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Introduction to Parallel Programming using OpenCL

Zubair Nawaz (SESAME)

Giannis Ashiotis (ESRF)

Contents

• Why Parallel Programming

• Single core and Multicores

• GPU Architecture

• Introduction to OpenCL and pyOpenCL

• Introduction to pyFAI

• Work with pyFAI

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Why Parallel Programming ?

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Single Core

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Multicore

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CPU Vs GPU

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CPU Style core

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Slimming Down

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More Space: Double the Number of Cores

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…again

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And again…

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Saving yet more space

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Saving yet more space

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Gracious amount of parallelism

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Small or large device

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Heterogeneous System

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Installation of OpenCL, pyopencl and pyFAI

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INTRODUCTION OF PYFAISynchrotron Radiation Application

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Extra path traveled by incoming waves AY

Extra path traveled by scattered waves XB

X-Ray Diffraction

Constructive interference occurs(AY − XC) = n (n is an integer)

BRAGG’s EQUATION

d

dSin

The path difference between ray 1 and ray 2 = 2d Sin

For constructive interference: n = 2d Sin

Ray 1

Ray 2

Deviation = 2

Powder Diffraction

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What is a Powder?

• powder = polycrystalline solidlarge number of crystallites of mm length scale

• ideal powders (for diffraction) show random orientation of crystallites

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Powder Diffraction

a single crystal

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Tens of crystals hundreds of crystals

Powder Diffraction

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References

• http://www.matter.org.uk/

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