rust - 使用Arrayfire设置索引值

Question

我正在尝试使用自定义值修改现有Arrayfire矩阵中的值。以下是将几行和几列更改为指定值(1.0)的示例，但是我却在努力不做两件事:

改为更改要更改区域的尺寸(3x3)->(2x2)。

水平或垂直移动要更改的区域。我所做的任何更改似乎都给出了无效的索引错误。

use arrayfire::{constant, Dim4, Seq, assign_seq, print};
let a    = constant(2.0 as f32, Dim4::new(&[5, 3, 1, 1]));
let b    = constant(1.0 as f32, Dim4::new(&[3, 3, 1, 1]));
let seqs = &[Seq::new(1.0, 3.0, 1.0), Seq::default()];

print(&a);
// 2.0 2.0 2.0
// 2.0 2.0 2.0
// 2.0 2.0 2.0
// 2.0 2.0 2.0
// 2.0 2.0 2.0

let sub  = assign_seq(&a, seqs, &b);


print(&sub);
// 2.0 2.0 2.0
// 1.0 1.0 1.0
// 1.0 1.0 1.0
// 1.0 1.0 1.0
// 2.0 2.0 2.0

Answer 1

经过数天的研究，在与图书馆作者联系后，我找到了答案:

use arrayfire::{constant, Dim4, Seq, assign_seq, print};

//This is the "parent" matrix.
let a    = constant(2.0 as f32, Dim4::new(&[4, 4, 1, 1]));

//To modify a 2x2 area inside a, this must be 2x2 as well
let b    = constant(1.0 as f32, Dim4::new(&[2, 2, 1, 1]));

//Use two seq::new objects, NOTE that matrices are column major.
let seqs = &[Seq::new(1.0, 1.0, 1.0), Seq::new(1.0, 1.0, 1.0)];

Arrayfire 3.7.1还引入了一种新的优雅语法:

let mut a = arrayfire::constant(2.0 as f32, arrayfire::dim4!(4, 4));
let b = arrayfire::constant(1.0 as f32, arrayfire::dim4!(2,2));

arrayfire::print(&a);
arrayfire::eval!(a[1:1:1, 1:1:1] = b);
arrayfire::print(&a);