How to get : per activation tensor dynamic range?

I run the sampleINT8API on win10,cuda10,cudnn7.5,tensorRT5.1.5.It works well.
This sample, sampleINT8API, performs INT8 inference without using the INT8 calibrator; using the user provided per activation tensor dynamic range.
But i want to know how to get per activation tensor dynamic range named:resnet50_per_tensor_dynamic_range.txt?