st: New versions of -polyspline- and -bspline- on SSC

["Roger B. Newson" <r.newson@imperial.ac.uk>]

Thanks as always to Kit Baum, new versions of the -polyspline- and 
-bspline- packages are now available for download from SSC. In Stata, 
use the -ssc- command to do this, or -adoupdate- if you already have old 
versions of these packages.

The packages -polyspline- and -bspline- are described as below on my 
website. The package -polyspline- is an easy-to-use front-end for 
-bspline-, and requires -bspline- to be installed in order to work.

The new -polyspline- will now still work if the user specifies a 
-power()- option too high for a polynomial of that degree to be 
specified for the available reference points on the X-axis, because it 
then revises the power downwards to be one less than the number of 
reference points. And -polyspline- now also informs the user how many 
reference splines have been generated, and what treir degree is.

The new -bspline- fixes a bug which caused the returned result 
-r(nspline)- to be erroneous (one less than the true number of generated 
reference splines) when a -base()- option was specified. This is now fixed.

Best wishes

Roger

--
Roger B Newson BSc MSc DPhil
Lecturer in Medical Statistics
Respiratory Epidemiology, Occupational Medicine
and Public Health Group
National Heart and Lung Institute
Imperial College London
Royal Brompton Campus
Room 33, Emmanuel Kaye Building
1B Manresa Road
London SW3 6LR
UNITED KINGDOM
Tel: +44 (0)20 7352 8121 ext 3381
Fax: +44 (0)20 7351 8322
Email: r.newson@imperial.ac.uk
Web page: http://www.imperial.ac.uk/nhli/r.newson/
Departmental Web page:
http://www1.imperial.ac.uk/medicine/about/divisions/nhli/respiration/popgenetics/reph/

Opinions expressed are those of the author, not of the institution.

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package polyspline from http://www.imperial.ac.uk/nhli/r.newson/stata10
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TITLE
      polyspline: Generate sensible bases for polynomials and other splines

DESCRIPTION/AUTHOR(S)
      The polyspline package inputs an X-variable and a list of
      reference points on the X-axis, and generates a basis of
      reference splines (one per reference point) for a polynomial
      or other unrestricted spline.  This basis can be included in
      the list of covariates of a regression model.  The estimated
      parameters will then be values of the spline at the reference
      points, or differences between values of the spline at the
      reference points and the value of the spline at a base
      reference point.  polyspline is an easy-to-use front end for
      the SSC package bspline, which must be installed for
      polyspline to work.

      Author: Roger Newson
      Distribution-date: 06 January 2014
      Stata-version: 10


INSTALLATION FILES                                  (click here to install)
      polyspline.ado
      polyspline.sthlp
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(click here to return to the previous screen)


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package bspline from http://www.imperial.ac.uk/nhli/r.newson/stata10
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TITLE
      bspline: Create a basis of B-splines or reference splines

DESCRIPTION/AUTHOR(S)
      The bspline package contains 3 commands, bspline, frencurv
      and flexcurv.  bspline generates a basis of B-splines in the
      X-variate based on a list of knots, for use in the design
      matrix of a regression model.  frencurv generates a basis of
      reference splines, for use in the design matrix of a
      regression model, with the property that the parameters
      fitted will be values of the spline at a list of reference
      points.  flexcurv is an easy-to-use version of frencurv, and
      generates reference splines with regularly-spaced knots, or
      with knots interpolated between the reference points.
      frencurv and flexcurv have the additional option of
      generating an incomplete basis of reference splines, which
      can be completed by the addition of the standard constant
      variable used in regression models.  The splines are either
      given the names in the newvarlist (if present), or (more
      usually) generated as a list of numbered variables, prefixed
      by the generate() option.  Usually (but not always), the
      regression command is called using the noconst option.

      Author: Roger Newson
      Distribution-date: 06 January 2014
      Stata-version: 10


INSTALLATION FILES                                  (click here to install)
      bspline.ado
      bspline.sthlp
      frencurv.ado
      frencurv.sthlp
      flexcurv.ado
      flexcurv.sthlp

ANCILLARY FILES                                     (click here to get)
      bspline.pdf
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(click here to return to the previous screen)
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