How can I create a custom weighted ResampleInstance in mlr? It is possible to specify weights in the train function or in a task description. I need to create custom weights for a time series for every resampling instance.
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I have been looking for certain features in the HuggingFace transformer Trainer object (in particular Seq2SeqTrainer) and would like to know whether they exist and if so, how to implement them, or whether I would have to write my own training loop to enable them.
I am looking to apply Curriculum Learning to my training strategy, as well as evaluating the model at regular intervals, and therefore would like to enable the following
choose in which order the model sees training samples at each epoch (it seems that the data passed onto the train_dataset argument are automatically shuffled by some internal code, and even if I managed to stop that, I would still need to pass differently ordered data at different epochs, as I may want to start training the model from easy samples for a few epochs, and then pass a random shuffle of all data for later epochs)
run custom evaluation at integer multiples of a fix number of steps. The standard compute_metrics argument of the Trainer takes a function to which the predictions and labels are passed* and the user can decide how to generate the metrics given these. However I'd like a finer level of control, for example changing the maximum sequence length for the tokenizer when doing the evaluation, as opposed to when doing training, which would require me including some explicit evaluation code inside compute_metrics which needs to access the trained model and the data from disk.
Can these two points be achieved by using the Trainer on a multi-GPU machine, or would I have to write my own training loop?
*The function often looks something like this and I'm not sure it would work with the Trainer if it doesn't have this configuration
def compute_metrics(eval_pred):
predictions, labels = eval_pred
...
You can pass custom functions to compute metrics in the training arguments
I build a LSTM to forecast Precipitation, but it doesn't work well.
My code is very simple and data is very short only contains 720 points.
i use MinMaxScale to scale the data.
this is my code, seq_len = 12
model = Sequential([
layers.LSTM(2, input_shape=(SEQ_LEN, 1),
layers.Dense(1)])
my data is like this
and the output compares with true value like this
I use adam and mae loss function, epoch=10
is it underfitting? or is this simple net can't do this work?
r2_score is no more than 0.55
please tell me how to adjust it. thanks
there are so many options;
first of all it would be better to define the optimized window size by changing the periods of the sequences
The second option would be changing the batch-size of the dataset
Change optimizer into SGD cause of few datapoints and before training model define the best values for learning rate by setting Learning Rate Schedule callback
Try another model architecture with convolution layers and etc
Sometimes it would be a trick to help model performance by setting lambda layer after the last layer to scale up values cause of lstm default activation function is tanh.
I am trying to implement a model for binary classification problem. Up to now, I was using softmax function (at the output layer) together with torch.NLLLoss function to calculate the loss. However, now I want to use the sigmoid function (instead of softmax) at the output layer. If I do that, should I also change the loss function (to BCELoss or binary_cross_entropy) or may I still use torch.NLLLoss function ?
If you use sigmoid function, then you can only do binary classification. It's not possible to do a multi-class classification. The reason for this is because sigmoid function always returns a value in the range between 0 and 1. So, for instance one can threshold the value at 0.5 and separate (or classify) it into two classes based on the obtained values.
Regarding the objective function NLLLoss - Negative Log Likelihood Loss. It just learns the data distribution. So, it's not a problem as long as that what you're trying to achieve during training.
I would like to modify the ImageNet caffe model as described bellow:
As the input channel number for temporal nets is different from that
of spatial nets (20 vs. 3), we average the ImageNet model filters of
first layer across the channel, and then copy the average results 20
times as the initialization of temporal nets.
My question is how can I achive the above results? How can I open the caffe model to be able to do those changes to it?
I read the net surgery tutorial but it doesn't cover the procedure needed.
Thank you for your assistance!
AMayer
The Net Surgery tutorial should give you the basics you need to cover this. But let me explain the steps you need to do in more detail:
Prepare the .prototxt network architectures: You need two files: the existing ImageNet .prototxt file, and your new temporal network architecture. You should make all layers except the first convolutional layers identical in both networks, including the names of the layers. That way, you can use the ImageNet .caffemodel file to initialize the weights automatically.
As the first conv layer has a different size, you have to give it a different name in your .prototxt file than it has in the ImageNet file. Otherwise, Caffe will try to initialize this layer with the existing weights too, which will fail as they have different shapes. (This is what happens in the edit to your question.) Just name it e.g. conv1b and change all references to that layer accordingly.
Load the ImageNet network for testing, so you can extract the parameters from the model file:
net = caffe.Net('imagenet.prototxt', 'imagenet.caffemodel', caffe.TEST)
Extract the weights from this loaded model.
conv_1_weights = old_net.params['conv1'][0].data
conv_1_biases = old_net.params['conv1'][1].data
Average the weights across the channels:
conv_av_weights = np.mean(conv_1_weights, axis=1, keepdims=True)
Load your new network together with the old .caffemodel file, as all layers except for the first layer directly use the weights from ImageNet:
new_net = caffe.Net('new_network.prototxt', 'imagenet.caffemodel', caffe.TEST)
Assign your calculated average weights to the new network
new_net.params['conv1b'][0].data[...] = conv_av_weights
new_net.params['conv1b'][1].data[...] = conv_1_biases
Save your weights to a new .caffemodel file:
new_net.save('new_weights.caffemodel')
I need to create a specific custom waveform for an oscillator for use with Web Audio API.
I have a Javascript function to output the desired waveform (calculating a y between -1 and 1 for any given x), and the plotted result looks like this:
However the Web Audio API documentation only lets you create custom wavetables based on harmonic tables via the createPeriodicWave function, which can then be used to configure a custom oscillator via setPeriodicWave. Is there a generic technique that can be used to compute the harmonic tables based on my waveform function?
A DFT (or FFT) with a length of exactly one period of your custom waveform will produce a harmonic table. Just low-pass filter and sample your waveform 2^N times, and feed that to a generic library FFT. (Choose a large enough 2^N to be at least more than 2X the low-pass filter's or your waveform's intrinsic highest frequency content). The magnitudes of the FFT's resulting complex bins will be your harmonic power levels.