Indicator calculation loops and the beginning index – Different – 8 February 2025

When an indicator first masses, prev_calculated is 0 on the firs execution. On subsequent calls, prev_calculated holds the variety of bars that had been processed within the earlier execution.

So when the indicator has has calculated a couple of bar, prev_calculated – 1 might be accepted because the final processed bar and is an environment friendly start line for future calculations if solely the present bar within the indicator is important to be up to date on every recalculation.

If the indicator should replace X bars at a time like within the Fractals indicator (instance 5 bars), then the beginning index needs to be prev_calculated – 5.

When prev_calculated == 0 (first execution), the indicator must calculate the preliminary knowledge.

In some customized indicators, you want sufficient historic knowledge factors to appropriately calculate the buffers, this could be for instance pivot indicators the place the result’s obtained based mostly on a interval of bars. This additionally applies to indicators that don’t use CopyBuffer.

In thiskind of indicator, you may have a begin index like this:

it begin = (prev_calculated == 0) ?  period_var : prev_calculated – 1;

or else

int begin = (prev_calculated < period_var) ? period_var : prev_calculated – 1;

In case you wished to create bar confirmations, then you definitely would alter the beginning index to assist this:

int begin = (prev_calculated == 0) ? period_var : prev_calculated - (bar_confirmations + 1);

( + 1 needs to be added to bar_confirmations to account for the truth that “bar_confirmations” might be 0 and prev_calculated – 1 is the final calculated bar)

Prev_calculated can theoretically be -1 (although normally 0) or better than rates_total.

In some indicators iMA equal bars are copied with copybuffer and there’s no strict minimal variety of bars required. If prev_calculated < 0, restarting from 0 might be completed to stop errors with the plotting, however it ought to begin the replace from the final copied bar when prev_calculated is bigger or equal to 0.

When copying bars in an indicator with copybuffer, it’s greatest to not copy all charges/bars as a result of it will probably decelerate the indicator, which can then additionally decelerate an EA if the indicator is instantiated within the EA with iCustom.

To correctly and safely copy bars, it’s worthwhile to be sure that prev_calculated isn’t lower than 0 and never better than rates_total. Whether it is, copy all bars quickly, in any other case solely copy new unprocessed bars. Then it doesn’t have to recalculate every thing on every execution.

if(prev_calculated > rates_total || prev_calculated < 0){

      to_copy = rates_total;
}
else
{
      to_copy = rates_total - prev_calculated;

      if(prev_calculated > 0) to_copy++;
}

or

if(prev_calculated > rates_total || prev_calculated < 0)
{
      to_copy = rates_total;
}
else
{
      to_copy = rates_total - prev_calculated + 1;
}

 Lastly name the CopyBuffer operate to repeat the info into your plot buffer:

 if(CopyBuffer(deal with, 0, 0, to_copy, buffer) < 0){

     Print(“Errror encountered copying bars, please stand by.”);

      ChartRedraw();
   }