pub fn gda_query() -> (Vec<Axis>, ZipTerm)Expand description
The covariance step of Spatial’s GDA regression app (pir/regression/GDA.scala), transcribed: over the arrays
y (at the row), x (row-major), mu1 and mu0 (at the column), read in that order, the row term
x(rr, cc) - mux(y(rr) == 1, mu1(cc), mu0(cc)), each row’s outer product with itself summed into sigma.