COMMAND(1)

NAME
ttest - build and test trees and report statistics

SYNOPSIS
ttest [options] stem size

DESCRIPTION

ttest is a csh script used to control the running of experiments on trees. stem should be a simple file name and not a path name. A sequence of training/tests pairs are formed using encsmpl, various trees are built using mktree with different options, and statistics are collected in separate report files or output to stdio using tclass. A final summary report is output to stdio using lstat. stem is the data set stem to use, size is the size of training sets to generate. Control of which tree generation and prune combinations to use is specified by the -T and -s options. A typical command sequence to concurrently run MDL-like trials on the "hypo" data set might be to use preset styles like:

    ttest -v -s mml hypo 500

or with more fine control over options by using:

    ttest -v -T "-tPmml -Pchoices -Aclasses,1" \
          "-B" "mdl" -c -sblv hypo 500

See the description of the -T option, below, to interpret this. With this above command, ttest will first output the following summary,

    Running trials:
         tgen -tPmml -Pchoices -Aclasses,1 hypo... ; tprune -B
    Redirecting results to:
         hypo.trial.500mdl

and then proceed to run the trials indicated using files hypo.bld, hypo.tree.1, etc. In this case, for each tree generated, tclass is run using options "-sblv" and the output appended to the respective report files. Selection of training/test data pairs is controlled by the -C and -V options. This allows cross validation, random generation of partitions according to a list of seeds, or cross validation on random partitions.

OPTIONS

-c clopts
    Pass these options to tclass when generating statistics on individual trees. The default is "-svlb", or is modified by the preset styles.

-C folds
    When used alone, this option cancels the use of a seedfile (see the -V option). Instead training/test data set pairs are generated from the full data set in cross-validation style with folds number of folds. If this option is followed by a -V or -v option, then samples are first selected (using the supplied seeds) and cross-validation is done with each of these samples (instead of the full data set), by sub-partitioning them in turn into a number of folds. This then returns a cross-validation estimate (with variances) of the statistics produced by running ttest without the -C option. (i.e. the report file produced with the -C option will be an estimate with variances of the statistics determined on the test sample without the -C option.)

-d  Normally, statistics generated are appended to the existing report files. This option says to delete all report files at the very beginning so statistics collected represent those generated in just this run of ttest.

-k  On abnormal exit, by default mkclean will be called, this option cancels this default.

-l llopts
    Pass these options to lstat when generating the final summary report. The default is "-f 2 -v 1,2,3".

-L  Use logical (see use of "L" in encsmpl(1)) style sampling.

-m datasize
    Passed onto mktree.

-O  Output all results to stdio. With this option, the filename modifier to the -T option is assumed not to exist.

-P prune pname
    Prune the tree generated once more using the pruning command "tprune prune stem..." and output the results to an additional results file "stem.trial.sizepname". This way, the single tree generated can be pruned multiple times to yield multiple results files.

-Q  Print a banner at the beginning giving the command and the date. Should be first option on the command line. Shorter version than -v option to use to record runs in an audit trial.

-s stylename
    Rather like -T but for a preset style. The styles are the same as for mktree, and multiple styles overlay, still producing only one tree each sample.

-t cputime
    Passed onto mktree.

-T trial prune name
    Build a tree using the command "mktree -o trial -p prune" and append the statistics gathered from tclass to the file "stem.trial.sizename". tclass is ran with the -b option plus other defaults. The name argument is assumed not to exist if output is to stdio. The -T option can occur multiple times and the options will be overlayed, still producing only one tree each sample.

-v  The verbose option. Print out a few more details during operation.

-V seeds
    One trial is run for each train/test pair of the data set. Seeds and appropriate sampling options are passed one at a time to encsmpl to generate these different train test pairs. Either the argument seeds is a file containing white space-separated integers to use as seeds (the default is "../seeds"), or seeds is a comma delimited list of integer seeds to use.

-Z  Leave the ".enc" files compressed during use. For really large encoded data files.

SEE ALSO
tclass(1), tgen(1), mktree(1),