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https://github.com/anitan0925/ResFGB
Functional gradient boosting based on residual network perception
https://github.com/anitan0925/ResFGB
boosting classification deep-learning functional-gradient-boosting
Last synced: about 14 hours ago
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Functional gradient boosting based on residual network perception
- Host: GitHub
- URL: https://github.com/anitan0925/ResFGB
- Owner: anitan0925
- License: mit
- Created: 2018-02-18T17:13:32.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2020-09-15T07:51:13.000Z (about 4 years ago)
- Last Synced: 2024-08-02T03:02:35.624Z (3 months ago)
- Topics: boosting, classification, deep-learning, functional-gradient-boosting
- Language: Python
- Homepage:
- Size: 56.6 KB
- Stars: 29
- Watchers: 3
- Forks: 5
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-gradient-boosting-papers - [Code
README
Remark: The code is updated from the ICML version. The ICML version corresponds to a commit on May 25, 2018.
# ResFGB
This is a Theano(>=1.0.0) implementation of "[Functional gradient boosting based on residual network perception](https://arxiv.org/abs/1802.09031)".
ResFGB is a functional gradient boosting method for learning a resnet-like deep neural network for non-linear classification problems. The model is composed of a linear classifier such as logistic regression and support vector machine, and a feature extraction.
In each iteration, these components are trained by alternate optimization, that is, a linear classifier is trained to classify obtained samples through a feature extraction and this extraction map is updated by stacking a resnet-type layer to move samples along the direction of increasing the linear separability. We finally obtain a highly non-linear classifier forming a residual network.
## Usage
A simple pseudocode is provided below.
__Note__: `(X,Y)`: training data, `(Xv,Yv)`: validation data, `(Xt,Yt)`: test data.
These are numpy arrays.
`n_data`: the number of training data, `input_dim`: dimension of the input space, `n_class`: the number of classes.
__A label set should be an integer sequence starting with zero.__
```python
from resfgb.models import ResFGB, get_hyperparams
hparams = get_hyperparams( n_data, input_dim, n_class )
model = ResFGB( **hparams )
best_iters,_ ,_ = model.fit( X, Y, Xv, Yv, use_best_iter=True )
train_loss, train_acc = model.evaluate( X, Y )
print( 'train_loss: {0}, train_acc: {1}'.format(train_loss, train_acc) )
test_loss, test_acc = model.evaluate( Xt, Yt )
print( 'test_loss : {0}, test_acc : {1}'.format(test_loss, test_acc) )
```
See `examples/sample_resfgb.py` for more detail.
## Hyperparameters
Hyperparameters of ResFGB are mainly divided three types: the first is for learning a linear classifier, the second is for learning a multi-layer network as a resblock, and the other is for the functional gradient method.
The hyperparameters are listed below.
'Default' is a value set by the function `resfgb.models.get_hyperparams`.
`input_dim` and `n_class` stand for the dimension of the input space and the number of classes, respectively.
### For the linear model
- `shape`[default=(input\_dim, n\_class)]
- Shape of the linear model, which __should not be changed__.
- `wr`[default=1/n_data]
- L2-regularization parameter.
- `bias`[default=True]
- Flag for whether to include bias term or not.
- `eta`[default=1e-2]
- Learning rate for Nesterov's momentum method.
- `momentum`[default=0.9]
- Momentum parameter for Nesterov's momentum method.
- `minibatch_size`[default=100]
- Minibatch size to compute stochastic gradients.
- `max_epoch`[default=100]
- The number of epochs for learning a linear model.
- `tune_eta`[default=True]
- Flag for whether to tune learning rate or not.
- `scale`[default=1.0]
- Positive number by which a tuned learning rate is multiplied.
- `eval_iters`[default=1000]
- The number of iterations in a trial for tuning learning rate.
- `early_stop`[default=10]
- When the training loss does not improve while this number of epochs, the training is stopped.
### For the resblock
- `shape`[default=(input_dim,100,100,100,100,input_dim)]
- Shape of the multi-layer perceptron. __Dimensions of the input and last layer should set to input_dim__.
- `wr`[default=1/n_data]
- L2-regularization parameter.
- `eta`[default=1e-2]
- Learning rate for Nesterov's momentum method.
- `momentum`[default=0.9]
- Momentum parameter for Nesterov's momentum method.
- `minibatch_size`[default=100]
- Minibatch size to compute stochastic gradients.
- `max_epoch`[default=50]
- The number of epochs for learning a linear model.
- `tune_eta`[default=True]
- Flag for whether to tune learning rate or not.
- `scale`[default=1.0]
- Positive number by which a tuned learning rate is multiplied.
- `eval_iters`[default=1000]
- The number of iterations in a trial for tuning learning rate.
- `early_stop`[default=10]
- When the training loss does not improve while this number of epochs, the training is stopped.
### For the functional gradient method
- `model_type`[default='logistic']
- Type of the linear model: 'logistic' or 'smooth_hinge'.
- `model_hparams`[default=model_hparams]
- Dictionary of the hyperparameter for the linear model.
- `resblock_hparams`[default=resblock_hparams]
- Dictionary of the hyperparameter for the resblock.
- `fg_eta`[default=1e-1]
- Learning rate used in the functional gradient method.
- `max_iters`[default=30
- The number of iterations of the functional gradient method, which corresponds to the depth of an obtained network.
- `seed`[default=1]
- Random seed used in the method.