export an unfitted model to ONNX - onnx

I am building an API for training models, and figured I wanted to use ONNX to send the models back and forth.
I am testing with a sklearn XGboost model, and it seems that it is a requirement to fit the model before I can export it to onnx.
I want to define a custom or standard sklearn model, convert to onnx for transport, reopen and train, save in ONNX
Is this feasable at all?
My end goal is to have an API that can accept any sklearn, tensorflow or similar model in an untrained state and then train on the server.

Onnx is used to deliver model results, including pre and post-processing or other manipulations, "in production".
The assumption is the model is already trained and you only need to "predict" (or whatever similar action) on new data.
Sound like what you need is a Python (or other) code that will receive your API calls, translate them into the appropriate models, train the models, and then, if you want to be independent from an MLOps point of view, transform the result into Onnx.

Related

Convert timm model to huggingface

I have a (PyTorch) timm ViT-B/16 model that's been pre-trained on a bunch of domain specific data. I'd like to be able to load the parameters to an equivalent model created using the huggingface transformers library for usage with multi-modal data.
Googling hasn't really helped me locate a convenience function to do the conversion. Apart from going layer by layer and manually translating the keys of the state dictionary, is there any way to do this conversion?
And in case I'm missing something, if there's an intervening layer (say a BatchNorm) that doesn't have an equivalent in either model - is the conversion still useful?

Porting pre-trained keras models and run them on IPU

I am trying to port two pre-trained keras models into the IPU machine. I managed to load and run them using IPUstrategy.scope but I dont know if i am doing it the right way. I have my pre-trained models in .h5 file format.
I load them this way:
def first_model():
model = tf.keras.models.load_model("./model1.h5")
return model
After searching your ipu.keras.models.py file I couldn't find any load methods to load my pre-trained models, and this is why i used tf.keras.models.load_model().
Then i use this code to run:
cfg=ipu.utils.create_ipu_config()
cfg=ipu.utils.auto_select_ipus(cfg, 1)
ipu.utils.configure_ipu_system(cfg)
ipu.utils.move_variable_initialization_to_cpu()
strategy = ipu.ipu_strategy.IPUStrategy()
with strategy.scope():
model = first_model()
print('compile attempt\n')
model.compile("sgd", "categorical_crossentropy", metrics=["accuracy"])
print('compilation completed\n')
print('running attempt\n')
res = model.predict(input_img)[0]
print('run completed\n')
you can see the output here:link
So i have some difficulties to understand how and if the system is working properly.
Basically the model.compile wont compile my model but when i use model.predict then the system first compiles and then is running. Why is that happening? Is there another way to run pre-trained keras models on an IPU chip?
Another question I have is if its possible to load a pre-trained keras model inside an ipu.keras.model and then use model.fit/evaluate to further train and evaluate it and then save it for future use?
One last question I have is about the compilation part of the graph. Is there a way to avoid recompilation of the graph every time i use the model.predict() in a different strategy.scope()?
I use tensorflow2.1.2 wheel
Thank you for your time
To add some context, the Graphcore TensorFlow wheel includes a port of Keras for the IPU, available as tensorflow.python.ipu.keras. You can access the API documentation for IPU Keras at this link. This module contains IPU-specific optimised replacement for TensorFlow Keras classes Model and Sequential, plus more high-performance, multi-IPU classes e.g. PipelineModel and PipelineSequential.
As per your specific issue, you are right when you mention that there are no IPU-specific ways to load pre-trained Keras models at present. I would encourage you, as you appear to have access to IPUs, to reach out to Graphcore Support. When doing so, please attach your pre-trained Keras model model1.h5 and a self-contained reproducer of your code.
Switching topic to the recompilation question: using an executable cache prevents recompilation, you can set that up with environmental variable TF_POPLAR_FLAGS='--executable_cache_path=./cache'. I'd also recommend to take a look into the following resources:
this tutorial gathers several considerations around recompilation and how to avoid it when using TensorFlow2 on the IPU.
Graphcore TensorFlow documentation here explains how to use the pre-compile mode on the IPU.

