.-
help for ^gpfobl^
by Herve M. CACI, March 2003
.-

Rotation after Exploratory factor analysis / Principal components analysis
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     ^gpfobl^ <matname> [, <rotation(#)> Factors(#)]

Description
-----------

This is the translation into Stata programming language of the programs
that appear in the paper:

Gradient Projection Algorithms for Arbitrary Rotation Criteria in
Factor Analysis

by Coen A. Bernaards & Robert I. Jennrich
   (http://www.stat.ucla.edu/research)

If this command is used after ^factor^, you have to get the matrix of
unrotated loadings. That is,

.matrix A=get(Ld)

.gpfobl A, oblimin(.50)

By default the number of factors is the number of columns of the inputted
matrix. However, the user can choose to rotate a lower number of factors.

.matrix A=get(Ld)

.oblimin A,f(3)

Available oblique rotation criteria are:

1. OBLIMIN(gamma): by default, gamma==0.50. If the user specifies gamma==0 then
   the rotation is QUARTIMIN, and if the user specifies gamma==1 then the
   rotation is COVARIMIN.

2. OBLIMAX: no parameter needed.

3. IPS: Bentler's Invariant Pattern Simplicity (no parameter needed).

4. CFerguson(kappa): this is in fact a family of rotations.
        - QUARTIMAX if kappa==0
        - VARIMAX if kappa==1/p
        - EQUAMAX if kappa==k/(2*p)
        - PARSIMAX if kappa==(k-1)/(p+k-2)
        - Factor parsimony if kappa==1
   where k is the number of the number of factors
     and p is the number of variables

5. GEOMIN(epsilon): by default epsilon==0.01.
