@coldemean |

Demean each column of a matrix.

Syntax: @coldemean(m)

m: matrix

Return: matrix

Returns the matrix containing the results from subtracting the column mean from each column of m.

For each element of the output matrix :

for the mean of column where

(18.1) |

where is the number of non-missing values in the column. If there are missing values in a column, they are ignored and the number of rows is adjusted.

Examples

matrix m1 = @mnrnd(50, 4)

matrix m1d = @coldemean(m1)

demeans each column of M1 and places the results in M1D.

This operation is equivalent to

vector m1means = @cmeans(m1)

matrix m2d = m1 - @kronecker(@ones(m1.@rows), m1means.@t)

where @cmeans is used to compute the column means of M1.

Cross-references