polymat#

Purpose#

Returns a matrix containing the powers of the elements of x from 1 to p.

Format#

y = polymat(x, p)#
Parameters:

  • x (NxK matrix) – data

  • p (scalar) – positive integer.

Returns:

y (Nx(p*K) matrix) – contains powers of the elements of x from 1 to p. The first K columns will contain first powers, the second K columns second powers, and so on.

Remarks#

To do polynomial regression use ols:

{ vnam, m, b, stb, vc, stderr, sigma, cx, rsq, resid, dwstat } = ols(0, y, polymat(x, p));

Examples#

x = { 1, 2, 3 };

// Create matrix with powers 1 through 3
y = polymat(x, 3);
print y;

The code above produces the following output:

1.0000000   1.0000000   1.0000000
2.0000000   4.0000000   8.0000000
3.0000000   9.0000000   27.000000

Each column contains the elements of x raised to the 1st, 2nd, and 3rd powers.

Source#

polymat.src

See also

Functions polychar(), polymult(), polyroot(), polyeval()

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