Mercurial > hg > tvii
changeset 23:f34110e28a0a
[logistic regression] we have a working cost function
| author | Jeff Hammel <k0scist@gmail.com> |
|---|---|
| date | Mon, 04 Sep 2017 09:14:25 -0700 |
| parents | 3713c6733990 |
| children | 89f46435a9e2 |
| files | tests/test_logistic_regression.py tvii/logistic_regression.py |
| diffstat | 2 files changed, 5 insertions(+), 5 deletions(-) [+] |
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--- a/tests/test_logistic_regression.py Mon Sep 04 08:59:52 2017 -0700 +++ b/tests/test_logistic_regression.py Mon Sep 04 09:14:25 2017 -0700 @@ -21,7 +21,7 @@ expected_cost = 6.000064773192205 cost = logistic_regression.cost_function(w, b, X, Y) - print cost + assert abs(cost - expected_cost) < 1e-6 if __name__ == '__main__': unittest.main()
--- a/tvii/logistic_regression.py Mon Sep 04 08:59:52 2017 -0700 +++ b/tvii/logistic_regression.py Mon Sep 04 09:14:25 2017 -0700 @@ -44,7 +44,7 @@ """ m = X.shape[1] - A = w.T*X # compute activation + A = sigmoid(w.T*X + b)# compute activation def cost_function(w, b, X, Y): @@ -58,9 +58,9 @@ """ m = X.shape[1] - A = w.T*X - cost = Y*np.log(A) + (1 - Y)*np.log(1 - A) - return (1./m)*cost + A = sigmoid(np.dot(w.T, X) + b) + cost = np.sum(Y*np.log(A) + (1 - Y)*np.log(1 - A)) + return (-1./m)*cost def logistic_regression(_):