! midas procedure snr.prg
! author: E. Pompei
! Created: 2003 - La Silla
! Purpose: does a quick and dirty
!          estimate of the S/N,
!	   assuming Poisson noise
!          and a 1D spectra.


! input files in .bdf format

write/out "***********************************"
write/out "*	MIDAS PROCEDURE QUICKRED     *"
write/out "***********************************"

define/local low/r/1/1 0.
define/local up/r/1/1 0.
define/local argh/i/1/1 0

again: 

low = 0.
up = 0.
argh = 0

set/gra xaxis=auto
set/gra yaxis=auto
set/gra pmode=1
inquire/keyword basso/r/1/1 "Please type the lower lambda (angstrom)"
inquire/keyword alto/r/1/1 "Please type the upper lambda (angstrom)"

low = {basso}
up = {alto}

set/gra xaxis={low},{up}
set/gra yaxis=auto
plot {p3}
write/out "Click on line-free part of the spectra;"
write/out "and press middle mouse button to get out"
get/gcurs tmp
stat/table tmp :value
write/out "Your S/N (assuming Poisson noise) is:"
comp sqrt({OUTPUTR(3)})

inquire/keyword deci/c/1/1 "Do you wish to try again? Y/N"

if deci .EQ. "Y" then
goto again
endif