Matrix module

Collection of different utility Matrices

@author: jdiedrichsen

matrix.centering(size)

generates a centering matrix

Parameters:

size (int) – size of the center matrix

Returns:

centering_matrix (numpy.ndarray) – size * size

matrix.indicator(index_vector, positive=False)

Indicator matrix with one column per unique element in vector

Parameters:
  • index_vector (numpy.ndarray) – n_row vector to code - discrete values (one dimensional)

  • positive (bool) – should the function ignore zero negative entries in the index_vector? Default: false

Returns:

indicator_matrix (numpy.ndarray) – nrow x nconditions indicator matrix

matrix.pairwise_contrast(index_vector)

Contrast matrix with one row per unqiue pairwise contrast

Parameters:

index_vector (numpy.ndarray) – n_row vector to code discrete values (one dimensional)

Returns:

contrast matrix (numpy.ndarray) – n_values * (n_values-1)/2 x n_row