cvTrace           231 modules/calib3d/test/test_fundam.cpp         tr = (cvTrace(&matR).val[0] - 1.)*0.5;
cvTrace          1362 modules/core/include/opencv2/core/core_c.h CVAPI(CvScalar) cvTrace( const CvArr* mat );
cvTrace           451 modules/core/test/test_math.cpp     test_mat[OUTPUT][0].at<Scalar>(0,0) = cvTrace(test_array[INPUT][0]);