This issue , caused by the non-convexity of error functions in neural networks , was long thought to be a major drawback .
Yann LeCun et al. argue that in many practical problems , it is not .
This issue , caused by the non-convexity of error functions in neural networks , was long thought to be a major drawback , but Yann LeCun et al. argue that in many practical problems , it is not .