From the files:
QN_fltvec.h - qn_sigmoid_vf_vf(...)
QN_fltvec.cc - qn_fe_sigmoid_vf_vf(...)
QN_fltvec.cc - qn_fe_sigmoid_f_f(...)
we can see that the sigmoid function used in the hidden layer is different from the sigmoid function used in the output layer.
In the hidden layer, the sigmoid function is:
f(x)=1/(1+exp(-x))
In the output layer the sigmoid function is:
f(x)=tanh(s.a*b+c)
QN_fltvec.h - qn_sigmoid_vf_vf(...)
QN_fltvec.cc - qn_fe_sigmoid_vf_vf(...)
QN_fltvec.cc - qn_fe_sigmoid_f_f(...)
we can see that the sigmoid function used in the hidden layer is different from the sigmoid function used in the output layer.
In the hidden layer, the sigmoid function is:
f(x)=1/(1+exp(-x))
In the output layer the sigmoid function is:
f(x)=tanh(s.a*b+c)
It's the same!
ReplyDeleteThe second one is the provided "sigmoid" kernel function i n SVMLight!!!