components_read.daphne

// Connected components.

// Arguments:
// - f ... filename of the adjacency matrix (provide as `--args f=\"foo.csv\"`)

t0 = now();

// Read adjacency matrix.
G = readMatrix($f);

// Initialization.
// TODO Don't forget to set this back to something high (e.g. 1000) later.
maxi = 5;
c = seq(1.0, as.f64(nrow(G)), 1.0); // init w/ vertex IDs
diff = inf;
iter = 1;

t1 = now();

// Iterative computation of connected components (decisive part).
while(as.si64(diff > 0.0) && iter <= maxi) {
    ti0 = now();

    u = max(aggMax(G * t(c), 0), c);
    diff = sum(u != c);
    c = u;

    ti1 = now();
    print("iteration ", 0, 1);
    print(iter, 0, 1);
    print(" took [ns]: ", 0, 1);
    print(ti1 - ti0);

    iter = iter + 1;
}

t2 = now();

// Print elapsed times in nano seconds.
print(t1 - t0); // initialization
print(t2 - t1); // core algorithm
// Note that, for distributed execution, (t2 - t1) includes reading the input
// files due to some reordering done by the compiler.

// Result output.
print(c);