* fix cv::imwrite to allow cv::UMat and vectors of it to be written
* cv::imwrite failure handling improvements
* Unit test for regression testing imwrite support for and fix whitespace
In case of regression trees, node risk is computed as sum of squared
error. To get a meaningfull value to compare with it needs to be
normalized to the number of samples in the node (or more generally to
the sum of sample weights in this node). Otherwise the sum of squared
error is highly dependend on the number of samples in the node and
comparision with `regressionAccuracy` parameter is not very meaningful.
After normalization `node_risk` means in fact sample variance for all
samples in the node, which makes much more sence and seams to be what
was originaly intended by the code given that node risk is later used as
a split termination criteria by
```
sqrt(node.node_risk) < params.getRegressionAccuracy()
```
- Recommended compiler checks:
- GCC: CV_GCC
- Clang: CV_CLANG
- fixed problem with CMAKE_CXX_COMPILER_ID=Clang/AppleClang mess on MacOSX
Details: cmake --help-policy CMP0025
- do not declare Clang as GCC compiler
My build fails with the error:
"C:/PROGRA~1/MINGW-~1/X86_64~1.0-P/mingw64/lib/gcc/x86_64-w64-mingw32/7.2.0/include/c++/cmath:1136:11: error: '::hypot' has not been declared".
I have tried to fix it by adding "#include <cmath>" before the line "#include <Python.h>" but then the build has failed with the error:
"C:/PROGRA~1/MINGW-~1/X86_64~1.0-P/mingw64/lib/gcc/x86_64-w64-mingw32/7.2.0/include/c++/math.h:91:12:: error: 'std::_hypot' has not been declared".
Adding "#include <math.h>" allowed me to build opencv.
Arkadiusz Raj
Dmitry Kurtaev
Alexander Alekhin
ltqusst
catree
RAJKIRAN NATARAJAN
Maksim Shabunin
LaurentBerger
Tomoaki Teshima
Collen Jones
corley
codingforfun
kinchungwong
Namgoo Lee
Andrei Costinescu
Anthony Wertz