On Saturday, 19 September 2015 at 10:45:22 UTC, Russel Winder
wrote:
Calling D from Python. I have two functions in D, compiled to a
shared object on Linux using LDC (but I get same problem using
DMD).
The sequential code:
extern(C)
double sequential(const int n, const double delta) {
Runtime.initialize();
const pi = 4.0 * delta * reduce!(
(double t, int i){ immutable x = (i - 0.5) * delta;
return t + 1.0 / (1.0 + x * x); })(
0.0, iota(1, n + 1));
Runtime.terminate();
return pi;
}
works entirely fine. However the "parallel" code:
extern(C)
double parallel(const int n, const double delta) {
Runtime.initialize();
const pi = 4.0 * delta * taskPool.reduce!"a + b"(
map!((int i){ immutable x = (i - 0.5) * delta; return
1.0 / (1.0 + x * x); })(iota(1, n + 1)));
Runtime.terminate();
return pi;
}
causes an immediate segfault (with LDC and DMD. I am assuming
that the problem is the lack of initialization of the
std.parallelism module and hence the use of taskPool is causing
a problem. I am betting I am missing something very simple
about module initialization, and that this is not actually a
bug.
Anyone any proposals?
Btw have you looked at Colvin's prettypyd ? It's a nicer way to
wrap things. Just @pdef!() before functions, aggregates and
fields to wrap them.
For demos, I should also think that showing Python code in one
Jupyter cell calling D code in another is a pretty nice way to
show interop. Just need to install the pyd Magic. Your D code
can import dub libraries too.
