input numDevDn = -2.0;
input numDevUp = 2.0;
input timeFrame = {default DAY, WEEK, MONTH};
def cap = getAggregationPeriod();
def errorInAggregation =
timeFrame == timeFrame.DAY and cap >= AggregationPeriod.WEEK or
timeFrame == timeFrame.WEEK and cap >= AggregationPeriod.MONTH;
assert(!errorInAggregation, "timeFrame should be not less than current chart aggregation period");
def yyyyMmDd = getYyyyMmDd();
def periodIndx;
switch (timeFrame) {
case DAY:
periodIndx = yyyyMmDd;
case WEEK:
periodIndx = Floor((daysFromDate(first(yyyyMmDd)) + getDayOfWeek(first(yyyyMmDd))) / 7);
case MONTH:
periodIndx = roundDown(yyyyMmDd / 100, 0);
}
def isPeriodRolled = compoundValue(1, periodIndx != periodIndx[1], yes);
def volumeSum;
def volumeVwapSum;
def volumeVwap2Sum;
if (isPeriodRolled) {
volumeSum = volume;
volumeVwapSum = volume * vwap;
volumeVwap2Sum = volume * Sqr(vwap);
} else {
volumeSum = compoundValue(1, volumeSum[1] + volume, volume);
volumeVwapSum = compoundValue(1, volumeVwapSum[1] + volume * vwap, volume * vwap);
volumeVwap2Sum = compoundValue(1, volumeVwap2Sum[1] + volume * Sqr(vwap), volume * Sqr(vwap));
}
def price = volumeVwapSum / volumeSum;
def deviation = Sqrt(Max(volumeVwap2Sum / volumeSum - Sqr(price), 0));
def upper = price + numDevUp * deviation;
def lower = price + numDevDn * deviation;
def currentbar = if !isnan(close) && isnan(close[-1]) then barnumber() else double.nan;
def vwap_line = if barnumber() == currentbar then price else double.nan;
def upper_line = if barnumber() == currentbar then upper else double.nan;
def lower_line = if barnumber() == currentbar then lower else double.nan;
plot VWAP = highestall(vwap_line);
plot UpperBand = highestall(upper_line);
plot LowerBand = highestall(lower_line);
VWAP.setDefaultColor(getColor(0));
UpperBand.setDefaultColor(getColor(2));
LowerBand.setDefaultColor(getColor(4));