point_3d_variance {synr} | R Documentation |
Calculates sample variance of points' distances in 3D space from their centroid. This function is normally only used indirectly through 'validate_get_twcv'.
point_3d_variance(point_matrix)
point_matrix |
An n-by-3 numerical matrix where each row corresponds to a single point in 3D space. |
A one-element numeric vector holding calculated variance
The variance here is taken to mean the sum of variances for each dimension/axis:
\frac{\sum_{i=1}^n (x_i-x_m)^2 + (y_i-y_m)^2 + (z-z_m)^2}{n-1}
Where X/Y/Z
represent one axis each, a_m
represents the mean
of all points' coordinates on an axis, and n
represents the total
number of points.