completeSymm function
CompleteSymm copies the lower or the upper half of a square matrix to its another half.
For further details, please see: https://docs.opencv.org/4.x/d2/de8/group__core__array.html#ga6847337c0c55769e115a70e0f011b5ca
Implementation
Mat completeSymm(InputOutputArray m, {bool lowerToUpper = false}) {
cvRun(() => cffi.Mat_CompleteSymm(m.ref, lowerToUpper));
return m;
}