Bug #3541

csspec aborts if there is an energy bin with 0 observed/predicted events

Added by Tibaldo Luigi about 3 years ago. Updated almost 3 years ago.

Status:ClosedStart date:02/17/2021
Priority:UrgentDue date:
Assigned To:Knödlseder Jürgen% Done:

100%

Category:-
Target version:2.0.0
Duration:

Description

This issue was reported by Marianne, here’s an extract from the debug output

2021-02-16T16:27:33: +===================+
2021-02-16T16:27:33: | Input observation |
2021-02-16T16:27:33: +===================+
2021-02-16T16:27:33: === GObservations ===
2021-02-16T16:27:33:  Number of observations ....: 1
2021-02-16T16:27:33:  Number of models ..........: 2
2021-02-16T16:27:33:  Number of observed events .: 0
2021-02-16T16:27:33:  Number of predicted events : 0
2021-02-16T16:27:33:
2021-02-16T16:27:33: +=================================+
2021-02-16T16:27:33: | Maximum likelihood optimisation |
2021-02-16T16:27:33: +=================================+
terminate called after throwing an instance of 'GException::empty'
  what():  *** ERROR in GMatrixSparse::GMatrixSparse(int&, int&, int&): Zero-size allocation.
Aborted

A likelihood fit can certainly not work with 0 observed and predicted events, we should add a check and skip bins for which this situation occurs.


Recurrence

No recurrence.

History

#1 Updated by Knödlseder Jürgen almost 3 years ago

  • Priority changed from Normal to High
  • Target version set to 2.0.0

I have this same error recently quite often, not sure why it did not show up before.

#2 Updated by Knödlseder Jürgen almost 3 years ago

  • Status changed from New to In Progress
  • Assigned To set to Knödlseder Jürgen
  • % Done changed from 0 to 10

I modified the

GMatrixSparse::GMatrixSparse(const int& rows, const int& columns, const int& elements)
constructor so that it allows also zero number of rows or columns. This was a todo that was identified. Nevertheless, I need to check that the sparse matrix class allows to operate on empty matrices. I did the same in the GMatrix and GMatrixSymmetric class.

#3 Updated by Knödlseder Jürgen almost 3 years ago

It seems that the sparse matrix class is not yet working properly on empty matrices:

0   libgamma.8.dylib                  0x0000000107e9e6b9 cs_transpose(GMatrixSparse const&, int) + 121 (GMatrixSparse.cpp:3810)
1   libgamma.8.dylib                  0x0000000107e9e5d0 GMatrixSparse::transpose() const + 224

#4 Updated by Knödlseder Jürgen almost 3 years ago

  • Project changed from ctools to GammaLib
  • Target version deleted (2.0.0)
  • % Done changed from 10 to 30

I added unit tests to verify that all methods and operators of GMatrixSparse work seamlessly on empty matrices. This needed a few code adaptions.

I still need to do the same for the other two storage classes.

#5 Updated by Knödlseder Jürgen almost 3 years ago

  • Target version set to 2.0.0

#6 Updated by Knödlseder Jürgen almost 3 years ago

  • Status changed from In Progress to Pull request
  • % Done changed from 30 to 90

I implement unit tests also for all other storage classes. Things seem to work well now.

In addition, I modified the code in GObservation and GResponse so that no issues occur in case that there are no events. I tested the code on cssens where I had the same error before and now it works fine.

#7 Updated by Knödlseder Jürgen almost 3 years ago

  • Status changed from Pull request to Closed
  • % Done changed from 90 to 100

The code was merged into devel.

#8 Updated by Knödlseder Jürgen almost 3 years ago

  • Status changed from Closed to In Progress
  • Priority changed from High to Urgent
  • % Done changed from 100 to 50

There seems still to be a problem when passing an observation without any event. Such a problem occurs in the csphasecrv unit test.

#9 Updated by Knödlseder Jürgen almost 3 years ago

  • Status changed from In Progress to Pull request
  • % Done changed from 50 to 90

Found it. It was an exception in GMatrixSparse::stack_push_column() that I moved and that I shouldn’t. I fixed the issue.

#10 Updated by Knödlseder Jürgen almost 3 years ago

  • Status changed from Pull request to Closed
  • % Done changed from 90 to 100

The code was merged into devel.

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