FreeMat: DOTPOWER Element-wise Power Operator

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DOTPOWER Element-wise Power Operator

Section: Mathematical Operators

# Usage

Raises one numerical array to another array (elementwise). There are three operators all with the same general syntax:

      y = a .^ b

The result `y` depends on which of the following three situations applies to the arguments `a` and `b`:

1. `a` is a scalar, `b` is an arbitrary `n`-dimensional numerical array, in which case the output is `a` raised to the power of each element of `b`, and the output is the same size as `b`.
2. `a` is an `n`-dimensional numerical array, and `b` is a scalar, then the output is the same size as `a`, and is defined by each element of `a` raised to the power `b`.
3. `a` and `b` are both `n`-dimensional numerical arrays of the same size. In this case, each element of the output is the corresponding element of `a` raised to the power defined by the corresponding element of `b`.

The rules for manipulating types has changed in FreeMat 4.0. See `typerules` for more details.

# Internals

There are three formulae for this operator. For the first form

and the second form

and in the third form

# Examples

We demonstrate the three forms of the dot-power operator using some simple examples. First, the case of a scalar raised to a series of values.

    --> a = 2

    a =
     2

    --> b = 1:4

    b =
     1 2 3 4

    --> c = a.^b

    c =
      2  4  8 16

The second case shows a vector raised to a scalar.

    --> c = b.^a

    c =
      1  4  9 16

The third case shows the most general use of the dot-power operator.

    --> A = [1,2;3,2]

    A =
     1 2
     3 2

    --> B = [2,1.5;0.5,0.6]

    B =
        2.0000    1.5000
        0.5000    0.6000

    --> C = A.^B

    C =
        1.0000    2.8284
        1.7321    1.5157