Description
Please correct me if I am wrong, but it is my understanding that callingaxis_windows will return a Producer that traverses along the provided axis, not in any other axis. Therefore the associated type NdProducer::Dim should be Ix1, and the NdProducer::Item = ArrayView<'_, _, D>. Unfortunately they are both D.
I have a use-case where I need to zip some n-D data with a 1-D vector to calculate some result:
let data = array![
[1,15],
[2,14],
[3,13],
[4,12],
[5,11],
[6,10],
];
let x = array![10,20,30,40,50,60];
let mut result: Array<i32,_> = Array::zeros(data.raw_dim());
// everything except the first and last result we need to
// calculate them seperately, because there is not sufficient data
let mut inner_result = result.slice_axis_mut(Axis(0), Slice::from(1..-1));
Zip::from(inner_result.axis_iter_mut(Axis(0)))
.and(x.windows(3))
.and(data.axis_windows(Axis(0), 3))
.for_each(|y, x, data|{
// calculate some result y_n with values from data_n-1, data_n and data_n+1
// as well as x_n-1, x_n and x_n+1
todo!()
});Error
error[E0271]: type mismatch resolving `<Windows<'_, {integer}, Dim<[usize; 2]>> as IntoNdProducer>::Dim == Dim<[usize; 1]>`
--> src/interp1d.rs:679:18
|
679 | .and(data.axis_windows(Axis(0), 3))
| --- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected an array with a fixed size of 1 element, found one with 2 elements
| |
| required by a bound introduced by this call
|
= note: expected struct `Dim<[usize; 1]>`
found struct `Dim<[usize; 2]>`
note: the method call chain might not have had the expected associated types
--> src/interp1d.rs:679:23
|
662 | let data = array![
| ____________________-
663 | | [1,15],
664 | | [2,14],
665 | | [3,13],
... |
668 | | [6,10],
669 | | ];
| |_________- this expression has type `ArrayBase<OwnedRepr<{integer}>, Dim<[usize; 2]>>`
...
679 | .and(data.axis_windows(Axis(0), 3))
| ^^^^^^^^^^^^^^^^^^^^^^^^ `IntoNdProducer::Dim` is `Dim<[usize; 2]>` here
note: required by a bound in `ndarray::Zip::<(P1, P2), D>::and`
--> /home/jonas/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ndarray-0.15.6/src/zip/mod.rs:912:1
|
912 | / map_impl! {
913 | | [true P1],
914 | | [true P1 P2],
915 | | [true P1 P2 P3],
... |
918 | | [false P1 P2 P3 P4 P5 P6],
919 | | }
| |_^ required by this bound in `Zip::<(P1, P2), D>::and`
= note: this error originates in the macro `map_impl` (in Nightly builds, run with -Z macro-backtrace for more info)
I can not think of any reason why the dimension being D instead of Ix1 would be useful.
axis_iter() is essentially the same thing with the window size set to 1 and it has NdProducer::Dim = Ix1.
Actually the x in my example is not needed to produce the error, but it highlights the fact that I can not use axis_windows_mut(Axis(0), 1) (which does not exist for mut?) as a workaround.