also add a sampling/inference section

README.md

@@ -173,6 +173,19 @@ Thou hast no right, no right, but to be sold.
 
 Whoa there, GPT, entering some dark place over there. I didn't really tune the hyperparameters in the config too much, feel free to try!
 
+## sampling / inference
+
+Use the script `sample.py` to sample either from pre-trained GPT-2 models released by OpenAI, or from a model you trained yourself. For example, here is a way to sample from the largest available `gpt2-xl` model:
+
+```
+$ python sample.py \
+    --init_from=gpt2-xl \
+    --start="What is the answer to life, the universe, and everything?" \
+    --num_samples=5 --max_new_tokens=100
+```
+
+If you'd like to sample from a model you trained, use the `--out_dir` to point the code appropriately. You can also prompt the model with some text from a file, e.g. `$ python sample.py --start=FILE:prompt.txt`.
+
 ## efficiency notes
 
 For simple model benchmarking and profiling, `bench.py` might be useful. It's identical to what happens in the meat of the training loop of `train.py`, but omits much of the other complexities.