Pytorch image segmentation transfer learning

I am new in Pytorch. My question is: How do I apply transfer learning to a custom dataset? I am doing image segmentation on brain tumors. I can find examples which use U-net structure but I could not find examples using weights of the pre-trained models for a U-net image segmentation?
You could obtain pre-trained models in two ways:
Model weights or complete models shared in formats such .pt or .pth:
In this case, Saving and Loading Models is a good starting point. Copying from the tutorial there, you could load a model as
model = TheModelClass(*args, **kwargs)
model.load_state_dict(torch.load(PATH))
The other way is to load the model from torchvision. A list is available models is available at Torchvision Models. U-Net is not available yet. However, it is possible to load a pre-trained model as the encoder and write a separate decoder to form a U-Net with a pre-trained encoder.
In this case, the model object returned from the function calls shown in the API are already loaded with pretrained weights when pretrained=True.
For writing a custom dataloader, PyTorch data loaders may be a useful guide.

Using a pytorch model for inference

I am using the fastai library (fast.ai) to train an image classifier. The model created by fastai is actually a pytorch model.
type(model)
<class 'torch.nn.modules.container.Sequential'>
Now, I want to use this model from pytorch for inference. Here is my code so far:
torch.save(model,"./torch_model_v1")
the_model = torch.load("./torch_model_v1")
the_model.eval() # shows the entire network architecture
Based on the example shown here: http://pytorch.org/tutorials/beginner/data_loading_tutorial.html#sphx-glr-beginner-data-loading-tutorial-py, I understand that I need to write my own data loading class which will override some of the functions in the Dataset class. But what is not clear to me is the transformations that I need to apply at test time? In particular, how do I normalize the images at test time?
Another question: is my approach of saving and loading the model in pytorch fine? I read in the tutorial here: http://pytorch.org/docs/master/notes/serialization.html that the approach that I have used is not recommended. The reason is not clear though.
Just to clarify: the_model.eval() not only prints the architecture, but sets the model to evaluation mode.
In particular, how do I normalize the images at test time?
It depends on the model you have. For instance, for torchvision modules, you have to normalize the inputs this way.
Regarding on how to save / load models, torch.save/torch.load "saves/loads an object to a disk file."
So, if you save the_model, it will save the entire model object, including its architecture definition and some other internal aspects. If you save the_model.state_dict(), it will save a dictionary containing the model state (i.e. parameters and buffers) only. Saving the model can break the code in various ways, so the preferred method is to save and load only the model state. However, I'm not sure if fast.ai "model file" is actually a full model or the state of a model. You have to check this so you can correctly load it.

Keras: better way to implement layer-wise training model?

I'm currently learning implementing layer-wise training model with Keras. My solution is complicated and time-costing, could someone give me some suggestions to do it in a easy way? Also could someone explain the topology of Keras especially the relations among nodes.outbound_layer, nodes.inbound_layer and how did they associated with tensors: input_tensors and output_tensors? From the topology source codes on github, I'm quite confused about:
input_tensors[i] == inbound_layers[i].inbound_nodes[node_indices[i]].output_tensors[tensor_indices[i]]
Why the inbound_nodes contain output_tensors, I'm not clear about the relations among them....If I wanna remove layers in certain positions of the API model, what should I firstly remove? Also, when adding layers to some certain places, what shall I do first?
Here is my solution to a layerwise training model. I can do it on Sequential model and now trying to implement in on the API model:
To do it, I'm simply add a new layer after finish previous training and re-compile (model.compile()) and re-fit (model.fit()).
Since Keras model requires output layer, I would always add an output layer. As a result, each time when I wanna add a new layer, I have to remove the output layer then add it back. This can be done using model.pop(), in this case model has to be a keras.Sequential() model.
The Sequential() model supports many useful functions including model.add(layer). But for customised model using model API: model=Model(input=...., output=....), those pop() or add() functions are not supported and implement them takes some time and maybe not convenient.

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