Matvec Users’ Guide

Chapter 2
Working on Objects
Matvec is object-oriented. Almost every piece in Matvec system is an object. All objects in Matvec can
be classified into nine classes: Scalar, Vector, Matrix, SparseMatrix, String, Data, Model, FileStream, and
StatDist.
It should always keep in mind that you’re using an object-oriented language. Thus, to play with Matvec
you have to create your own objects at the very beginning.
2.1 Special Object: this
A very special object built in Matvec is this. It is the object of the current working session. All of the
parameters, properties pertaining to the current working session can be changed through this special object.
For C++ programmer, keyword this is an old friend
If you simply type this, it will display the names of the user-defined variables and functions.
this.clear(a,b,...) deletes the named objects from the current Matvec session immediately. The memory
associated with the objects are freed. this.clear() deletes all objects (but not the builtins’) and all intermediate
temporary files (but not ones created from the other matvec sessions) from the matvec trash can. The
return value is the number of objects that have been successfully deleted.
this.parameter( "OUTPUT_PRECISION", k) sets the output precision for the current Matvec working session
to k. The default value is 6. this.parameter( "OUTPUT_PRECISION") returns the output precision in the
current Matvec working session. Note that “precision” is defined to be the number of significant digits in
output.
this.parameter( "WARNING", k) sets the warning flag for the current working session to k, which can be
either 1 or 0. The default value is 1. this.parameter( "WARNING") returns the value of the warning flag in
the current working session.
this.parameter( "EPSILON", x) sets the epsilon value for the current Matvec working session to x.
The default value is 1.0e-14. Matvec users are strongly discouraged to change the default epsilon value.
this.parameter( "EPSILON") returns the epsilon value in the current Matvec working session.
this.parameter( "OUTPUT_LINE_WIDTH", k) sets the line width of output for the current Matvec working
session to k. The default value is 80. this.parameter( "OUTPUT_LINE_WIDTH") returns the line width of
output in the current Matvec working session.
this.parameter( "INPUT_LINE_WIDTH", k) sets the line (record) width for input in the current Matvec
working session to k. The default value is 1024. this.parameter( "INPUT\_LINE\_WIDTH") returns the line
(record) width for input in the current Matvec working session.
this.parameter( "MAX_ERRORS", k) sets the maxmum number of errors allowed for the current Matvec
working session to k. The default value 15. this.parameter( "MAX_ERRORS") returns the maxmum number of
errors allowed for the current Matvec working session.
For example,
> this.parameter("OUTPUT_PRECISION")
9