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Binary operation for ArrayView #237
Description
I'm confusing errors arising around +.
let dist = Range::new(0, 1);
let a = Array::<f64, _>::random((5, 5));
let x0 = Array::<f64, _>::random(5);
let xs: Vec<_> = a.axis_iter(Axis(0)).map(|x| x + &x0);I expect that x + &x0 produces new array since document says
&A @ &A which produces a new Array
But it produces an error:
error[E0369]: binary operation `+` cannot be applied to type `ndarray::ArrayBase<ndarray::ViewRepr<&f64>, usize>`
After struggling, I find it works when I rewrite the last line as following:
let xs: Vec<_> = a.axis_iter(Axis(0)).map(|x| x.to_owned() + &x0);I hope the first my code works. Is there any technical problem to implement Add for ArrayView?
Activity
bluss commentedon Nov 15, 2016
xinx + &x0is an array view, which is an "A", not an "&A". So&x + &x0should work.termoshtt commentedon Nov 15, 2016
Oh...
I now understand my mistake and what document says.
The above error message means
ArrayViewcannot be consumed. It is hard to read :<Thanks for your help!
bluss commentedon Nov 15, 2016
It's a bit unfortunate that one needs to pass
&ArrayViewin many places where just passing a view by value should be enough. It's partly due to missing support for custom view types in Rust. Feel free to report any issues you find with ndarray.