
for (let c = 0; c < size; c = c + 1) {
let sum = 0;
for (let i = 0; i < size; i = i + 1) {
sum = sum + L[r][i] * R[i][c];
}
res[r][c] = sum;
}
}

const endTime = get_time();
const elapsed = endTime - startTime;

display(res);
display(elapsed, "Time taken: ");
``````

## You want the definitive specs?

For our development team, we are maintaining a definitive description of the language, called the Specification of Source §4 GPU. Feel free to take a peek!