%SELECT S-function it is used to reset the Mossy fiber when its limit value is exceeded.
% [sys,x0,str,ts] = Thresh(t,x,u,flag,Uth,Ureset)
% Mossy fiber dynamic is given by the equation:
% ?_m (dU_m)/dt=-U_m (t)+RI(t)
% When the membrane potential reaches a threshold value Uthresh, the neuron fires and
% Um is reset to a value Ureset < Uthresh. The input current I(t) was determined by a
% radial basis function (RBF) of one of the sensory variables (target position or velocity).
% The RBF centers were evenly distributed across the sensory dimensions, and their
% variance were chosen to ensure small responses overlap from consecutive mossy fibers.
% Implementation in Simulink.
% 2007 Niceto Luque Sola
function [sys,x0,str,ts] = Thresh4refractarytime(t,x,u,flag,Uth,Ureset,Trefract)
%SFUNTMPL General M-file S-function template
% With M-file S-functions, you can define you own ordinary differential
% equations (ODEs), discrete system equations, and/or just about
% any type of algorithm to be used within a Simulink block diagram.
% The general form of an M-File S-function syntax is:
% [SYS,X0,STR,TS] = SFUNC(T,X,U,FLAG,P1,...,Pn)
% What is returned by SFUNC at a given point in time, T, depends on the
% value of the FLAG, the current state vector, X, and the current
% input vector, U.
% FLAG RESULT DESCRIPTION
% ----- ------ --------------------------------------------
% 0 [SIZES,X0,STR,TS] Initialization, return system sizes in SYS,
% initial state in X0, state ordering strings
% in STR, and sample times in TS.
% 1 DX Return continuous state derivatives in SYS.
% 2 DS Update discrete states SYS = X(n+1)
% 3 Y Return outputs in SYS.
% 4 TNEXT Return next time hit for variable step sample
% time in SYS.
% 5 Reserved for future (root finding).
% 9  Termination, perform any cleanup SYS=.
% The state vectors, X and X0 consists of continuous states followed
% by discrete states.
% Optional parameters, P1,...,Pn can be provided to the S-function and
% used during any FLAG operation.
% When SFUNC is called with FLAG = 0, the following information
% should be returned:
% SYS(1) = Number of continuous states.
% SYS(2) = Number of discrete states.
% SYS(3) = Number of outputs.
% SYS(4) = Number of inputs.
% Any of the first four elements in SYS can be specified
% as -1 indicating that they are dynamically sized. The
% actual length for all other flags will be equal to the
% length of the input, U.
% SYS(5) = Reserved for root finding. Must be zero.
% SYS(6) = Direct feedthrough flag (1=yes, 0=no). The s-function
% has direct feedthrough if U is used during the FLAG=3
% call. Setting this to 0 is akin to making a promise that
% U will not be used during FLAG=3. If you break the promise
% then unpredictable results will occur.
% SYS(7) = Number of sample times. This is the number of rows in TS.
% X0 = Initial state conditions or  if no states.
% STR = State ordering strings which is generally specified as .
% TS = An m-by-2 matrix containing the sample time
% (period, offset) information. Where m = number of sample
% times. The ordering of the sample times must be:
% TS = [0 0, : Continuous sample time.
% 0 1, : Continuous, but fixed in minor step
% sample time.
% PERIOD OFFSET, : Discrete sample time where
% PERIOD > 0 & OFFSET < PERIOD.
% -2 0]; : Variable step discrete sample time
% where FLAG=4 is used to get time of
% next hit.
% There can be more than one sample time providing
% they are ordered such that they are monotonically
% increasing. Only the needed sample times should be
% specified in TS. When specifying than one
% sample time, you must check for sample hits explicitly by
% seeing if
% abs(round((T-OFFSET)/PERIOD) - (T-OFFSET)/PERIOD)
% is within a specified tolerance, generally 1e-8. This
% tolerance is dependent upon your model's sampling times
% and simulation time.
% You can also specify that the sample time of the S-function
% is inherited from the driving block. For functions which
% change during minor steps, this is done by
% specifying SYS(7) = 1 and TS = [-1 0]. For functions which
% are held during minor steps, this is done by specifying
% SYS(7) = 1 and TS = [-1 1].
% Copyright 1990-2002 The MathWorks, Inc.
% $Revision: 1.18 $
% The following outlines the general structure of an S-function.
% Initialization %
% Derivatives %
% Update %
% Outputs %
% GetTimeOfNextVarHit %
% Terminate %
% Unexpected flags %
error(['Unhandled flag = ',num2str(flag)]);
% end sfuntmpl
% Return the sizes, initial conditions, and sample times for the S-function.
% call simsizes for a sizes structure, fill it in and convert it to a
% sizes array.
% Note that in this example, the values are hard coded. This is not a
% recommended practice as the characteristics of the block are typically
% defined by the S-function parameters.
sizes = simsizes;
sizes.NumContStates = 0;
sizes.NumDiscStates = 0;
sizes.DirFeedthrough = 1;
sizes.NumSampleTimes = 1; % at least one sample time is needed
sys = simsizes(sizes);
% initialize the initial conditions
x0 = ;
% str is always an empty matrix
str = ;
% initialize the array of sample times
ts = [-1 0];
% end mdlInitializeSizes
% Return the derivatives for the continuous states.
sys = ;
% end mdlDerivatives
% Handle discrete state updates, sample time hits, and major time step
sys = ;
% end mdlUpdate
% Return the block outputs.
%Limit value where reset happen
indexrefract=find(Tprevious<t & Tprevious>0.000);
% if Tprevious(i)<t && Tprevious(i)>0.0000
% end mdlOutputs
% Return the time of the next hit for this block. Note that the result is
% absolute time. Note that this function is only used when you specify a
% variable discrete-time sample time [-2 0] in the sample time array in
sampleTime = 1; % Example, set the next hit to be one second later.
sys = t + sampleTime;
% end mdlGetTimeOfNextVarHit
% Perform any end of simulation tasks.
sys = ;
% end mdlTerminate