[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

From |
Richard Williams <Richard.A.Williams.5@ND.edu> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Nonlinear regression and constraints |

Date |
Wed, 29 Jun 2005 00:26:03 -0500 |

At 09:04 PM 6/28/2005 -0700, Daniel Schneider wrote:

Even if -nl- allowed the constraints option, I don't think these would be legal constraints; as far as I know, you can't use something like >=, you can only use =.constraint define 1 X1MX1SQDIVX3 >= 0 constraint define 2 X2SQMX2DIVX3 >= 0 constraint define 3 X1MX1SQDIVX3 <= 1 constraint define 4 X2SQMX2DIVX3 <= 1 Unfortunately, constraints() seems not to work with -nl-? Is there any other way to to do the constraints with -nl-?

Also, my impression is that -nl- doesn't need the constraints option because constraints can be specified using the -nl- command itself.

I'd be curious to know if there is some direct way to specify a range of values for the constraint, like you want; as far as I know, there always has to be some sort of equality statement.

Is there some way to transform the equation, so that, say, you wind up taking the inverse logit of the parameters of the transformed equation to get back to the parameters of the original equation? The inverse logit of any number will always range between 0 and 1. You'll see programs do little tricks like estimate the log of a parameter when the parameter itself needs to be positive.

-------------------------------------------

Richard Williams, Notre Dame Dept of Sociology

OFFICE: (574)631-6668, (574)631-6463

FAX: (574)288-4373

HOME: (574)289-5227

EMAIL: Richard.A.Williams.5@ND.Edu

WWW (personal): http://www.nd.edu/~rwilliam

WWW (department): http://www.nd.edu/~soc

*

* For searches and help try:

* http://www.stata.com/support/faqs/res/findit.html

* http://www.stata.com/support/statalist/faq

* http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**RE: st: Nonlinear regression and constraints***From:*"Daniel Schneider" <daniel.schneider@stanford.edu>

**References**:**st: Nonlinear regression and constraints***From:*"Daniel Schneider" <daniel.schneider@stanford.edu>

- Prev by Date:
**Re: st: re: constraints** - Next by Date:
**RE: st: Nonlinear regression and constraints** - Previous by thread:
**st: Nonlinear regression and constraints** - Next by thread:
**RE: st: Nonlinear regression and constraints** - Index(es):

© Copyright 1996–2023 StataCorp LLC | Terms of use | Privacy | Contact us | What's new | Site index |