Function: mod(gradient[0](sqrt(square(numbers("per") if numbers("xxr") > numbers('xry') else numbers('yxr')) if numbers("per") > numbers('yxr') if numbers("per") > numbers("xxr") else numbers('xry') else numbers('yxr'))), sqrt(numbers('xry') if numbers("per") > numbers("xxr") else numbers('yxr') if numbers("per") > numbers('yxr') else square(numbers('xry') if numbers("xxr") > numbers("per") else numbers('yxr'))))
