-- program to extract the values of gradient strength from a Varian DOSY experiment
-- run this script ONCE to let iNMR process the current spectrum as a DOSY
-- no need to run it again in future, because the results are saved into a file called "zeta"

function ValueNamed( name )
local len = string.len( name ) + 1
name = name.." "
local line
repeat
	line = string.sub( io.read("*line"), 1, len )
until line == name
_ = io.read("*number")		-- skip the first number
return io.read("*number")
end

function ArrayNamed( name )
local len = string.len( name )
local line
T = {}
repeat
	line = string.sub( io.read("*line"), 1, len )
until line == name
local n = io.read("*number")		-- the first number is the length of the array
for i=1,n do
	T[i] = io.read("*number")
end
return n, T
end

-- the main program starts here
print "\n\n============================="
local path = pathtofile()
last = 1
while true do
	slash = string.find( path, "/", last + 1 )
	if not slash then break end
	last = slash
end
path = string.sub( path, 1, last )		-- path to the folder
io.input( path.."procpar" )

-- the following parameters must be found exactly in this order...
DAC_to_G = 0.01 * ValueNamed( "DAC_to_G" )		-- calibration
DELTA = ValueNamed( "del" )
dosytimecubed = ValueNamed( "dosytimecubed" )
dosygamma = ValueNamed( "dosygamma" )	-- gyromagnetic ratio
delta = ValueNamed( "gt1" )
n, gzlvl1 = ArrayNamed( "gzlvl1" )		-- gradient strength
-- ... otherwise they are not found: in this case, rewrite the script

D_d = DELTA - delta / 3
--Dconst = dosygamma * dosygamma * delta * delta * D_d  -- UNCOMMENT IF DOSYTIMECUBED IS NOT FOUND
Dconst = dosytimecubed * dosygamma * dosygamma  		-- COMMENT IF DOSYTIMECUBED IS NOT FOUND
print( "DELTA = ", DELTA )
print( "delta = ", delta )
print( "dosygamma = ", dosygamma )
print( "DOSYconstant = ", Dconst )

io.output( path.."zeta" )
for i = 1,n do
	local G = DAC_to_G * gzlvl1[i]
--	print( G )
	io.write( G * G * Dconst, "\n" )		-- values required by iNMR (independent variable)
end	
	
io.close( )		-- closing and saving the output file zeta
print (n, "values extracted and converted")