Include S3 Methods for `lm` models

[moritzpschwarz]

Working on S3 methods for lm models and other S3 methods.

[moritzpschwarz]

New S3 Methods for gets package

In this branch, I have tried to add a few, in my mind useful, S3 Methods

Overview

• Turned isat and arx into S3 methods
• Added cross S3 methods i.e. gets.isat, arx.isat, and isat.arx
• Added S3 methods for seamless integration of lm models i.e. isat.lm, gets.lm, and arx.lm
• Small bugfix and robustification

Changed Files

To enable the S3 methods I have had to make a number of changes, including to:

1. the NAMESPACE where I:

• added the S3 methods at the bottom to register them as S3 methods
• added the S3 methdos in the export section (following the existing practice of exporting basically all substantial functions)

2. the gets-isat-source.R where I:

• introduce the new S3 method for isat by converting the existing isat to isat.default and then adding an isat function with a UseMethod command.
• Add a new element to the $aux list of the isat object with the name of arguments, which incorporates all arguments of each function - independent of whether they have explicitly been called or whether they are the default value and independent of which level of sys.call they represent.
• Additionally, I fixed a small bug concerning the print.searchinfo behaviour (see below).

3. the gets-base-source.R where I:

• introduce the new S3 method for arx by converting the existing arx to arx.default and then adding an arx function with a UseMethod command.
• Add a new element to the $aux list of the getsm and arx object with the name of arguments, which incorporates all arguments of each function - independent of whether they have explicitly been called or whether they are the default value and independent of which level of sys.call they represent. Note: I opted not to change anything in getsv, but this could be standardised across functions.
• within getsm and arx robustified the check regarding the user.estimator, which had been relying on call. This worked fine without the S3 methods, but with the S3 methods the call element is more difficult to deal with. The argument now relies on the new $aux$arguments information. Note: I opted not to change anything in getsv, but this could be standardised across functions.

4. in the documentation files I:
   • Added all relevent information on the S3 methods.

Added Files

I added two new files, the file gets-lm-S3.R where the code of the new S3 methods lies and additionally, I have added a test file for these new methods called test-gets-test09-S3-lm.R

Other small changes:

• In isat, I changed the logical argument that is currently supplied to the dropvar function. The dropvar function takes the logical argument silent, to which the variable print.searchinfo is supplied. print.searchinfo, however, is TRUE when more output is wanted i.e. when it is not intended to be silent. Therefore the message of dropping of variable is shown when print.searchinfo = FALSE rather than print.searchinfo = TRUE. The function therefore was changed from dropvar(mXis, tol=tol, LAPACK=LAPACK,silent=print.searchinfo) to dropvar(mXis, tol=tol, LAPACK=LAPACK,silent=!print.searchinfo)