Fixed Fractional (Risk) [FF]

Summary:
This position sizing script is used to allocate a fixed percentage of the account equity on each trade.

	 ' Assign the parameters to script variables.
	_fixedFractional = fixedFractional
	_maxUnitLoss = maxUnitLoss
	_enableExitSizing = enableExitSizing
	

	 ' Get the order type.
	Define typeOrder As Integer = OrderType(orderIndex)
	 ' Get the order symbol index.
	Define symbolIndex As Integer = OrderSymbolIndex(orderIndex)
	 ' If the order type is an entry order then calculate the position size.
	If (typeOrder = C_BUY Or _
		typeOrder = C_SELL_SHORT) Then
		 ' Get the bar close of the current bar.
		Define close As Number = BarClose(symbolIndex)
		 ' Check whether the close exists.
		If (close <> 0) Then
			 ' Calculate the number of units to trade.
			Define units As Number = MathFloor((_fixedFractional / 100 * AccountEquity()) / close)
			 ' Check whether the number of units exceeds the specified maximum.
			If (units > _maxUnitLoss) Then
				Return _maxUnitLoss
			End If
			Return units
		Else
			Return 0
		End If
	 ' If the order type is an exit order and the script should handle those.
	Else If (_enableExitSizing)
		 ' If the order type is an exit order then calculate the position size.
		Define openPositions() As Integer = PositionIndexList(C_OPEN)
		For i As Integer = 0 To openPositions.Length - 1
			If (PositionSymbolIndex(openPositions(i)) = symbolIndex) Then
				Return PositionQuantity(openPositions(i))
			End If
		Next
	End If
	Return 0