Use the type command to determine if a package is implemented as a module or as a table.

type(packagename, `module`);

type(packagename, table);

For example,

type(networks, '`module`');

type(VectorCalculus, '`module`');

Once you have determined how the package has been implemented, follow the instructions in one of the following sections.

Packages Implemented as Modules

Packages Implemented as Tables

To use a top-level command after its name has been rebound to a package-level command, use the colon-dash syntax (:-commandname).

The following example intentionally employs an error message to illustrate which command level is used.

diff( );

Error, invalid input: diff expects 2 or more arguments, but received 0

Note: The message refers to the top-level diff command.

Now invoke the VectorCalculus package.

with(VectorCalculus);

The VectorCalculus package contains a diff command. For differences between the two commands, see diff and VectorCalculus[diff].

Enter the diff(); command again.

diff();

Error, invalid input: VectorCalculus:-diff uses a 1st argument, f, which is missing

The message now indicates that the error is generated by the VectorCalculus package-level command and not the top-level diff command.

To use the top-level diff command, use the :- syntax.

:-diff();

Error, invalid input: diff expects 2 or more arguments, but received 0

Note: The message once again indicates that the error is generated by the top-level diff function.

To use a top-level command after its name has been rebound to a package-level command, you must first use the restart; command.

The following example intentionally employs an error message to illustrate which command level is used.

minimize();

Error, invalid input: minimize uses a 1st argument, exprFP (of type algebraic), which is missing

Note: The message refers to the top-level minimize command.

with(simplex);

The simplex package contains a minimize command.

minimize();

Error, invalid input: minimize uses a 1st argument, obj, which is missing

Note: The message refers to the package-level simplex[minimize] command.

:-minimize();

Error, invalid input: minimize uses a 1st argument, obj, which is missing

Note: Packages implemented as tables overwrite any conflicting top-level commands when you invoke the package. You cannot access the top-level command by using the :- syntax.

To use the top-level minimize command, first invoke the restart command.

restart;

minimize();

Error, invalid input: minimize uses a 1st argument, exprFP (of type algebraic), which is missing

Note: The message once again refers to the top-level minimize command.