🌐 Mailman 3 March 2018 - scikit-learn - python.org

Custom kernel for PLS Regression (using NIPALS algorithm)
by SJ JV March 9, 2018

March 9, 2018

I have to provide a list of customized kernels to the PLSRegression api. Similar to the custom kernel support for SVM, is there support for providing kernels to PLSRegression ? Can you make this available, if not ? Thanks SV -- U

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transfer-learning for random forests
by peignier sergio March 5, 2018

March 5, 2018

Hello, I recently begun a research project on Transfer Learning with some colleagues. We would like to contribute to scikit-learn incorporating Transfer Learning functions for Random Forests as described in this recent paper: ** *https://arxiv.org/abs/1511.01258* * *Before starting we would like to ensure that no existing project is ongoing. Thanks! BR, Sergio Peignier

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help-Renaming features in Sckit-learn's CountVectorizer()
by Ranjana Girish March 5, 2018

March 5, 2018

Hai all, I have a very large pandas dataframe. Below is the sample * Id description* 1 switvch for air conditioner transformer.............. 2 control tfrmr........... 3 coling pad................. 4 DRLG machine 5 hair smothing kit............... For further process, I will contruct doument-term matrix of above data using Sckit-learn's countvectorizer *countvec = CountVectorizer()* *documenttermmatrix=countvec.fit_transform( dataset['description'])* I have to correct misspelled features in description. Replacing wrongly spelled word with correctly spelled word for large dataset is taking so much of time. So i thought of correcting features using features list in count vectorizer given by code *features_names= **countvec.get_feature_names()* *Is it possible to rename features using above list and further use it for classification process???* Thanks Ranjana

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Need help in dealing with large dataset
by CHETHAN MURALI March 5, 2018

March 5, 2018

Dear All, I am working on building a CNN model for image classification problem. As par of it I have converted all my test images to numpy array. Now when I am trying to split the array into training and test set I am getting memory error. Details are as below: X = np.load("./data/X_train.npy", mmap_mode='r') train_pct_index = int(0.8 * len(X)) X_train, X_test = X[:train_pct_index], X[train_pct_index:] X_train = X_train.reshape(X_train.shape[0], 256, 256, 3) X_train = X_train.astype('float32') -------------------------------------------------MemoryError Traceback (most recent call last)<ipython-input-46-9180807e01dc> in <module>() 2 print("Normalizing Data") 3 ----> 4 X_train = X_train.astype('float32') *More information:* *1. my python version is* python --versionPython 3.6.4 :: Anaconda custom (64-bit) *2. I am running the code in ubuntu ubuntu 16.04.* *3. I have 32GB RAM* *4. X_train.npy file that I have loaded to np.array is of size 20GB* print("X_train Shape: ", X_train.shape) X_train Shape: (85108, 256, 256, 3) I would be really glad if you can help me to overcome this problem. Regards, - Chethan

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custom loss function in RandomForestRegressor
by Thomas Evangelidis March 1, 2018

March 1, 2018

Greetings, The feature importance calculated by the RandomForest implementation is a very useful feature. I personally use it to select the best features because it is simple and fast, and then I train MLPRegressors. The limitation of this approach is that although I can control the loss function of the MLPRegressor (I have modified scikit-learn's implementation to accept an arbitrary loss function), I cannot do the same with RandomForestRegressor, and hence I have to rely on 'mse' which is not in accordance with the loss functions I use in MLPs. Today I was looking at the _criterion.pyx file: https://github.com/scikit-learn/scikit-learn/blob/master/sklearn/tree/_crit… However, the code is in Cython and I find it hard to follow. I know that for Regression the relevant class are Criterion(), RegressionCriterion(Criterion), and MSE(RegressionCriterion). My question is: is it possible to write a class that takes an arbitrary function "loss(predictions, targets)" to calculate the loss and impurity of the nodes? thanks, Thomas -- ====================================================================== Dr Thomas Evangelidis Post-doctoral Researcher CEITEC - Central European Institute of Technology Masaryk University Kamenice 5/A35/2S049, 62500 Brno, Czech Republic email: tevang(a)pharm.uoa.gr tevang3(a)gmail.com website: https://sites.google.com/site/thomasevangelidishomepage/

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