Summation (Variable Length) [SumVL]

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The Summation (Variable Length) function adds together the values of a data series over a variable number of bars. Parameters ------------------ Data          The data to use in the calculation. This is typically a field in a data series or a calculated value. Period        The number of bars of data to include in the sample, including the current value.                   For example, a period of 3 includes the current value and the two previous values. Maximum Period   The maximum value that Period can contain.                              Larger values require extra memory to be set aside for this function to be calculated. Note: An end point to the Period parameter can be simulated using the Lag function to obtain a previous value of this function. See the notes for the Lag function for more information. Function Value ------------------------ This function adds together the values of a data series over a given period. This is useful for creating moving averages and other calculations which include more than one previous value. The summation at the beginning of a data series is not defined until there are enough values to fill the given period.  If the period is greater than the maximum period or negative, the value is not defined. If the period contains a fractional number, only the integer portion will be used. Data    Period   SumVL(Data,Period,3) ------------------------------------------------------------   0            3   1            2   2            1                    2   4            2                    6   8            3                    14   7            4                                 <-- no value since 4 > maximum period   6            3                    21 The summation function can also be used with the Summation Bars Ago function or the Summation Index function to vary the processing of the elements. See the description of those functions for more information. Variable length functions can be used in association with other calculations, such as "Bars Since" functions, to determine values since an event occurred. For example, the following formula would return the sum of the High field since the highest high in the last ten bars: SumVL ( High, Add ( BarsSinceHigh ( High, 10 ) , 1 ) , 10)