chapel

Continuing my Chapel adventures... I have a matrix A. var idx = {1..n}; var adom = {idx, idx}; var A: [adom] int; //populate A; var rowsums: [idx] int; What is the most efficient way to populate rowsums? The most efficient solution is hard to define. However, here is one way to compute rowsums that is both parallel and elegant: config const n = 8; // "naked" n would cause compilation to fail const indices = 1..n; // tio.chpl:1: error: 'n' undeclared (first use this function) const adom = {indices, indices}; var A: [adom] int; // Populate A [(i,j) in adom] A[i, j] = i*j; var rowsums: [indices]

I'm populating a sparse array in Chapel with a loop that is reading over a CSV. I'm wondering what the best pattern is. var dnsDom = {1..n_dims, 1..n_dims}; var spsDom: sparse subdomain(dnsDom); for line in file_reader.lines() { var i = line[1]:int; var j = line[2]:int; spsDom += (i,j); } Is this an efficient way of doing it? Should I create a temporary array of tuples and append spsDom every ( say ) 10,000 rows? Thanks! The way you show in the snippet will expand the internal arrays of the sparse domain at every += operation. As you suggested; somehow buffering the read indices, then adding

In C++, when I need classes in 'actions.cpp' from classes.cpp I include the header, like #include <classes.h> . But trying use classes.chpl fails, is there a .h equivalent I should be using? Use is only for module names, not full file names. If your file classes.chpl does not have an explicit module enclosing its entire contents, then you would type use classes; in order to access its contents from another file. If classes.chpl is in the same directory as the file with the use statement, that should be all that is necessary to access its symbols. If classes.chpl is in a different directory,

The following code is my code for calculating pi = 3.1415... approximately using this formula: use Time; var timer = new Timer(); config const n = 10**9; var x = 0.0, s = 0.0; // timer.start(); // [1]_____ for k in 0 .. n { s = ( if k % 2 == 0 then 1.0 else -1.0 ); // (-1)^k x += s / ( 2.0 * k + 1.0 ); } // timer.stop(); // [2]_____ // writeln( "time = ", timer.elapsed() ); // [3]_____ writef( "pi (approx) = %30.20dr\n", x * 4 ); // writef( "pi (exact) = %30.20dr\n", pi ); // [4]_____ When the above code is compiled as chpl --fast test.chpl and executed as time ./a.out , then it runs with ~4

Or any similar data structure of dynamic length, which, can be cast easily to an array. The only workaround I have found is entering the array as a string and manually parsing it. config var not_array: string = '[1,2,3,4,5]' ; proc main() { // config array workaround writeln("I am string. Definitely not array ", not_array) ; // parse string not_array = not_array.replace(' ','') ; not_array = not_array.replace('[','') ; not_array = not_array.replace(']','') ; var still_not_array = not_array.split(',') ; // prepare array var dom = 0..#still_not_array.size ; var array: [dom] real ; // populate

This one is probably really stupid. How do you check the subclass of an object in Chapel? class Banana : Fruit { var color: string; } class Apple: Fruit { var poison: bool; } class Fruit { } var a = new Apple(poison=true); var b = new Banana(color="green"); // ?, kinda Java-ish, what should I do? if (type(a) == Apple.class()) { writeln("Go away doctor!"); } Though I'm asking about a subclass, I realize I don't know how to check if it's a Fruit class either. For an exact type match, you will want to write this: if (a.type == Apple) { writeln("Go away doctor!"); } To check if the type of a is a

I didn't find how the domain map maps the indices in the multi-dimensional domains to the multi-dimensional target locales. 1.) How the target locales (one dimension) is arranged in multi-dimension fashion which equals the distribution dimension to map the indexes? 2.) In documentation it states that for multi-dimension case, the computation should be done in every dimension. For the domain {1..8, 1..8} ==> dom assume dom is block-distributed over 6 target locales. Steps in mapping 1 for 1st dimension (1..8) do the computation if idx is low<=idx<=high then locid is floor (idx-low)*N / (high