Quantization tool in tensorflow

[liuhantao9]

You are using quantize_graph tool to quantize the model.
https://github.com/tensorflow/tensorflow/tree/master/tensorflow/contrib/lite
On this website, they are suggesting freeze the graph using .pb and .ckpt, then convert it to .tflite.
I think freeze_graph tool can also generate a quantized model.
Do you know what is the difference?
Where is the .ckpt file for darkflow?