add example for thresholds

shogun-toolbox · Nov 30, 2011 · 646ff20 · 646ff20
1 parent afa4852
commit 646ff20
Showing 1 changed file with 31 additions and 0 deletions.
diff --git a/examples/undocumented/python_modular/evaluation_thresholds_modular.py b/examples/undocumented/python_modular/evaluation_thresholds_modular.py
@@ -0,0 +1,31 @@
+parameter_list = [[1000]]
+
+def evaluation_thresholds_modular(index):
+	from modshogun import Labels, ROCEvaluation
+	import numpy
+	numpy.random.seed(17)
+	output=numpy.arange(-1,1,0.001)
+	output=(0.3*output+0.7*(numpy.random.rand(len(output))-0.5))
+	label=[-1.0]*(len(output)/2)
+	label.extend([1.0]*(len(output)/2))
+	label=numpy.array(label)
+
+	pred=Labels(output)
+	truth=Labels(label)
+
+	evaluator=ROCEvaluation()
+	evaluator.evaluate(pred, truth)
+
+	[fp,tp]=evaluator.get_ROC()
+
+	thresh=evaluator.get_thresholds()
+	b=thresh[index]
+
+	print "tpr", numpy.mean(output[label>0]>b), tp[index]
+	print "fpr", numpy.mean(output[label<0]>b), fp[index]
+
+	return tp[index],fp[index],numpy.mean(output[label>0]>b),numpy.mean(output[label<0]>b)
+
+if __name__=='__main__':
+	print 'Evaluation with Thresholds'
+	evaluation_thresholds_modular(*parameter_list[0])