Hi, I would like to subtract some unwanted events to recreate a leaf using:
auto new_events = df.Define("unwanted_events", "Take(myleaf1, myleaf1.size() > myleaf2.size())") // exclude these events
.Define("new_events", "total_events - unwanted_events"); // the problem is here
auto h = new_events.Histo1D("new_events");
I am getting the error:
Cannot call operator - on vectors of different sizes.
I understand that both vectors total_events and unwanted_events have different sizes, but what other way I can use to subtract them?
EDIT: example of data:
Notice event 4037. I want the whole event or preferably only particle  out.
I’m not sure I understand the use of
Take(). To me it looks like you’d like to just filter some events, like this
df.Define("isBadEvent", "myleaf1.size() > myleaf2.size()")
It’s to define the bad events then filter for them.
auto c1 = df.Define("unwanted_events", "Take(myleaf1, myleaf1.size() > myleaf2.size())") // exclude these events
.Define("total_events", "myleaf1") //original leaf
.Filter("!unwanted_events") // filter bad events out
auto h = c1.Histo1D("new_events"); // draw original leaf (bad events excluded)
But I am getting an error:
error: no viable conversion from returned value of type 'RVec<unsigned int>' to
function return type 'bool'
EDIT: Actually it’s one bad particle located in index  of some events. So if I can say somehow, exclude myleaf1 and return myleaf1, that would be it. I managed to define those indices using first code line, but I am so far unable to filter it out.
If I understand correctly, you should be able to do something like this
df.Define("cleaned_myleaf1", "myleaf1[ myleaf1 < 42 ]")
What this does is it creates a new vector column “cleaned_myleaf1” that has only those elements from “myleaf1” for which the condition element < 42 holds. Of course you’d need to adjust the condition
myleaf1 < 42 to whatever renders a particle as “good particle”.
Thanks for your answer.
Correct, and what this does is, defining for the first column, which is events (see photo above). What I would like to do is to control the index (column 2). So maybe something like:
So this should take out all index 3 and return column. But unfortunately it does not work.
I hope it is more clear now what I want to do
Oh, now I also understand the use of
Take. So that should work
df.Define("cleaned_myleaf1", "Take(myleaf1, myleaf2.size())");
I.e. cleaned_myleaf1 takes only the first elements of myleaf1, where “the first” are as many as the size of myleaf2.
Actually it is my fault. I was defining bad events. Instead, I could define good events and see what to do with them.
Apologies and thanks for your help.
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