VISIT

Type:

Command

 

 

Description:

For a specified variable, opens the contents in the command-line editor.

Access:

…µVISIT or „˜

 

 

Input/Output:

 

 

 

 

 

 

 

 

 

 

 

Level 1/Argument 1

 

Level 1/Item 1

 

 

 

 

 

 

 

A variable name

→

The contents opened in the command line

 

 

 

 

editor.

 

 

 

 

 

See also:

VISITB, EDIT, EDITB

 

 

 

 

 

 

 

VISITB

Command

 

 

Type:

 

 

Description:

For a specified variable, opens the contents in the most suitable editor for the object type. For

 

example, if the specified variable holds an equation, the equation is opened in Equation Writer.

Access:

…µVISITB

 

 

Input/Output:

 

 

 

 

 

 

 

 

 

 

 

Level 1/Argument 1

 

Level 1/Item 1

 

 

 

 

 

 

 

A variable name

→

The contents opened in the most suitable

 

 

 

 

editor.

 

 

 

 

 

See also:

VISIT, EDIT, EDITB

 

 

 

 

 

 

 

VPOTENTIAL

 

 

 

 

Type:

Command

 

 

Description:

Find a vector potential function describing a field whose curl (or “rot”) is the input. This

 

command is the opposite of CURL. Given a vector V it attempts to return a function U such that

curl U is equal to V; ∇ ⋅U = V . For this to be possible, DIV(V) must be zero, otherwise the command reports a “Bad Argument Value” error. Step-by-step mode is available with this command.

Access: Catalog, …µ

Input: Level 2/Argument 1: A vector V of expressions.

Level 1/Argument 2: A vector of the names of the variables.

Output: Level 1/Item 1: A vector U of the variables that is the potential from which V is obtained. An arbitrary constant can be added, the command does not do this.

Flags: Exact mode must be set (flag –105 clear). Numeric mode must not be set (flag –3 clear). Radians mode must be set (flag –17 set). Step-by-step mode can be set (flag –100 set).

Example: To see if this command is the opposite of CURL, use the output of the example in CURL as input to VPOTENTIAL. Find a vector in the spatial variables x, y, and z whose curl is: (2yz)i + (0)j + (2xy – x2)k

Command: VPOTENTIAL([2*Y*Z, 0, 2*X*Y-X^2], [X,Y,Z])

EXPAND(ANS(1))

Result: [0, -((X^3-3*Y*X^2)/3), Z*Y^2]

This shows that the reversal is not unique – more than one vector can have the same curl.

Full Command and Function Reference 3-271