22 lines
636 B
Mathematica
22 lines
636 B
Mathematica
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function out = vl_nntanh(x,dzdy)
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%VL_NNTANH CNN TanH hyperbolic non-linearity
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% Y = VL_NNTANH(X) computes the hyperbolic tangent non-linearity of the
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% data X. X can have an arbitrary size. The tanh is defined as follows:
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%
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% TANH(X) = (EXP(2X) - 1 )/( EXP(2x) + 1 ).
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%
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% DZDX = VL_NNTANH(X, DZDY) computes the derivative of the
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% block projected onto DZDY. DZDX and DZDY have the same
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% dimensions as X and Y respectively.
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%
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% NOTE: Matlab build-in function TANH() is used since it has extended
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% support for gpuArray
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y = tanh( x );
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if nargin <= 1 || isempty(dzdy)
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out = y;
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else
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out = dzdy .* ( 1 - y.*y );
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end
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