A first example running SMURFF

In this notebook we will run the BPMF algorithm using SMURFF, on compound-activity data.

Downloading the data files

In these examples we use ChEMBL dataset for compound-proteins activities (IC50). The IC50 values and ECFP fingerprints can be downloaded using this smurff function:



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import smurff

ic50_train, ic50_test, ecfp = smurff.load_chembl()

The resulting variables are all scipy.sparse matrices: ic50 is a sparse matrix containing interactions between chemical compounds (in the rows) and protein targets (called essays - in the columns). The matrix is already split in as train and test set.

The ecfp contains compound features. These features will not be used in this example.

Having a look at the data

The spy function in matplotlib is a handy function to plot sparsity pattern of a matrix.



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%matplotlib inline

from matplotlib.pyplot import figure, show

fig = figure()
ax = fig.add_subplot(111)
ax.spy(ic50_train.tocsr()[0:1000,:].T, markersize = 1)
show()

Running SMURFF

Finally we run make a BPMF training trainSession and call run. The run function builds the model and returns the predictions of the test data.



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trainSession = smurff.BPMFSession(
                       Ytrain     = ic50_train,
                       Ytest      = ic50_test,
                       num_latent = 16,
                       burnin     = 40,
                       nsamples   = 200,
                       verbose    = 1,
                       checkpoint_freq = 1,
                       save_freq = 1,)

predictions = trainSession.run()

We can use the calc_rmse function to calculate the RMSE.



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rmse = smurff.calc_rmse(predictions)
rmse

Plotting predictions versus actual values

Next to RMSE, we can also plot the predicted versus the actual values, to see how well the model performs.



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%matplotlib notebook

import numpy
from matplotlib.pyplot import subplots, show

y = numpy.array([ p.val for p in predictions ])
predicted = numpy.array([ p.pred_avg for p in predictions ])

fig, ax = subplots()
ax.scatter(y, predicted, edgecolors=(0, 0, 0))
ax.plot([y.min(), y.max()], [y.min(), y.max()], 'k--', lw=4)
ax.set_xlabel('Measured')
ax.set_ylabel('Predicted')
show()



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