Skip to content

Latest commit

 

History

History
61 lines (48 loc) · 2.63 KB

GettingStarted.md

File metadata and controls

61 lines (48 loc) · 2.63 KB
Raw

Getting started

On recent Raspbian distributions, QPULib should work out-of-the-box. It's been tested on the Pi 1 Model B, the Pi 2, but not yet the Pi 3.

Building and running the GCD example

Try the commands below to build and run the GCD example.

sudo apt-get install git
git clone https://github.com/mn416/QPULib
cd QPULib/Tests
make QPU=1 GCD
sudo ./GCD

The QPU=1 flag to make indicates that the physical QPUs on the Raspberry Pi should be used to run QPULib kernels. Simply using make without QPU=1, or setting QPU to any value other than 1, will lead to emulation mode being used. As the name suggests, this means that QPU code will be emulated in software. This is useful for debugging, and also allows you to run QPULib programs on a PC if your Pi is not to hand. If you want to recompile with a different flag then do a make clean first.

Strictly speaking, any program that works in emulation mode but not on the Pi's physical QPUs is probably a bug in QPULib and should be reported, although there may be valid explanations for such differences.

Other examples

Here is a quick overview of some the other examples, which can be built in the same way as GCD:

Example Description Output
GCD Euclid's algorithm The GCD's of some random pairs of integers
Tri Computes triangular numbers The first 16 triangular numbers
MultiTri Like Tri, but uses 4 QPUs instead of 1 The first 64 triangular numbers
TriFloat Like Tri but casts floats to integers and back The first 16 triangular numbers
OET Odd-even transposition sorter 32 integers, sorted
HeatMap Modelling heat flow across a 2D surface An image in pgm format, and the time taken
Rot3D 3D rotation of a random object The time taken
AutoTest: specification-based testing of the compiler

Another program in the Tests directory worth mentioning is AutoTest: it generates random QPULib programs, runs them on the both source language interpreter and the target language emulator, and checks for equivalance. Currently, it only works in emulation mode.

CPU/GPU memory split

Depending on your plans, it may be useful to ensure that plenty of memory is available to the GPU. This can be done by using raspi-config, selecting Advanced Options and then Memory Split: (On a Raspberry Pi 1 Model B, 32M seems to be the minimum that works for me.)