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vec

vec(Array) -> Vector

Vectorize an array using column-major convention.

Examples

In the Julia programming language, the function vec(array) is used to vectorize an array using column-major convention.

julia> arr = [1 2 3; 4 5 6; 7 8 9]
3×3 Array{Int64,2}:
 1  2  3
 4  5  6
 7  8  9

julia> vec(arr)
9-element Array{Int64,1}:
 1
 4
 7
 2
 5
 8
 3
 6
 9

This function reshapes the array into a one-dimensional vector by stacking the columns of the array in a column-major order.

Common usage examples:

1. Vectorize a 2D array:

   julia> arr = [1 2; 3 4; 5 6];
   julia> vec(arr)
   6-element Array{Int64,1}:
   1
   3
   5
   2
   4
   6

   The vec function transforms the 2D array into a 1D vector by stacking the columns.

2. Vectorize a 3D array:

   julia> arr = [1 2 3; 4 5 6; 7 8 9] |> reshape(_, (3, 3, 1));
   julia> vec(arr)
   9-element Array{Int64,1}:
   1
   4
   7
   2
   5
   8
   3
   6
   9

   The vec function transforms the 3D array into a 1D vector by stacking the columns.

Common mistake example:

julia> arr = [1 2 3; 4 5 6];
julia> vec(arr)
ERROR: DimensionMismatch("matrix is not square: dimensions are (2, 3)")

In this example, the input array is not a square matrix, resulting in a DimensionMismatch error. Make sure the input array has appropriate dimensions for vectorization using vec.

See Also

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