MATLAB: Raise a scalar to a descending series of powers in an array

Question

I'm trying to compute a series of powers of a scalar.

This seems to work but the result is not what I expected:

0.8^1:3

ans =

0.8000 1.8000 2.8000

I expected:

ans =

0.8000 0.6400 0.5120

(It looks like it is returning 0.8:3)

This therfore doesn't work either:

0.8^3:-1:1

ans =

1×0 empty double row vector

Neither does this

0.8^(3:-1:1)

Error using ^ (line 51)

Incorrect dimensions for raising a matrix to a power. Check that the matrix is square and the power is a scalar. To perform elementwise matrix powers, use '.^'.

Neither of these work

0.8^[3 2 1]
0.8^[1 2 3]

Error using ^ (line 51)

Incorrect dimensions for raising a matrix to a power. Check that the matrix is square and the power is a scalar. To perform elementwise matrix powers, use '.^'.

So, how do I compute the scalar to the power of a series of descending values?

Answer 1

Here is the correct answer I think. Element-wise operation:

0.8.^(3:-1:1)