The Chapel Programming Language

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The Chapel Programming Language

Productive parallel computing at every scale.

writeln("Hello, world!"); // create a parallel task per processor core coforall tid in 0..<here.maxTaskPar do writeln("Hello from task ", tid); // print these 1,000 messages in parallel using all cores forall i in 1..1000 do writeln("Hello from iteration ", i);

// print a message per compute node coforall loc in Locales do on loc do writeln("Hello from locale ", loc.id); // print a message per core per compute node coforall loc in Locales do on loc do coforall tid in 0..<here.maxTaskPar do writeln("Hello from task ", tid, " on locale ", loc.id); // print 1,000 messages in parallel using all nodes and cores use BlockDist; const Inds = blockDist.createDomain(1..1000); forall i in Inds do writeln("Hello from iteration ", i, " running on locale ", here.id);

use IO; // read in a file containing 'city name;temperature' lines (1BRC-style) const stats = [line in stdin.lines()] new cityTemperature(line); writeln(stats); record cityTemperature { const city: string; // city name const temp: real; // temperature proc init(str: string) { const words = str.split(";"); this.city = words[0]; this.temp = words[1]: real; } }

// set different values at runtime with command line arguments // e.g. --n=2048 --numSteps=256 --alpha=0.8 config const n = 1000, numSteps = 100, alpha = 1.0; const fullDomain = {1..n}, interior = {2..n-1}; var u: [fullDomain] real = 1.0; u[n/4..3*n/4] = 2.0; // make the middle a bit hotter var un = u; for 1..numSteps { forall i in interior do // shared-memory parallelism u[i] = un[i] + alpha * (un[i-1] - 2*un[i] + un[i+1]); un <=> u; // swap the two arrays } writeln(un);

use Random, Math; const nGpus = here.gpus.size, n = Locales.size*nGpus; var A: [1..n, 1..n] real; fillRandom(A); // use all nodes coforall (loc, localRowStart) in zip(Locales, 1.. by nGpus) do on loc { // and all GPUs within each coforall (gpu, row) in zip(here.gpus, localRowStart..) do on gpu { var B: [1..n] real = A[row, ..]; // copy a row from device to host B = asin(B); // compute (kernel launch) A[row, ..] = B; // copy the row back } } writeln(A);

Users Love It

“

The use of Chapel worked as intended: the code maintenance is very much reduced, and its readability is astonishing. This enables undergraduate students to contribute to its development, something almost impossible to think of when using very complex software.

”

- Éric Laurendeau, Professor, Polytechnique Montréal

“

A lot of the nitty gritty is hidden from you until you need to know it. ... It feels like the complexity grows as you get more comfortable -- rather than being hit with everything at once.

”

- Tess Hayes, Developer, Bytoa

Chapel in Production

CHAMPS

World-class multiphysics simulation

Written by students and post-docs in Eric Laurendeau's lab at Polytechnique Montreal. Outperformed its C/OpenMP predecessor using far fewer lines of code. Dramatically accelerated the progress of grad students while also supporting contributions from undergrads for the first time.

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Arkouda

Interactive data science at massive scale

Familiar Python/Jupyter client interface, powered by a Chapel server that scales to compute and memory resources beyond any comparable tool. Interactively work with dozens of TBs of data.

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Coral Reef Biodiversity Analysis

Processing oceans of data

The Coral Reef Alliance uses Chapel to analyze satellite imagery of the Mesoamerican Barrier Reef System, providing biodiversity measurements 5 orders of magnitude faster than the previous solution.

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ChOp

Exact optimization algorithms at scale

Chapel-based Optimization (ChOp) solves combinatorial optimization problems. It leverages CPU-GPU heterogeneity with high productivity and parallel performance.

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ChplUltra

Ultralight dark matter simulation

Simulates the astrophysical dynamics of ultra-light dark matter using Chapel's productivity features to compute distributed FFTs. Scales to hundreds of nodes.

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Read Entire Article

The Chapel Programming Language

The Chapel Programming Language

Users Love It

- Éric Laurendeau, Professor, Polytechnique Montréal

- Tess Hayes, Developer, Bytoa

Chapel in Production

CHAMPS

World-class multiphysics simulation

Arkouda

Interactive data science at massive scale

Coral Reef Biodiversity Analysis

Processing oceans of data

ChOp

Exact optimization algorithms at scale

ChplUltra

Ultralight dark matter simulation

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