variable_domain

functions

SYNTAX

variable_domain(&variable, lower_limit, upper_limit)

DESCRIPTION

Define the domain limits for any variable for which one can take its address. At this time only field editors check the variable domain. If one attempts to enter a value into a field editor which is not in the domain, the value will be set to the upper or lower limit. Important NEURON variables such as dt, L, diam, and Ra have reasonable default domains. Many parameters defined in model description files also have reasonable domains.

This function is most useful when a variable makes sense only as a nonzero or positive number.

One can specify different domains only on a per name basis. Thus there is only one domain specification for L and one for all the instances of IClamp.amp but one can have a different specification for IClamp.amp and VClamp.amp .


chdir

functions

SYNTAX

chdir("path")

DESCRIPTION

Change working directory to the indicated path. Returns 0 if successful otherwise -1, ie the usual unix os shell return style.


units

functions

SYNTAX

current_units = units(&variable)
current_units = units(&variable, "units string")
"on or off" = units(1 or 0)

DESCRIPTION

When units are on (default on) value editor buttons display the units string (if it exists) along with the normal prompt string. Units for L, diam, Ra, t, etc are built-in and units for membrane mechanism variables are declared in the model description file. See modlunit . Note that units are NOT saved in a session. Therefore, any user defined variables must be given units before retrieving a session that shows them in a panel.

The units display may be turned off with units(0) or by setting the *units_on_flag: off in the nrn/lib/nrn.defaults file.

units(&variable) returns the units string for any variable for which an address can be taken.

units(&variable, "units string") sets the units for the indicated variable.

EXAMPLES

execute following example
units(&t) // built in as "ms"
x = 1
{units(&x, "mA/cm2")}	// declare units for variable x
units(&x)		// prints mA/cm2
proc p () {
	xpanel("Panel")
	xvalue("t")
	xvalue("prompt for x", "x", 1)
	xpanel()
}
p()		//shows units in panel
units(0) 	// turn off units
p()		// does not show units in panel


neuron/general/function/0fun.hel : Nov 21 09:16