OSError unable to create file - invalid argument

Question

I am using Python and Keras on top of Tensorflow to train my neural networks. When I switched from Ubuntu 16.04 to Windows 10, my model could not be saved anymore when I run the following:

filepath = "checkpoint-"+str(f)+model_type+"-"+optimizer_name+"-{epoch:02d}-{loss:.3f}.hdf5"
checkpoint = ModelCheckpoint(filepath, monitor='loss', verbose=1, save_best_only=True, mode='min')
callbacks_list = [checkpoint]

and later on:

model.fit(X, y,
      batch_size=128,
      epochs=1,
      shuffle=False,
      callbacks=callbacks_list)

I get this Error:

OSError: Unable to create file (Unable to open file: name = 'checkpoint-<_io.textiowrapper name='data/swing-projects100-raw/many-chunks/log-gamma-f3.txt' mode='a' encoding='cp1252'>2l128-adam-0.001-{epoch:02d}-{loss:.3f}.h5', errno = 22, error message = 'invalid argument', flags = 13, o_flags = 302)

I have Keras 2.0.8 and h5py 2.7.0 installed via conda.

I tried

filepath = "checkpoint-"+str(f)+model_type+"-"+optimizer_name+"-{epoch:02d}-{loss:.3f}.hdf5"

with open(filepath, "w") as f:
  f.write("Test.")

and got a similar error:

OSError: [Errno 22] Invalid argument: "checkpoint-<_io.TextIOWrapper name='data/swing-projects100-raw/many-chunks/log-gamma-f3.txt' mode='a' encoding='cp1252'>2L128-Adam-0.001-{epoch:02d}-{loss:.3f}.hdf5"

i'd suggest trying to save any simple text file with that filepath: f=open(filepath,'w') — maz
stackoverflow.com/questions/25584124/… suggests that filepath is an invalid filename. If you'd like help determining how to make filepath into a valid filename, please add the value of filepath that is resulting in the error to the question. — Seth Difley
@SethDifley You can see the value of filepath in my question before the first and the second error message. My path is a relative one and I don't know what's wrong with it. — AIpeter
@AIpeter don't you want to be calling .format on that string to put some values in? Braces and colons etc... are valid characters for common linux file systems, so you'll literally getting a file containing "{epoch:02d}" in its name - on Windows - those are not valid characters for a filename.. — Jon Clements♦

AIpeter AIpeter · Accepted Answer · 2017-09-10T14:50:20

When I removed str(f) from the filepath, it worked. f is an Integer and I don't know why it caused the error, but removing it from the string solved my problem.

Let me know if you know exactly why.

OSError unable to create file - invalid argument

3 Answers