Neural Network Toolbox™

Positive linear transfer function

Graph and Symbol

Syntax

• A = poslin(N,FP)
  dA_dN = poslin('dn',N,A,FP)
  info = poslin(code)
  

Description

poslin is a neural transfer function. Transfer functions calculate a layer's output from its net input.

poslin(N,FP) takes N and optional function parameters,

N	S x Q matrix of net input (column) vectors
FP	Struct of function parameters (ignored)

and returns A, the S x Q matrix of N's elements clipped to [0, inf].

poslin('dn',N,A,FP) returns the S x Q derivative of A with respect to N. If A or FP is not supplied or is set to [], FP reverts to the default parameters, and A is calculated from N.

poslin('name') returns the name of this function.

poslin('output',FP) returns the [min max] output range.

poslin('active',FP) returns the [min max] active range.

poslin('fullderiv') returns 1 or 0, depending on whether dA_dN is S x S x Q or S x Q.

poslin('fpnames') returns the names of the function parameters.

poslin('fpdefaults') returns the default function parameters.

Examples

Here is the code to create a plot of the poslin transfer function.

• n = -5:0.1:5;
  a = poslin(n);
  plot(n,a)
  

Assign this transfer function to layer i of a network.

• net.layers{i}.transferFcn = 'poslin';
  

Network Use

To change a network so that a layer uses poslin, set net.layers{i}.transferFcn to 'poslin'.

Call sim to simulate the network with poslin.

Algorithm

The transfer function poslin returns the output n if n is greater than or equal to zero and 0 if n is less than or equal to zero.

• poslin(n) = n, if n >= 0
            = 0, if n <= 0
  

See Also

sim, purelin, satlin, satlins

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