How to save a Trainer?

[aiLiwensong]

Now, I have trained my DIY net. How can I save it, so that I can use it again sometimes?

trainer = BackpropTrainer(fnn,dataset=trndata,verbose=True)

save up trainer.

[NuclearManD]

I would use pickle. Although I have only lightly used PyBrain, pickle should almost always work. I have an example with your code:
import pickle
(rest of your imports and code before pickling)
trainer = BackpropTrainer(fnn,dataset=trndata,verbose=True)
f=open("your_file.pd",'wb')
pickle.dump(trainer,f)
f.close()
This will save your trainer. To load it:
import pickle,BackpropTrainer
f=open("your_file.pd",'rb')
trainer=pickle.load(f)
f.close()
In order to load the trainer the BackpropTrainer will have to be imported before unpickling. I haven't tested this code, but it should work.

Note that the "pickle module is not secure against erroneous or maliciously constructed data."(Python Docs)
If you are only saving it for yourself it's fine, but be careful otherwise. See the Python Docs or SO

Of course, it would be very nice to have a serialization exclusively for your trainer, but I have only lightly used Pybrain and know of no serialization. Pickle is what I would use for most of the code I write.

[aiLiwensong]

Thanks for your answer. I'll try! @NuclearManD