Model.evaluate() takes up a lot of memory

I was stuck into the “insufficient memory” difficulty. When I checked the memory usage with the help of ‘@profile’ I found that the ‘evaluate()’ method caused a significant increment. But from my perspective, it’s just a computation progress and its return value is a 2-elements list so that it should have no effect on the memory. I’ll appreciate you if you tell me how to solve this problem, thanks!