While using caffe as
./build/tools/caffe train --solver=models/Handmade/solver.prototxt
caffe also gets into "phase: TEST" but I have no test data. I only want to train the parameters on my training data, so I haven't used "phase: Test" in "train.prototxt", which causes error. What should I do?
I don't know if you can completely omit the test phase but it's possible to train your model without needing a separate test set. It's also possible to prevent the solver from ever switching to the test phase.
Reuse your training data for the test phase. You can do so by duplicating your data layer and specifying it for the test phase.
To limit computations to the training phase only increase the value of test_interval in your solver definition to a number larger than your training set or, better, larger than max_iter. This prevents the solver from ever switching to the test phase.
I find it a bit odd to train a model without wanting to know how to does on a separate set of data points.
Related
I have a convolutional neural network and my input data are 10.000 images of the same object from different views (angles in 3D around the image). My network converges, but I am not sure if the network has memorized all the different angles / views or not. Since I only have one object I cannot really check test it with different data.
My training / test plot looks like this (red trainig, green test):
Since the test is lower than training I expect the network to learn all the images by heart? Even though I have 10.000 kind of different images.
First, "memorize" is not a term we apply to the learning process, since it's not exact regurgitation of prior examples.
This is a matter of your experimental process. You get to define the success criteria. Is 95% accuracy good enough for your intended application? What, to you, is good enough performance to declare success?
One way to build a more convincing argument is to make the typical third partition: besides training and test sets, save part of your data for validation. You do the training and testing as you've already done. When the model has converged, you apply it to the validation set to predict results. If that test passes your success criterion, then you have a finished model.
My apologies since my question may sound stupid question. But I am quite new in deep learning and caffe.
How can we detect how many iterations are required to fine-tune a pre-trained on our own dataset? For example, I am running fcn32 for my own data with 5 classes. When can I stop the fine-tuning process by looking at the loss and accuracy of training phase?
Many thanks
You shouldn't do it by looking at the loss or accuracy of training phase. Theoretically, the training accuracy should always be increasing (also means the training loss should always be decreasing) because you train the network to decrease the training loss. But a high training accuracy doesn't necessary mean a high test accuracy, that's what we referred as over-fitting problem. So what you need to find is a point where the accuracy of test set (or validation set if you have it) stops increasing. And you can simply do it by specifying a relatively larger number of iteration at first, then monitor the test accuracy or test loss, if the test accuracy stops increasing (or the loss stops decreasing) in consistently N iterations (or epochs), where N could be 10 or other number specified by you, then stop the training process.
The best thing to do is to track training and validation accuracy and store snapshots of the weights every k iterations. To compute validation accuracy you need to have a sparate set of held out data which you do not use for training.
Then, you can stop once the validation accuracy stops increasing or starts decreasing. This is called early stopping in the literature. Keras, for example, provides functionality for this: https://keras.io/callbacks/#earlystopping
Also, it's good practice to plot the above quantities, because it gives you important insights into the training process. See http://cs231n.github.io/neural-networks-3/#accuracy for a great illustration (not specific to early stopping).
Hope this helps
Normally you converge to a specific validation accuracy for your model. In practice you normally stop training, if the validation loss did not increase in x epochs. Depending on your epoch duration x may vary most commonly between 5 and 20.
Edit:
An epoch is one iteration over your dataset for trainig in ML terms. You do not seem to have a validation set. Normally the data is split into training and validation data so you can see how well your model performs on unseen data and made decisions about which model to take by looking at this data. You might want to take a look at http://caffe.berkeleyvision.org/gathered/examples/mnist.html to see the usage of a validation set, even though they call it test set.
I have a really sophisticated net which takes up a lot of memory on my gpu. I have found out that if I train and test my data (which is the standard case) the memory usage is as twice as high as if I do only training. Is it really necessary to test my data? Or is it just used for visualisation, i.e. to show me if my net is overfitting or sth like that?
I assume it is necessary, but I do not know the reason. My question is: How to separate training and testing? I know you can do
test_initialization: false
But if I want to test my net how would I do that afterwards?
Thanks in advance!
If you have a TEST phase in your train.prototxt, you can use a command line to test your network. You can see this link, where they mention the following command line:
# score the learned LeNet model on the validation set as defined in the
# model architeture lenet_train_test.prototxt
caffe test -model examples/mnist/lenet_train_test.prototxt -weights
examples/mnist/lenet_iter_10000.caffemodel -gpu 0 -iterations 100
You can edit it to test your network.
There is also a Python tutorial you can follow to load the trained network with a script and use it in the field. This can be manipulated to perform separate forward passes and compare the results with what you expect. I don't expect this to work completely out of the box, so you will have to try some things out.
I have a pre-trained network with which I would like to test my data. I defined the network architecture using a .prototxt and my data layer is a custom Python Layer that receives a .txt file with the path of my data and its label, preprocess it and then feed to the network.
At the end of the network, I have a custom Python layer that get the class prediction made by the net and the label (from the first layer) and print, for example, the accuracy regarding all batches.
I would like to run the network until all examples have passed through the net.
However, while searching for the command to test a network, I've found:
caffe test -model architecture.prototxt -weights model.caffemodel -gpu 0 -iterations 100
If I don't set the -iterations, it uses the default value (50).
Does any of you know a way to run caffe test without setting the number of iterations?
Thank you very much for your help!
No, Caffe does not have a facility to detect that it has run exactly one epoch (use each input vector exactly once). You could write a validation input routine to do that, but Caffe expects you to supply the quantity. This way, you can generate easily comparable results for a variety of validation data sets. However, I agree that it would be a convenient feature.
The lack of this feature might be related to its lack for training and the interstitial testing.
In training, we tune the hyper-parameters to get the most accurate model for a given application. As it turns out, this is more closely dependent on TOTAL_NUM than on the number of epochs (given a sufficiently large training set).
With a fixed training set, we often graph accuracy (y-axis) against epochs (x-axis), because that gives tractable results as we adjust batch size. However, if we cut the size of the training set in half, the most comparable graph would scale on TOTAL_NUM rather than the epoch number.
Also, by restricting the size of the test set, we avoid long waits for that feedback during training. For instance, in training against the ImageNet data set (1.2M images), I generally test with around 1000 images, typically no more than 5 times per epoch.
I'm working with Caffe and am interested in comparing my training and test errors in order to determine if my network is overfitting or underfitting. However, I can't seem to figure out how to have Caffe report training error. It will show training loss (the value of the loss function computed over the batch), but this is not useful in determining if the network is overfitting/underfitting. Is there a straightforward way to do this?
I'm using the Python interface to Caffe (pycaffe). If I could get access to the raw training set somehow, I could just put batches through with forward passes and evaluate the results. But, I can't seem to figure out how to access more than the currently-processing batch of training data. Is this possible? My data is in a LMDB format.
In the train_val.prototxt file change the source in the TEST phase to point to the training LMDB database (by default it points to the validation LMDB database) and then run this command:
$ ./build/tools/caffe test -solver models/bvlc_reference_caffenet/solver.prototxt -weights models/bvlc_reference_caffenet/<caffenet_train_iter>.caffemodel -gpu 0