/* Exponential Smoothing */

options results
if ~show('P','TCALC') then do
	address command 'run sys:turbocalc/turbocalc'
	address command 'waitforport TCALC'
	loadflag=1
end
address 'TCALC'
/* Add-in Rexx Math Library needed for some routines */
signal on syntax
if ~show('l','rexxmathlib.library') then
   call addlib('rexxmathlib.library',0,-30)
if ~show('l','rexxreqtools.library') then
   call addlib('rexxreqtools.library',0,-30)
  /* add to library list */
signal off syntax

/* Start Main Routine */
if loadflag=1 then 'Load()'
'ActivateWindow()'
;'LiesCursorPos'
range=rtgetstring(,"Enter Cell Range for Input","Input Request",,'rt_pubscrname="TurboCalc"')
colon=pos(":",range)
if colon=0 then do
	'Message "Please select a range~before executing this script"'
	exit
end

/* Find cell references and cell, column numbers */
start_cell=substr(range,1,colon-1)
end_cell=substr(range,colon+1)
start_row=cellrow(start_cell)
end_row=cellrow(end_cell)
start_col=cellcol(start_cell)
end_col=cellcol(end_cell)
NRows=end_row-start_row+1
NCols=end_col-start_col+1
if NCols>1 then do
	'Message "Only one column allowed"'
	exit
end

/* Get cell reference for output range */
out_cell=rtgetstring(,"Enter Cell Reference for Output","Input Request",,'rt_pubscrname="TurboCalc"')
if out_cell="" then exit
if length(out_cell)<2 | datatype(left(out_cell,1),'n') then do
	'Message "Invalid cell reference"'
	exit
end
inval=rtgetlong("3","Enter number of intervals (default=3)","Input Request",,'rt_pubscrname="TurboCalc"')

/* Suppress Screen Redraw to Speed Things Up */
'Refresh 0'

/* Get cell references for top cell in each column */
'SelectCell' start_cell
do col=start_col to end_col
	'GetCursorPos'
	top_cell.col=result
	'Column 1'
end

/* Get data from cell range */
col=start_col
lav=0
tot=0
count.=0
total.=0
data.=0
do x=1 to NCols
	'SelectCell' top_cell.col
	do y=1 to NRows
		'GetValue'
		valtest=result
		if datatype(valtest)='NUM' then do
			'GetValue'
			val=result
			val=strip(val)
			data.x.y=val
			tot=tot+val
			total.x=tot
			count.x=1+count.x
		end
		'Down 1'
	end
	col=col+1
	tot=0
	lav=0
	val=0
end

/* Calculate Forecast Values */
z=1
x=1
dact.=0
summ.=0
Fval.=0
do y=inval to NRows
	z=y
	do i=z to z-inval+1 by -1
	summ.y=(data.x.i)+summ.y
	end		
	Fval.x.y=(summ.y)/inval
end
do y=inval to NRows
	dact.y=((data.x.y)-(Fval.x.y))**2
end
do w=1 to inval+1
	serr.w=0
end
N=2
do w=inval+2 to NRows
	z=w
	do i=z to z-inval+1 by -1
	summ.w=(summ.w)+(dact.i)
	end
	serr.w=sqrt((summ.w)/inval)
end

/* Output */
'SelectCell' out_cell
'ColumnWidth 10'
do y=1 to NRows
	'Put' Fval.x.y
	'Down 1'
end
'Put' "Forecast"
'Down 2'
'Put " Interval="'
'SelectCell' out_cell
'Column 1'
do y=1 to NRows
	'Put' serr.y
	'Down 1'
end
'Put "St. Error"'
'Down 2'
'Put' inval
'Refresh 1'
'Refresh 2'
'Message' "Finished"
exit

/* Procedures */

cellrow: procedure
do
	parse arg cell
	do charpos=2 to length(cell)
	if datatype(substr(cell,charpos,1),n) then return substr(cell,charpos)
	end
	return 0
end
Return

cellcol: procedure
do
	parse arg cell
	labels="ABCDEFGHIJKLMNOPQRSTUVWXYZ"
	cell=upper(cell)
	len=length(cell)
	val=0
do charpos=1 to len
	if datatype(substr(cell,charpos,1),n) then
	do cell=reverse(substr(cell,1,charpos-1))
	do x=1 to length(cell)
	val=(26**(x-1))*pos(substr(cell,x,1),labels)+val
	end
	return val
	end
	end
	return 0
end
Return

syntax:
      if arg(1)='FAIL' then do
         'Message "Library is unavailable."'
         exit
         end