在朱莉娅中使用理解创建矩阵

Question

我想创建一个对角线是 1/2 的幂的对角矩阵。我知道我可以做到：

A = Diagonal(1, 1/2, 1/2^2, ..., 1/2^10)

我想知道是否有一种方法可以使用理解来做到这一点，就像这样：

A = Diagonal((1/2)^x for x=[0:10])

Answer 1

Diagonal constructor takes the diagonal as a vector for input, so just use a regular vector comprehension:

julia> using LinearAlgebra

julia> Diagonal([1/2^i for i in 0:4])
5×5 Diagonal{Float64, Vector{Float64}}:
 1.0   ⋅    ⋅     ⋅      ⋅ 
  ⋅   0.5   ⋅     ⋅      ⋅ 
  ⋅    ⋅   0.25   ⋅      ⋅ 
  ⋅    ⋅    ⋅    0.125   ⋅ 
  ⋅    ⋅    ⋅     ⋅     0.0625

在朱莉娅中使用理解创建矩阵

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