- lets choose different color for up and down parts of SAR
- lets choose step and maximum values (default values are 0.02 and 0.2)
- Code: Select all
-- The indicator corresponds to the Parabolic indicator in MetaTrader.
-- The formula is described in the Kaufman "Trading Systems and Methods" chapter 5 "Trend Systems" (page 98-99)
-- Indicator profile initialization routine
-- Defines indicator profile properties and indicator parameters
function Init()
indicator:name("Color SAR");
indicator:description("Helps to define the direction of the prevailing trend and the moment to close positions opened during the reversal.");
indicator:requiredSource(core.Bar);
indicator:type(core.Indicator);
indicator.parameters:addDouble("Step", "Step", "", 0.02, 0.001, 1);
indicator.parameters:addDouble("Max", "Max", "", 0.2, 0.001, 10);
indicator.parameters:addColor("clrUp", "Up Line Color", "", core.rgb(255, 0, 0));
indicator.parameters:addColor("clrDown", "Down Line Color", "", core.rgb(0, 255, 0));
end
-- Indicator instance initialization routine
-- Processes indicator parameters and creates output streams
-- Parameters block
local first;
local source = nil;
local tradeHigh = nil;
local tradeLow = nil;
local parOp = nil;
local position = nil;
local af = nil;
local Step;
local Max;
-- Streams block
local SAR = nil;
local UP = nil;
local DOWN = nil;
-- Routine
function Prepare()
source = instance.source;
first = source:first() + 1;
Step = instance.parameters.Step;
Max = instance.parameters.Max;
local name = profile:id() .. "(" .. source:name() .. "," .. Step .. "," .. Max .. ")";
instance:name(name);
tradeHigh = instance:addInternalStream(0, 0);
tradeLow = instance:addInternalStream(0, 0);
parOp = instance:addInternalStream(0, 0);
position = instance:addInternalStream(0, 0);
af = instance:addInternalStream(0, 0);
SAR = instance:addInternalStream(first, 0);
UP = instance:addStream("UP", core.Dot, name .. ".Up", "UP", instance.parameters.clrUp, first)
DOWN = instance:addStream("DN", core.Dot, name .. ".Dn", "DN", instance.parameters.clrDown, first)
end
-- Indicator calculation routine
function Update(period)
local init = Step;
local quant = Step;
local maxVal = Max;
local lastHighest = 0;
local lastLowest = 0;
local high = 0;
local low = 0;
local prevHigh = 0;
local prevLow = 0;
if period >= first then
high = source.high[period];
low = source.low[period];
prevHigh = source.high[period - 1];
prevLow = source.low[period - 1];
if (period == first) then
tradeHigh[period] = prevHigh;
tradeLow[period] = prevLow;
position[period] = -1;
parOp[period] = prevHigh;
af[period] = 0;
else
parOp[period] = parOp[period - 1];
position[period] = position[period - 1];
tradeHigh[period] = tradeHigh[period - 1];
tradeLow[period] = tradeLow[period - 1];
af[period] = af[period - 1];
end
lastHighest = tradeHigh[period];
lastLowest = tradeLow[period];
if high > lastHighest then
tradeHigh[period] = high;
end
if low < lastLowest then
tradeLow[period] = low;
end
if position[period] == 1 then
if (low < parOp[period]) then
position[period] = -1;
SAR[period] = lastHighest;
tradeHigh[period] = high;
tradeLow[period] = low;
af[period] = init;
parOp[period] = SAR[period] + af[period] * (tradeLow[period] - SAR[period]);
if (parOp[period] < high) then
parOp[period] = high;
end
if (parOp[period] < prevHigh) then
parOp[period] = prevHigh;
end
else
SAR[period] = parOp[period];
if (tradeHigh[period] > tradeHigh[period - 1] and af[period] < maxVal) then
af[period] = af[period] + quant;
if af[period] > maxVal then
af[period] = maxVal;
end
end
parOp[period] = SAR[period] + af[period] * (tradeHigh[period] - SAR[period]);
if (parOp[period] > low) then
parOp[period] = low;
end
if (parOp[period] > prevLow) then
parOp[period] = prevLow;
end
end
else
if (high > parOp[period]) then
position[period] = 1;
SAR[period] = lastLowest;
tradeHigh[period] = high;
tradeLow[period] = low;
af[period] = init;
parOp[period] = SAR[period] + af[period] * (tradeHigh[period] - SAR[period]);
if (parOp[period] > low) then
parOp[period] = low;
end
if (parOp[period] > prevLow) then
parOp[period] = prevLow;
end
else
SAR[period] = parOp[period];
if (tradeLow[period] < tradeLow[period - 1] and af[period] < maxVal) then
af[period] = af[period] + quant;
if af[period] > maxVal then
af[period] = maxVal;
end
end
parOp[period] = SAR[period] + af[period] * (tradeLow[period] - SAR[period]);
if (parOp[period] < high) then
parOp[period] = high;
end
if (parOp[period] < prevHigh) then
parOp[period] = prevHigh;
end
end
end
if position[period] == 1 then
DOWN[period] = SAR[period];
else
UP[period] = SAR[period];
end
end
end
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