tflite_runtime, but easier.
Project description
tflit 🔥
Because WTH tflite_runtime
?
interpreter.invoke()
?
interpreter.set_tensor(input_details[0]['index'], X)
?
Having to select a platform-specific url from here?
Uh no. certainly not 🔥.
What this does:
- Detects your platform + Python version so you don't have to pick the right url and you can add
tflite_runtime
as a dependency without having to pick a single platform to support. - Creates a familiar
keras
-like interface for models, so you can dotflit.Model(path).predict(X)
without ever having to think about tensor indexes or three step predictions, or batching.
Install
pip install tflit
Usage
I tried to provide an interface as similar to Keras as possible.
import tflit
model = tflit.Model('path/to/model.tflite')
model.summary() # prints input and output details
print(model.input_shape) # (10, 30) - a single input
print(model.output_shape) # [(5, 2), (1, 2)] - two outputs
print(model.dtype) # 'float32'
# *see notes below
print(model.input_names) # may not preserve names (based on how you export)
print(model.output_names) # doesn't preserve names atm
# predict over batches of outputs.
y_pred = model.predict(np.random.randn(32, 10, 30))
# predict single output at a time
y_pred = model.predict_batch(np.random.randn(1, 10, 30))
Dark Ages
Just for reference, this is how I used to do it:
def load_tflite_model_function(model_path, **kw):
import tflite_runtime.interpreter as tflite
compute = prepare_model_function(tflite.Interpreter(model_path), **kw)
compute.model_path = model_path
return compute
def prepare_model_function(model, verbose=False):
# assumes a single input and output
in_dets = model.get_input_details()[0]
out_dets = model.get_output_details()[0]
model.allocate_tensors()
def compute(x):
# set inputs
model.set_tensor(in_dets['index'], X.astype(in_dets['dtype']))
# compute outputs
model.invoke()
# get outputs
return model.get_tensor(out_dets['index'])
if verbose:
print('-- Input details --')
print(in_dets, '\n')
print('-- Output details --')
print(out_dets, '\n')
# set input and output shapes so they're easily accessible
compute.input_shape = in_dets['shape'][1:]
compute.output_shape = out_dets['shape'][1:]
return compute
This was cleaner than the code that I factored it out from, but it is still unnecessarily complex and I got tired after copying it over to my 3rd project. This also doesn't handle things like multiple inputs/outputs or batching.
Notes
-
I was having trouble getting tflite_runtime to install as a dependency in
setup.py
so right now, it's just installing on first run if it's not already installed. I'll probably fix that at some point... but I have other things that I need to be doing and this is working atm. Hopefully tensorflow will just start deploying to pypi and this will all be resolved. Not sure what's going on there... -
It's possible that
tflite_runtime
may not have a build for your system. Check this link to verify. -
There's a bug with the current
tflite
converter where it doesn't copy over the input and output names.However, if you do this when you're exporting, the input names will be saved:
converter = tf.lite.TFLiteConverter.from_keras_model(model) converter.experimental_new_converter = True # <<< this tflite_model = converter.convert()
But still no luck with the output names :/. To be clear, this is a tensorflow issue and I have no control over this.
-
I intended to have a
model.set_batch_size
method to change the batch size at runtime, but it doesn't currently work because tflite freaks out about there being an increased tensor size (it doesn't know how to broadcast). This is also a tensorflow issue.For the time being, we just compute one batch at a time and concatenate them at the end. If the model's fixed batch size doesn't divide evenly, it will throw an error. By default, tflite converts
None
batch sizes to1
so most of the time it won't be a problem. To compute a single frame, it is more efficient to usemodel.predict_batch(X)
directly.
I would love to get both of these resolved, but they are out of my control and I don't really have the bandwidth or the urgent need to have these resolved.
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