Re: [math] Improving numerics in OLSMultipleLinearRegression

2008-07-12 Thread Phil Steitz
Mauro Talevi wrote: Phil, Phil Steitz wrote: I think R uses QR as described above. Comments or suggestions for other default implementations are most welcome. We should aim to provide a default implementation that is reasonably fast and provides good numerics across a broad range of design

Re: [math] Improving numerics in OLSMultipleLinearRegression

2008-06-20 Thread Mauro Talevi
Phil Steitz wrote: Perhaps it would help if we had overloaded newData methods that accept different input strategies, but ultimately they will produce a n x m double array. That way we can provide users with choice. I was thinking the same thing. The bit that is troubling me is the omega matr

Re: [math] Improving numerics in OLSMultipleLinearRegression

2008-06-20 Thread Mauro Talevi
Phil, Phil Steitz wrote: I think R uses QR as described above. Comments or suggestions for other default implementations are most welcome. We should aim to provide a default implementation that is reasonably fast and provides good numerics across a broad range of design matrices. Got aroun

Re: [math] Improving numerics in OLSMultipleLinearRegression

2008-06-15 Thread Mauro Talevi
Phil Steitz wrote: No, just X. see the references here: http://apache.markmail.org/message/3aybm5emimg5da42 I think R uses QR as described above. Comments or suggestions for other default implementations are most welcome. We should aim to provide a default implementation that is reasonably

Re: [math] Improving numerics in OLSMultipleLinearRegression

2008-06-14 Thread Phil Steitz
Mauro Talevi wrote: Phil Steitz wrote: Yes, and I would distinguish performance optimization from numerical accuracy. From my perspective, we can release a ".0" with room for performance improvement, but at least decent numerics are required. I agree that decent numerics are required. I'm

Re: [math] Improving numerics in OLSMultipleLinearRegression

2008-06-12 Thread Mauro Talevi
Phil Steitz wrote: Yes, and I would distinguish performance optimization from numerical accuracy. From my perspective, we can release a ".0" with room for performance improvement, but at least decent numerics are required. I agree that decent numerics are required. I'm still rather surpris

Re: [math] Improving numerics in OLSMultipleLinearRegression

2008-06-09 Thread Phil Steitz
Mauro Talevi wrote: Hi Phil, thanks for reviewing the multiple linear regression implementations and setting up the R/NIST data tests. I finally got around to installing R and can now run them too. Phil Steitz wrote: While clear and elegant from a matrix algebra standpoint, the "nailve" i

Re: [math] Improving numerics in OLSMultipleLinearRegression

2008-06-09 Thread Mauro Talevi
Hi Phil, thanks for reviewing the multiple linear regression implementations and setting up the R/NIST data tests. I finally got around to installing R and can now run them too. Phil Steitz wrote: While clear and elegant from a matrix algebra standpoint, the "nailve" implementation in OLSM

[math] Improving numerics in OLSMultipleLinearRegression

2008-06-08 Thread Phil Steitz
While clear and elegant from a matrix algebra standpoint, the "nailve" implementation in OLSMultipleLinearRegression has bad numerical qualities. It is well known that solving the normal equations directly does not give good numerics. I just added some tests to actually verify parameter value