www.gusucode.com > simbio 案例源码程序 matlab代码 > simbio/CreateARateRuleForAConstantRateOfChangeExample.m
%% Create a Rate Rule for a Constant Rate of Change % This example shows how to increase the amount or % concentration of a species by a constant value using the zero-order rate % rule. For example, suppose species |x| increases by a constant rate |k|. % The rate of change is: % % $$dx/dt=k$$ % % Set the initial amount of species |x| to 2, and the value of parameter % |k| to 1. Use the following commands to set up a SimBiology model % accordingly and simulate it. % Copyright 2015 The MathWorks, Inc. m = sbiomodel('m'); c = addcompartment(m,'comp'); s = addspecies(m,'x','InitialAmount',2); p = addparameter(m,'k','Value',1); r = addrule(m,'x = k','RuleType','rate'); [t,sd,species] = sbiosimulate(m); plot(t,sd); legend(species) xlabel('Time'); ylabel('Species Amount'); %% % Alternatively, you could model a constant increase in a species using the % Mass Action reaction |null| -> |x| with the forward rate constant |k|. clear m = sbiomodel('m'); c = addcompartment(m,'comp'); s = addspecies(m,'x','InitialAmount',2); r = addreaction(m,'null -> x'); kl = addkineticlaw(r,'MassAction'); p = addparameter(kl,'k','Value',1); kl.ParameterVariableNames = 'k'; [t,sd,species] = sbiosimulate(m); plot(t,sd); legend(species) xlabel('Time'); ylabel('Species Amount');