System Information

• OpenCV version: 4.8.0
• Operating System: macOS 13.3.1 (ARM64) / Ubuntu 20.04.4 (x86_64)
• Compiler: Apple clang version 14.0.3 / g++ (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0

Detailed description

Even this (1+0)/2 gives different result on macOS and Linux:

cv::Mat A = cv::Mat::ones(3, 3, CV_8UC1);
cv::Mat B = cv::Mat::zeros(3, 3, CV_8UC1);
cv::Mat mean = (A + B) / 2;
std::cout << "A = \n" << A << std::endl;
std::cout << "B = \n" << B << std::endl;
std::cout << "(A+B)/2 = \n" << mean << std::endl;

Steps to reproduce

Write this code:

cv::Mat A = cv::Mat::ones(3, 3, CV_8UC1);
cv::Mat B = cv::Mat::zeros(3, 3, CV_8UC1);
cv::Mat mean = (A + B) / 2;
std::cout << "A = \n" << A << std::endl;
std::cout << "B = \n" << B << std::endl;
std::cout << "(A+B)/2 = \n" << mean << std::endl;

On macOS:

A =
[  1,   1,   1;
   1,   1,   1;
   1,   1,   1]
B =
[  0,   0,   0;
   0,   0,   0;
   0,   0,   0]
(A+B)/2 =
[  1,   1,   1;
   1,   1,   1;
   1,   1,   0]

On Linux:

A =
[  1,   1,   1;
   1,   1,   1;
   1,   1,   1]
B =
[  0,   0,   0;
   0,   0,   0;
   0,   0,   0]
(A+B)/2 =
[  0,   0,   0;
   0,   0,   0;
   0,   0,   0]

Issue submission checklist

• I report the issue, it's not a question
• I checked the problem with documentation, FAQ, open issues, forum.opencv.org, Stack Overflow, etc and have not found any solution
• I updated to the latest OpenCV version and the issue is still there
• There is reproducer code and related data files (videos, images, onnx, etc)