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Diffstat (limited to 'sourcecodes/bnt-master/netlab3.3/glmfwd.m')
| -rw-r--r-- | sourcecodes/bnt-master/netlab3.3/glmfwd.m | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/sourcecodes/bnt-master/netlab3.3/glmfwd.m b/sourcecodes/bnt-master/netlab3.3/glmfwd.m new file mode 100644 index 00000000..5a9519cd --- /dev/null +++ b/sourcecodes/bnt-master/netlab3.3/glmfwd.m @@ -0,0 +1,62 @@ +function [y, a] = glmfwd(net, x) +%GLMFWD Forward propagation through generalized linear model. +% +% Description +% Y = GLMFWD(NET, X) takes a generalized linear model data structure +% NET together with a matrix X of input vectors, and forward propagates +% the inputs through the network to generate a matrix Y of output +% vectors. Each row of X corresponds to one input vector and each row +% of Y corresponds to one output vector. +% +% [Y, A] = GLMFWD(NET, X) also returns a matrix A giving the summed +% inputs to each output unit, where each row corresponds to one +% pattern. +% +% See also +% GLM, GLMPAK, GLMUNPAK, GLMERR, GLMGRAD +% + +% Copyright (c) Ian T Nabney (1996-2001) + +% Check arguments for consistency +errstring = consist(net, 'glm', x); +if ~isempty(errstring); + error(errstring); +end + +ndata = size(x, 1); + +a = x*net.w1 + ones(ndata, 1)*net.b1; + +switch net.outfn + + case 'linear' % Linear outputs + y = a; + + case 'logistic' % Logistic outputs + % Prevent overflow and underflow: use same bounds as glmerr + % Ensure that log(1-y) is computable: need exp(a) > eps + maxcut = -log(eps); + % Ensure that log(y) is computable + mincut = -log(1/realmin - 1); + a = min(a, maxcut); + a = max(a, mincut); + y = 1./(1 + exp(-a)); + + case 'softmax' % Softmax outputs + nout = size(a,2); + % Prevent overflow and underflow: use same bounds as glmerr + % Ensure that sum(exp(a), 2) does not overflow + maxcut = log(realmax) - log(nout); + % Ensure that exp(a) > 0 + mincut = log(realmin); + a = min(a, maxcut); + a = max(a, mincut); + temp = exp(a); + y = temp./(sum(temp, 2)*ones(1,nout)); + % Ensure that log(y) is computable + y(y<realmin) = realmin; + + otherwise + error(['Unknown activation function ', net.outfn]); +end |
