On Thursday, 7 September 2017 at 09:40:40 UTC, Ilya Yaroshenko
wrote:
For example, lets takes `transposed` function. It does not
transpose the date. Instead, it swap dimensions.
Assume you have a canonical matrix with _lengths = [3, 4]. So
its strides are [4]. Now we want to swap dimensions, but to do
it we need to swap both lengths and strides. So first we need
to convert a slice to universal, so it will have both strides
we want to swap: [4, 1]. Transposed slice will have _lengths =
[4, 3] and _strides = [1, 4].
Best Regards,
Ilya
I think what's missing from the documentation is a clear
explanation of how the strides determine how the iterator moves.
Even something like below (assuming I have the math right) would
be an improvement, though I'm sure there is a clearer way to
express the concept.
auto x = iota(3, 4).universal;
assert(x.strides == [4, 1]);
assert(x[2, 3] == 6); //(2 - 1) * 4 + (3 - 1) * 1
auto y = x.transposed;
assert(y.strides == [1, 4]);
assert(y[2, 3] == 9); //(2 - 1) * 1 + (3 - 1) * 4
