You are accessing an index with a value that is invalid out-of-range

[tackaway]

I have looked at other threads for a similar post, however I am not able to figure this out. My strategy is comparing LinReg over a time frame. I want to look at the current LinReg comapred to that of 30 bars ago. I have the following:

double curVal = LinReg(20)[0];
double pastVal = LinReg(20)[30];

I keep getting the error mentioned in the title, saying there are only "Error on calling 'OnBarUpdate' method on bar 0: You are accessing an index with a value that is invalid since it is out-of-range. I.E. accessing a series [barsAgo] with a value of 5 when there are only 4 bars on the chart."

I have in the code as well

Print("Current Bar: " + CurrentBar);

which does in fact return a number that is greater than 30. How can I access the data from a bar that is 30 before the current one?

[bltdavid]

Are you waiting for at least 30 bars before doing that check?

protected override void OnBarUpdate()
{
    if (CurrentBar < 30)
       return;

    ... rest of your code ...

}