;+
; timeit
;
; PURPOSE:
;    test how long a given IDL command takes to execute. 
;
; NOTES:
;
; takes a string specifying an idl command. Executes it some number of times
; (default=5) and prints the mean execution time.
;
; This actually has to be implemented as a batch file so that it executes at 
; the same level of IDL rather than going inside of a procedure or function
; call, since then none of your variables would be accessible and the
; statement you want to time would presumably not work.
;
; USAGE:
;
;  IDL> cmdstr="some string of commands"
;  [optional:  IDL> timeitloops=<somenumber>]
;  IDL> @timeit
;  
; HISTORY:
;    2001-07-25 by Marshall Perrin
;
;-

if not(keyword_set(timeitloops)) then timeitloops=5
	timeitr=fltarr(timeitloops)

for timeit=0,timeitloops-1 do begin &$
	timeit1=systime(/seconds) &$
	timeite=execute(cmdstr) &$
 	timeit2=systime(/seconds) &$
	timeitr[timeit]=timeit2-timeit1 &$
	print,"TIMEIT: execution took "+strc(timeitr[timeit])," seconds" &$
endfor
timeitmean = mean(timeitr)
timeitstddev = stddev(timeitr)
print,"TIMEIT: Average "+strc(timeitmean)+", stddev "+strc(timeitstddev)