FreeMat: RESHAPE Reshape An Array

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RESHAPE Reshape An Array

Section: Array Generation and Manipulations

# Usage

Reshapes an array from one size to another. Two seperate syntaxes are possible. The first syntax specifies the array dimensions as a sequence of scalar dimensions:

       y = reshape(x,d1,d2,...,dn).

The resulting array has the given dimensions, and is filled with the contents of `x`. The type of `y` is the same as `x`.

As a special case, you can specify exactly one of the dimensions as an empty matrix `[]`, in which case FreeMat will compute the size required in that dimension to make the reshape work. The syntax for this version is

       y = reshape(x,d1,...,da,[],db,...,dn)

The second syntax specifies the array dimensions as a vector, where each element in the vector specifies a dimension length:

       y = reshape(x,[d1,d2,...,dn]).

This syntax is more convenient for calling `reshape` using a variable for the argument. The `reshape` function requires that the length of `x` equal the product of the `di` values. Note that arrays are stored in column format, which means that elements in `x` are transferred to the new array `y` starting with the first column first element, then proceeding to the last element of the first column, then the first element of the second column, etc.

# Example

Here are several examples of the use of `reshape` applied to various arrays. The first example reshapes a row vector into a matrix.

    --> a = uint8(1:6)

    a =
     1 2 3 4 5 6

    --> reshape(a,2,3)

    ans =
     1 3 5
     2 4 6

The second example reshapes a longer row vector into a volume with two planes.

    --> a = uint8(1:12)

    a =
      1  2  3  4  5  6  7  8  9 10 11 12

    --> reshape(a,[2,3,2])

    ans =

    (:,:,1) =
      1  3  5
      2  4  6

    (:,:,2) =
      7  9 11
      8 10 12

The third example reshapes a matrix into another matrix.

    --> a = [1,6,7;3,4,2]

    a =
     1 6 7
     3 4 2

    --> reshape(a,3,2)

    ans =
     1 4
     3 7
     6 2