Re: ISIS: loading data with proper statistical error

On Fri, Nov 30, 2012 at 11:03 -0500, Michael Nowak wrote:
> If I'm remembering this all correctly, the default is for ISIS
> to read the error column in the data file and use that.  So
> perhaps the data is not properly stored in the column.  
> 
> There are a few caveats, however:
> 
> 1) There is a minimum statistical error controlled by a global
> variable, Minimum_Stat_Err, which is normally set to 1 (so bins
> with 0 counts don't get set to 0 error).  I normally reset that
> to 1e-30 for various reasons.  That could change things.

fyi, in the current isis release, load_data supports a
'min_stat_err' qualifier that allows you to specify the minimum
valid statistical error when a dataset is loaded.

I think this is a better way to handle validation of input
statistical errors and is less error prone than setting the
global default to 1.e-30.

> 
> 2)  ISIS does not keep the grouping of the data set - after reading it in, 
> ISIS goes back to unbinned data.

To keep the grouping specified in the PHA file,
set
   Isis_Use_PHA_Grouping=1

Thanks,
-John
----
You received this message because you are
subscribed to the isis-users list.
To unsubscribe, send a message to
isis-users-request_at_email.domain.hiddenwith the first line of the message as:
unsubscribe