Ary Borenszweig wrote:
Andrei Alexandrescu escribió:
I've updated my code and documentation to include series (as in math)
in the form of infinite ranges. Also series in closed form (given n
can compute the nth value without iterating) are supported as
random-access ranges.
Also Stride is provided. The Matrix container (speaking of scientific
computing with D!) will support various representational choices, most
importantly the ones endorsed by high-performance libraries. For
Matrix, Stride is an important component as I'm sure anyone who's ever
written a matrix knows.
http://ssli.ee.washington.edu/~aalexand/d/web/phobos/std_range.html
http://ssli.ee.washington.edu/~aalexand/d/web/phobos/std_algorithm.html
Back to series. Finally my dream has come true: I can define a decent
Fibonacci series clearly and efficiently in one line of code. No more
idiotic recursive function that takes exponential time to finish!
auto fib = series!("a[n-1] + a[n]")(1, 1);
// write 10 Fibonacci numbers
foreach (e; take(10, fib)) writeln(e);
That is *SO* awesome!!
Thanks! Constant-space factorial is just a line away:
auto fact = series!("a[n] * (n + 1)")(1);
foreach (e; take(10, fact)) writeln(e);
writes:
1
1
2
6
24
120
720
5040
40320
362880
And this lousy series approximating pi:
auto piapprox = series!("a[n] + (n & 1 ? 4. : -4.) / (2 * n + 3)")(4.);
foreach (e; take(200, piapprox)) writeln(e);
Very slowly convergent. :o)
Andrei
