AMPL commands for Sensitivity Analysis
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display <var name>.rc;		Displays the reduced cost of the variable named <var name>.
display <var name>.down;	Displays, respectively, the lower and upper endpoints of
display <var name>.up;		the range of the objective-function coefficient of the
				variable named <var name> for which the current basis
				remains optimal.
display <var name>.current;	Displays the current value of the objective-function 
				coefficient of the variable named <var name>.

display <constr name>;		Displays the shadow price of the constraint <constr name>.
display <constr name>.down;	Displays, respectively, the lower and upper endpoints of
display <constr name>.up;	the range of the right-hand-side of the constraint named
				<constr name> for which the current basis remains
				feasible, and hence optimal.
display <constr name>.current;	Displays the current value of the right-hand-side of the 
				constraint named <constr name>.
display <constr name>.slack;	Displays the slack in the constraint named <constr name>.

let <name>:=<value>;		Assigns the variable or parameter named <name> the value
				<value>; Useful for making small changes to the LP data. 
				For larger changes, use "reset data; data <new data-file>;"  


Some useful AMPL commands
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expand;		Displays the current LP model with the instantiated data. Useful for
		debugging and in sensitivity analysis to know which LP AMPL is really
		solving. 
		Can also type "expand <name>;", where <name> is the name of a constraint
		or objective function to display only the given constraint or objective
		function instantiated with data.

show;		Displays the names of the sets, parameters, variables, constraints, and
		objective function of current LP model. 
		Can also type "show <name>;" where <name> is the name of a set, parameter,  
		variable, constraint or objective function.

reset;		AMPL always works with a current LP model, and "reset;" resets the current 
		AMPL LP to the empty LP. Useful if you want to solve multiple LPs in the
		same session.

reset data;	Resets only the data of the current LP model retaining the model.


Batch operation OR showing a transcript of AMPL session
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include <filename>;	Executes the AMPL commands in <filename> in sequence as if they
			were typed at the AMPL prompt. Useful for batch operation and
			giving a transcript of the AMPL session - simply save the commands
			you are going to use in the session in <filename>, and type
			"include <filename>;"