Contents - Index


Introduction

This file gives technical information about all the routines contained within UCINET.  

The manual assumes that users have certain rudimentary knowledge of the Windows operating system and of network terminology. Elementary information on UCINET is available in the accompanying users guide.

Each routine is documented in a standard way.  This should help the user to understand some of the non-standard routines once documentation for which they are familiar has been thoroughly digested.


Command Format

Each routine is documented using the following keywords:  MENU, PURPOSE, PESCRIPTION, PARAMETERS, LOG FILE, COMMENTS, and REFERENCES.  The details of these are as follows:

MENU This gives the exact position of the routine within the UCINET menu system. For example NETWORK>SUBGROUPS>K-PLEX can be found by first selecting NETWORK on the top level of the menu and then from the pull down submenu selecting SUBGROUPS and then finally from this submenu selecting K-PLEX.  The selection of all the options in the MENU list followed by a mouse click will begin execution of the routine.


PURPOSE This gives a brief one or two line description of the routine.


DESCRIPTION Gives a fuller account of what the routine does.  This description will include a brief definition of some of the concepts required to understand the technique and an outline of the algorithms employed.  It should contain sufficient information for a user to fully comprehend the action of the routine.  An effort has been made to make the descriptions succinct.  Users should read descriptions carefully if they are unfamiliar with the action of a particular algorithm.

PARAMETERS This gives a complete list of what information must be supplied by the user in order to run a routine.  It contains a list of all the information requested on the forms when a routine is executed.  This list is indented in such a way as to make it clear what exactly appears on the forms.

For each entry on the form the manual gives the defaults provided by UCINET.  This can be useful in trying to locate files that have been created by the software, or when re-running a particular routine with different parameters.

In addition the manual gives additional information (to the help line on the form) about how to complete each entry on the form.

If the routine requires a dataset (which most usually do) then the manual specifies precisely which type of data can be analyzed.  These are as follows:

Graph - an nn symmetric binary adjacency matrix.

Digraph - an nn not necessarily symmetric binary adjacency matrix.

Valued graph - an nn matrix.  The entries are usually reals, sometimes there are restrictions on the values to integers or the matrix to symmetric.
 
Square matrix - an nn matrix.  The entries are usually reals, sometimes there are restrictions on the values to integers or probabilities. Obviously valued graph and square matrix are the same data type, it is just convention which dictates usage.

Matrix - an nm matrix. The entries are usually reals. These can be restricted to binary or integer.

Each data type is contained within the next.  So, for example, any routine that accepts valued graphs will run on digraphs or graphs.

Some routines contain options which will run on different data types.  In this case the data type given in the manual is the most general.  Certain options dictated by the parameters may not run with this data type.  It should be apparent from the manual which data types will be applicable for the selected parameters.

Routines which take specific action on multirelational data have this indicated in the data type specification.  For example, the routine specified by

     TRANSFORM>SEMIGROUP

has as its data type Digraph.Multirelational.  This indicates that this routine acts on multirelational data in a particular way.  If this data type is not included and a multirelational data set is submitted for analysis then UCINET will perform the analysis on each relation separately, if possible.  In some cases such an action would not make network sense, and in other cases it is simply not technically possible to do this.  In these cases the routine only acts on the first relation.


LOG FILE The LOG FILE contains output generated by each routine.  The contents of the file are displayed on the screen and the user can browse, edit, save or print it.  For each routine a comprehensive account of the contents of the file is given.


TIMING The timing gives the order of the routine related to the longest dimension of the data matrix, which is called N.  Care should be taken on the interpretation of this value since it only gives the order of the polynomial (if one exists) which dictates the time.  Hence a time O(N^3) means that for sufficiently large N the time to execute will increase at the rate of N^3.  It is quite possible for the user to increase N for an O(N^3) routine by a factor of 2 say, and the execution time to increase by 20-fold instead of the expected 8-fold increase.  This would be because N was not sufficiently large for the highest order to dominate.  Equally well it cannot be used to compare two different routines.

Whilst caution is wise for a strict interpretation, it will be true that for O(N^3) routine doubling the size of N will probably cause the execution time to increase by approximately a factor of 8.  Timings which are exponential mean that the user should be aware that small increases in N may cause very large increases in execution time.


COMMENTS Additional comments which may be of help to the user are given in this section.


REFERENCE A 'sample' of useful references which should enable the interested user to gain more information.