Assignment with incompatible sizes fails silently (Bug #1714)

Added by Baris Demiroz almost 13 years ago. Updated almost 13 years ago.

Status:Done Start date:2012-03-25
Priority:Low Due date:
Assignee:Andrey Kamaev % Done:

0%
Category:core
Target version:2.4.0
Affected version: Operating System:
Difficulty: HW Platform:
Pull request:

Description

I had two matrices one of them with size 2x2, the other one 1x3. When I tried to assign the second one to the first row of 2x2 matrix, it neither raised an error, nor made an assignment. It took me a little while to find out the sizes are incompatible. It is better to raise an error so the errors can be caught early.

Example code to reproduce:

    Mat1f A = Mat1f::zeros(2,2);
    Mat1f B = Mat1f::ones(1,3);
    A.row(0) = B.colRange(0,3);
    cout << A << endl;

Associated revisions

Revision 8a4f1bbb
Added by Roman Donchenko over 11 years ago

Merge pull request #1714 from jet47:find-cuda-fix

Revision 104b14e0
Added by Roman Donchenko over 11 years ago

Fixed CMake warnings/bugs caused by #1670 and #1714

include() doesn't create a variable scope, so the settings of
CMAKE_MODULE_PATH and CMAKE_FIND_ROOT_PATH_MODE_* were polluting
everything included after OpenCVDetectCUDA.cmake.

Also, FindCUDA includes FindPackageHandleStandardArgs, which includes
CMakeParseArguments, which causes warnings related to policy CMP0017.
Setting it to NEW seems safe enough.

History

#1
Updated by Andrey Kamaev almost 13 years ago

It is a "feature" of C++ API: http://opencv.itseez.com/modules/core/doc/intro.html#automatic-memory-management

A.row(0) creates a temporary Mat, then = B.colRange(0,3) repoints this temporary Mat to the submat of B.
To make a real assignment you should use copyTo method:

B.colRange(0,3).copyTo(A.row(0));

This will rise an error if the sizes are incompatible.

  • Status changed from Open to Cancelled
  • Target version set to 2.4.0
  • Category set to core
  • Assignee set to Andrey Kamaev

#2
Updated by Baris Demiroz almost 13 years ago

Doing 

B.colRange(0,3).copyTo(A.row(0));
does not work either. When 'A' is displayed it is all zero matrix.
So this is still a bug. Can you reopen it?

#3
Updated by Andrey Kamaev almost 13 years ago

Sorry for fast closing, I was not aware about MS language extension which results in unexpected behavior.

The issue is completely fixed in r7625.

From now code

1B.colRange(0,3).copyTo(A.row(0));

compiles both with gcc and MS compiler and assign or throw.

However the following fragment does not throw on incompatible types. And this is intentional gotcha:

1Mat C = A.row(0);
2B.colRange(0,3).copyTo(C);

  • Status changed from Cancelled to Done
  • Target version deleted (2.4.0)

#4
Updated by Alexander Shishkov almost 13 years ago

  • Target version set to 2.4.0

Also available in: Atom PDF