94 lines
3.4 KiB
Python
94 lines
3.4 KiB
Python
import random
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import subprocess
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import tempfile
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from os.path import join, exists
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from os import remove
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from subprocess import PIPE, STDOUT
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import numpy as np
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from sklearn.base import BaseEstimator, ClassifierMixin
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from sklearn.datasets import dump_svmlight_file
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class SVMperf(BaseEstimator, ClassifierMixin):
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# losses with their respective codes in svm_perf implementation
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valid_losses = {'01':0, 'f1':1, 'kld':12, 'nkld':13, 'q':22, 'qacc':23, 'qf1':24, 'qgm':25, 'mae':26, 'mrae':27}
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def __init__(self, svmperf_base, C=0.01, verbose=False, loss='01'):
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self.svmperf_base = svmperf_base
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self.C = C
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self.verbose = verbose
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self.loss = loss
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def set_params(self, **parameters):
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assert list(parameters.keys()) == ['C'], 'currently, only the C parameter is supported'
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self.C = parameters['C']
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def fit(self, X, y):
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assert self.loss in SVMperf.valid_losses, \
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f'unsupported loss {self.loss}, valid ones are {list(SVMperf.valid_losses.keys())}'
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self.svmperf_learn = join(self.svmperf_base, 'svm_perf_learn')
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self.svmperf_classify = join(self.svmperf_base, 'svm_perf_classify')
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self.loss_cmd = '-w 3 -l ' + str(self.valid_losses[self.loss])
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self.c_cmd = '-c ' + str(self.C)
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self.classes_ = sorted(np.unique(y))
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self.n_classes_ = len(self.classes_)
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local_random = random.Random()
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# this would allow to run parallel instances of predict
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random_code = '-'.join(str(local_random.randint(0,1000000)) for _ in range(5))
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self.tmpdir = tempfile.TemporaryDirectory(suffix=random_code)
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self.model = join(self.tmpdir.name, 'model-'+random_code)
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traindat = join(self.tmpdir.name, f'train-{random_code}.dat')
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dump_svmlight_file(X, y, traindat, zero_based=False)
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cmd = ' '.join([self.svmperf_learn, self.c_cmd, self.loss_cmd, traindat, self.model])
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if self.verbose:
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print('[Running]', cmd)
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p = subprocess.run(cmd.split(), stdout=PIPE, stderr=STDOUT)
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remove(traindat)
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if self.verbose:
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print(p.stdout.decode('utf-8'))
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return self
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def predict(self, X):
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confidence_scores = self.decision_function(X)
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predictions = (confidence_scores > 0) * 1
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return predictions
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def decision_function(self, X, y=None):
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assert hasattr(self, 'tmpdir'), 'predict called before fit'
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assert self.tmpdir is not None, 'model directory corrupted'
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assert exists(self.model), 'model not found'
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if y is None:
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y = np.zeros(X.shape[0])
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# in order to allow for parallel runs of predict, a random code is assigned
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local_random = random.Random()
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random_code = '-'.join(str(local_random.randint(0, 1000000)) for _ in range(5))
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predictions_path = join(self.tmpdir.name, 'predictions'+random_code+'.dat')
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testdat = join(self.tmpdir.name, 'test'+random_code+'.dat')
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dump_svmlight_file(X, y, testdat, zero_based=False)
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cmd = ' '.join([self.svmperf_classify, testdat, self.model, predictions_path])
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if self.verbose:
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print('[Running]', cmd)
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p = subprocess.run(cmd.split(), stdout=PIPE, stderr=STDOUT)
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if self.verbose:
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print(p.stdout.decode('utf-8'))
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scores = np.loadtxt(predictions_path)
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remove(testdat)
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remove(predictions_path)
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return scores
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