LFD Book Forum Related to Legendre polynomials
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#1
06-11-2013, 07:29 AM
 skwong Member Join Date: Apr 2013 Location: Hong Kong Posts: 13
Related to Legendre polynomials

In lect 12, we learn the regularization for a nonlinear transformation which is
composed of Legendre polynomials. But then in hw6, Q2 to Q6,
The nonlinear transform doesn't talk anything about Legendre polynomials.

Does it mean, Legendre polynomials is used in deriving the theory,
and any function, including the in hw6, can actually be
expressed in terms of Legendre polynomials ? Further, does it only hold true
for the range -1 to 1 ?
#2
06-11-2013, 12:20 PM
 yaser Caltech Join Date: Aug 2009 Location: Pasadena, California, USA Posts: 1,478
Re: Related to Legendre polynomials

Quote:
 Originally Posted by skwong In lect 12, we learn the regularization for a nonlinear transformation which is composed of Legendre polynomials. But then in hw6, Q2 to Q6, The nonlinear transform doesn't talk anything about Legendre polynomials. Does it mean, Legendre polynomials is used in deriving the theory, and any function, including the in hw6, can actually be expressed in terms of Legendre polynomials ? Further, does it only hold true for the range -1 to 1 ?
Any polynomial, including the one in HW 6, can be expressed in terms Legendre polynomials. The polynomial can be defined outside the range but the orthognality of Legendre polynomials is within .
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#3
06-11-2013, 06:58 PM
 skwong Member Join Date: Apr 2013 Location: Hong Kong Posts: 13
Re: Related to Legendre polynomials

Thank you very much for the prompt reply. Does it mean that if we want to use
this regulariser, then we need to normalise the input data to range -1 to 1 ?
#4
06-11-2013, 07:36 PM
 yaser Caltech Join Date: Aug 2009 Location: Pasadena, California, USA Posts: 1,478
Re: Related to Legendre polynomials

Quote:
 Originally Posted by skwong Thank you very much for the prompt reply. Does it mean that if we want to use this regulariser, then we need to normalise the input data to range -1 to 1 ?
The regularizer can be used for any domain. It just has a nice interpretation in the domain because of the properties of Legendre polynomials in that domain.
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