6.3.9.6.5.1.2. statsmodels.sandbox.distributions.mv_normal.MVT.affine_transformed¶
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MVT.
affine_transformed
(shift, scale_matrix)[source]¶ return distribution of a full rank affine transform
for full rank scale_matrix only
Parameters: shift : array_like
shift of mean
scale_matrix : array_like
linear transformation matrix
Returns: mvt : instance of MVT
instance of multivariate t distribution given by affine transformation
Notes
This checks for eigvals<=0, so there are possible problems for cases with positive eigenvalues close to zero.
see: http://www.statlect.com/mcdstu1.htm
I’m not sure about general case, non-full rank transformation are not multivariate t distributed.
y = a + B x
where a is shift, B is full rank scale matrix with same dimension as sigma