8.0.0.3 Bar Index Off by One in OnRender()?

[dalebru]

I'm not sure if this is a bug, or if I just misunderstand something very fundamental. I ran across this doing a conversion from NT7 to NT8. At the least, something seems to have changed.
I've attached a tiny indicator that shows the issue. But here is an attempt to describe the issue.
OnBarUpdate() behaves as expected -- the index is the same as the CurrentBar
protected override void OnBarUpdate()
{
if (CurrentBar % 2 == 0)
{
Signals[0] = CurrentBar;
}
var isValid = Signals.IsValidDataPoint(0);
Print(string.Format("isValid={0} at {1}", isValid, CurrentBar));
if (isValid)
{
var signal = Signals.GetValueAt(CurrentBar);
Print(string.Format("signal={0} at {1}", signal, CurrentBar));
}
}

But OnRender() has a very different behavior (unless I'm missing something major!).
var ADJUSTMENT = 1;
Print(string.Format("Bars.Count={0},ChartBars.Coun t={1}", Bars.Count, ChartBars.Count));
for (int idx = ChartBars.FromIndex; idx <= ChartBars.ToIndex; idx++)
{
var isValidSignal = Signals.IsValidDataPoint(Bars.Count - 1 - idx);
Print(string.Format("At idx={0} isValidSignal={1}", idx, isValidSignal));

if (!isValidSignal)
{
continue;
}
var signal = Signals.GetValueAt(idx - ADJUSTMENT);
Print(string.Format("At idx={0} signal={1}", idx, signal));
}

So you can see that I have to subtract 1 from the idx for Signals.GetValueAt() but NOT for Signals.IsValidDataPoint(), otherwise I get 0 (wrong) values for the Signals setting at idx.

For example, in the Output window, OnBarUpdate gives me:
isValid=False at 85
isValid=True at 86
signal=86 at 86
isValid=False at 87

But OnRender gives me:
At idx=86 isValidSignal=False
At idx=87 isValidSignal=True
At idx=87 signal=86
At idx=88 isValidSignal=False

Thanks for your help,
Dale

[RJay]

I'm not sure if this is a bug, or if I just misunderstand something very fundamental. I ran across this doing a conversion from NT7 to NT8. At the least, something seems to have changed.
I've attached a tiny indicator that shows the issue. But here is an attempt to describe the issue.
OnBarUpdate() behaves as expected -- the index is the same as the CurrentBar
protected override void OnBarUpdate()
{
if (CurrentBar % 2 == 0)
{
Signals[0] = CurrentBar;
}
var isValid = Signals.IsValidDataPoint(0);
Print(string.Format("isValid={0} at {1}", isValid, CurrentBar));
if (isValid)
{
var signal = Signals.GetValueAt(CurrentBar);
Print(string.Format("signal={0} at {1}", signal, CurrentBar));
}
}

But OnRender() has a very different behavior (unless I'm missing something major!).
var ADJUSTMENT = 1;
Print(string.Format("Bars.Count={0},ChartBars.Coun t={1}", Bars.Count, ChartBars.Count));
for (int idx = ChartBars.FromIndex; idx <= ChartBars.ToIndex; idx++)
{
var isValidSignal = Signals.IsValidDataPoint(Bars.Count - 1 - idx);
Print(string.Format("At idx={0} isValidSignal={1}", idx, isValidSignal));

if (!isValidSignal)
{
continue;
}
var signal = Signals.GetValueAt(idx - ADJUSTMENT);
Print(string.Format("At idx={0} signal={1}", idx, signal));
}

So you can see that I have to subtract 1 from the idx for Signals.GetValueAt() but NOT for Signals.IsValidDataPoint(), otherwise I get 0 (wrong) values for the Signals setting at idx.

For example, in the Output window, OnBarUpdate gives me:
isValid=False at 85
isValid=True at 86
signal=86 at 86
isValid=False at 87

But OnRender gives me:
At idx=86 isValidSignal=False
At idx=87 isValidSignal=True
At idx=87 signal=86
At idx=88 isValidSignal=False

Thanks for your help,
Dale

Try it again after making the following change.

From: Calculate = Calculate.OnBarClose;

To: Calculate = Calculate.OnPriceChange;

Or To: Calculate = Calculate.OnEachTick;

[dalebru]

Try it again after making the following change.

From: Calculate = Calculate.OnBarClose;

To: Calculate = Calculate.OnPriceChange;

Or To: Calculate = Calculate.OnEachTick;

Thank you RJay. That "explains" it. I'm shocked that I've programmed NinjaScript for so long without understanding this quirk.
NinjaTrader, I'm ready to declare this "not a bug."
For anyone interested, attached are two more simple indicators showing that the behavior is the same in NT7 and NT8.
Amazingly, I don't need to adjust for Calculate.OnBarClose if I use the indexer, i.e. Signals[barsAgo]. I only need to adjust for it if I use the Signal.GetValueAt(index).

Thanks again,
Dale