frites.stats.cluster_threshold#

frites.stats.cluster_threshold(x, x_p, alpha=0.05, tail=1, tfce=False, n_steps=100, h_power=2, e_power=0.5)[source]#

Threshold detection for cluster-based inferencse.

Parameters
xnumpy:array_like

Array of true effect size

x_pnumpy:array_like

Array of permutations

alphapython:float | .05

Thresholding permutation distribution. If alpha is 0.05 it means that the threshold is going to be the 95th percentile

tail{-1, 0, 1}

Type of comparison. Use -1 for the lower part of the distribution, 1 for the higher part and 0 for both

tfcebool | python:False

Use Threshold Free Cluster Enhancement. Use either :

  • True to specify that TFCE have to be used. In that case, the start and integration step are automatically inferred

  • A dict that contains a ‘start’ and a ‘step’ key to manually set TFCE parameters. Could also use ‘e_power’ and ‘h_power’ entries

  • A dict that is only there to set TFCE parameters n_steps, e_power and h_power but using the automatic starting and integration step

n_stepspython:int | 100

Number of integration steps between the start and stoping values for the TFCE

h_powerpython:float | 2

Default H exponent of the TFCE

e_powerpython:float | .5

Default E exponent of the TFCE

Returns
thresholdpython:float, python:dict

The cluster threshold. For the TFCE, this output a is dictionary with a ‘start’ and a ‘step’ keys (MNE convention)