[R] Scaling Matrix in qda() function in MASS package

[Souradeep Chattapadhyay]

Hello,
           I am Souradeep Chattopadhyay and I am a graduate student at Iowa
State University Department of Statistics.

Can anyone please explain the mathematical formulation behind the scaling
matrix returned by the qda function in MASS package. I want to understand
how this scaling matrix is derived from the inputs given to the qda
function.

Example Code

The following example is using the banknote data in the MCLUST package.

*Code*

require(MASS)
require(mclust)
data(banknote)
quad<-qda(banknote[,-1], grouping=banknote$Status, method="mle")
quad$scaling


Scaling matrix returned by qda for this data is

, , counterfeit

                1                    2              3
 4                     5          6
Length   2.853988  1.069414 -0.05279774  0.750531723 -0.2053821  0.6986088
Left        0.000000 -4.208108 -3.04707132 -0.026804815 -0.8644062
-1.1088947
Right      0.000000  0.000000  4.27383763  0.003205759  0.3313675  1.3865888
Bottom   0.000000  0.000000  0.00000000  0.917596063 -0.8707772  0.7274894
Top         0.000000  0.000000  0.00000000  0.000000000 -2.2041415
 0.6956074
Diagonal 0.000000  0.000000  0.00000000  0.000000000  0.0000000-2.1879157

, , genuine

                1                     2               3                4
              5               6
Length  2.592911 -1.169164  0.6105339 -0.3614352 -0.2520496 -0.5281743
Left       0.000000  3.027882  2.2392994 -0.2842368 -1.2092325  0.6927868
Right    0.000000  0.000000 -3.8684746 -0.3972362 -0.4177546 -0.1062555
Bottom 0.000000  0.000000  0.0000000  1.6376150  1.7274240  0.3969998
Top       0.000000  0.000000  0.0000000  0.0000000  2.3022115  0.6318543
Diagonal 0.000000  0.000000  0.0000000  0.0000000  0.0000000  2.4516680



Thanks and Regards

Souradeep

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