[scikit-learn] Trying to get learning curves with custom scorer and leave one group out

[Matteo Niccoli]

My apologies, there was a typo in the code below, second example, should
read:

train_scores1, test_scores1 = validation_curve(SVC_classifier_LOWO_VC1, X,
y, "C", parm_range1, cv =logo.split(X, y, groups=groups), scoring =
'accuracy')

Everything else is correct.


On Fri, December 2, 2016 10:28 pm, Matteo Niccoli wrote:
> HI all,
>
>
> I want to plot learning curves on a trained SVM classifier, using a
> custom scorer, and using Leave One Group Out as the method of
> crossvalidation. I thought I had it figured out, but two different scorers
> - 'f1_micro' and
> 'accuracy' - will yield identical values. I am confused, is that supposed
> to be the case?
>
> Here's my code (unfortunately I cannot share the data as it is not open):
>
>
> from sklearn import svm SVC_classifier_LOWO_VC0 = svm.SVC(cache_size=800,
> class_weight=None, coef0=0.0, decision_function_shape=None, degree=3,
> gamma=0.01, kernel='rbf', max_iter=-1, probability=False, random_state=1,
> shrinking=True, tol=0.001, verbose=False) training_data =
> pd.read_csv('training_data.csv') scaler =
> preprocessing.StandardScaler().fit(X) X = scaler.transform(X)
> y = training_data['Targets'].values groups = training_data["Groups"].values
>  Fscorer = make_scorer(f1_score, average = 'micro')
> logo = LeaveOneGroupOut() parm_range0 = np.logspace(-2, 6, 9)
train_scores0,
> test_scores0 = validation_curve(SVC_classifier_LOWO_VC0, X, y, "C",
> parm_range0, cv =logo.split(X, y, groups=groups), scoring = Fscorer)
>
>
> Now, from:
> train_scores_mean0 = np.mean(train_scores0, axis=1) train_scores_std0 =
> np.std(train_scores0, axis=1) test_scores_mean0 = np.mean(test_scores0,
> axis=1) test_scores_std0 = np.std(test_scores0, axis=1) print
> test_scores_mean0 print np.amax(test_scores_mean0) print  np.logspace(-2,
> 6, 9)[test_scores_mean0.argmax(axis=0)]
>
>
> I get:
> [ 0.20257407  0.35551122  0.40791047  0.49887676  0.5021742   0.50030438
> 0.49426622  0.48066419  0.4868987 ]
> 0.502174200206
> 100.0
>
>
> If I create a new classifier, but with the same parameters, and run
> everything exactly as before, except for the scoring, e.g.:
>
> parm_range1 = np.logspace(-2, 6, 9) train_scores1, test_scores1 =
> validation_curve(SVC_classifier_LOWO_VC1, X, y, "C", parm_range1, cv
> =logo.split(X, y, groups=wells), scoring =
> 'accuracy')
> train_scores_mean1 = np.mean(train_scores1, axis=1) train_scores_std1=
> np.std(train_scores1, axis=1) test_scores_mean1 = np.mean(test_scores1,
> axis=1) test_scores_std1 = np.std(test_scores1, axis=1) print
> test_scores_mean1 print np.amax(test_scores_mean1) print  np.logspace(-2,
> 6, 9)[test_scores_mean1.argmax(axis=0)]
>
>
> I get exactly the same answer:
> [ 0.20257407  0.35551122  0.40791047  0.49887676  0.5021742   0.50030438
> 0.49426622  0.48066419  0.4868987 ]
> 0.502174200206
> 100.0
>
>
> How is that possible, am I doing something wrong, or missing something?
>
>
> Thanks
>
>
>