-- Id: 20998
-- More information about this indicator can be found at:
-- http://fxcodebase.com/code/viewtopic.php?f=17&t=65941

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-- Indicator profile initialization routine

 

function Init()
    indicator:name("!X-UK.NMA.4");
    indicator:description("");
    indicator:requiredSource(core.Tick);
    indicator:type(core.Indicator);
	 
	
	indicator.parameters:addGroup("Calculation"); 
    indicator.parameters:addInteger("MA_Period", "MA_Period", "", 4, 2, 2000);
    indicator.parameters:addInteger("MA_Sampling_Period", "MA_Sampling_Period", "", 4, 2, 2000);
	
	indicator.parameters:addString("MA_Method", "MA Method", "Method" , "MVA");
    indicator.parameters:addStringAlternative("MA_Method", "MVA", "MVA" , "MVA");
    indicator.parameters:addStringAlternative("MA_Method", "EMA", "EMA" , "EMA");
    indicator.parameters:addStringAlternative("MA_Method", "LWMA", "LWMA" , "LWMA");
    indicator.parameters:addStringAlternative("MA_Method", "TMA", "TMA" , "TMA");
    indicator.parameters:addStringAlternative("MA_Method", "SMMA", "SMMA" , "SMMA");
    indicator.parameters:addStringAlternative("MA_Method", "KAMA", "KAMA" , "KAMA");
    indicator.parameters:addStringAlternative("MA_Method", "VIDYA", "VIDYA" , "VIDYA");
    indicator.parameters:addStringAlternative("MA_Method", "WMA", "WMA" , "WMA");
 
	
	indicator.parameters:addGroup("Style"); 	
    indicator.parameters:addColor("Up", "Up Slope Line Color", "", core.rgb(0, 255, 0));
	indicator.parameters:addColor("Down", "Down Slope Line Color", "", core.rgb(255, 0, 0));
	indicator.parameters:addInteger("style", "Line Style", "", core.LINE_SOLID);
    indicator.parameters:setFlag("style", core.FLAG_LEVEL_STYLE);	
	indicator.parameters:addInteger("width", "Line Width", "", 3, 1, 5);
	
end

-- Indicator instance initialization routine
-- Processes indicator parameters and creates output streams
-- Parameters block

local MA_Period, MA_Sampling_Period,MA_Method; 
local first;
local source = nil;
 
local Oscillator;  
local Lambda, Alpha;
local MA1,MA2;
-- Routine
 function Prepare(nameOnly)   
 
    MA_Period = instance.parameters.MA_Period;
	MA_Sampling_Period = instance.parameters.MA_Sampling_Period;
	MA_Method = instance.parameters.MA_Method; 
 
    local name = profile:id() .. "(" ..  instance.source:name() .. ", " ..  MA_Period .. ", " ..  MA_Sampling_Period  .. ", " ..  MA_Method.. ")";
    instance:name(name); 


    if   (nameOnly) then
        return;
    end

 
			
    source = instance.source;
 
	  Lambda = MA_Period / MA_Sampling_Period
      if(Lambda < 2.0) then
     
         Lambda = 2.0;
         MA_Sampling_Period = MA_Period / 2.0;
     end
	  
	  
	 
     Alpha  = Lambda * (MA_Period - 1.0) / (MA_Period - Lambda);
	
    assert(core.indicators:findIndicator(MA_Method) ~= nil, MA_Method .. " indicator must be installed");
	MA1 = core.indicators:create(MA_Method, source, MA_Period);
    MA2 = core.indicators:create(MA_Method, MA1.DATA, MA_Sampling_Period);
	
	first=MA2.DATA:first();
 
	Oscillator = instance:addStream("Oscillator" , core.Line, " Oscillator"," Oscillator",instance.parameters.Up, first);
	Oscillator:setWidth(instance.parameters.width);
    Oscillator:setStyle(instance.parameters.style);
    
	
	
end

-- Indicator calculation routine
function Update(period, mode)
 
	
    if period < first then
	return;
	end
	
	MA1:update(mode);
	MA2:update(mode); 
	 
 
	
	Oscillator[period] = (Alpha+1.0)*MA1.DATA[period] - Alpha*MA2.DATA[period];
	
	if Oscillator[period] > Oscillator[period-1] then 
	Oscillator:setColor(period, instance.parameters.Up);
	else
	Oscillator:setColor(period, instance.parameters.Down);
	end
				  
end