CvANN_MLP default parameters

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Transferred from http://code.opencv.org/issues/3583

|| Canberk Baci on 2014-02-27 21:57
|| Priority: Low
|| Affected: 2.4.8 (latest release)
|| Category: ml
|| Tracker: Bug
|| Difficulty: Easy
|| PR: 
|| Platform: Any / Any

CvANN_MLP default parameters

Constructor parameters alpha and beta (fparam1 and fparam2) should be default 1, not 0. Current default values lead to an undefined behavior. Related issue @SO: http://stackoverflow.com/questions/21988502/opencv-neural-network-sigmoid-output#comment33482666_21988502

History

Canberk Baci on 2014-02-28 10:07

@master branch *modules/ml/include/opencv2/ml.hpp lines 1905, 1911, 1921, 1925.* https://github.com/Itseez/opencv/blob/master/modules/ml/include/opencv2/ml.hpp#L1905

current constructor and the create method:

_CvANN_MLP(const CvMat* layerSizes, int activateFunc=CvANN_MLP::SIGMOID_SYM, double fparam1=0, double fparam2=0);_

leads sigmoid output *f(x) = 0*, since fparam1 and fparam2 are both 0. Sigmoid function is documented at http://docs.opencv.org/modules/ml/doc/neural_networks.html

*fparam1* and *fparam2* should be updated to *1* to verify the documented default sigmoid output.

Dinar Ahmatnurov on 2014-03-04 10:51

Maria what do you think?
-   Assignee set to Maria Dimashova
-   Status changed from New to Open
-   Category set to ml