Neural Network Toolbox |
Hyperbolic tangent sigmoid transfer function
Graph and Symbol
Syntax
Description
tansig is a transfer function. Transfer functions calculate a layer's output from its net input.
and returns each element of N
squashed between -1 and 1.
tansig(code)
return useful information for each code
string:
tansig is named after the hyperbolic tangent, which has the same shape. However, tanh
may be more accurate and is recommended for applications that require the hyperbolic tangent.
Examples
Here is the code to create a plot of the tansig transfer function.
Network Use
You can create a standard network that uses tansig by calling newff
or newcf
.
To change a network so a layer uses tansig, set net.layers{i,j}.transferFcn
to 'tansig
'.
In either case, call sim
to simulate the network with tansig. See newff
or newcf
for simulation examples.
Algorithm
tansig(N)
calculates its output according to:
This is mathematically equivalent to tanh(N)
. It differs in that it runs faster than the MATLAB® implementation of tanh
, but the results can have very small numerical differences. This function is a good trade off for neural networks, where speed is important and the exact shape of the transfer function is not.
See Also
References
Vogl, T. P., J.K. Mangis, A.K. Rigler, W.T. Zink, and D.L. Alkon, "Accelerating the convergence of the backpropagation method," Biological Cybernetics, vol. 59, pp. 257-263, 1988.
sumsqr | train |
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