setReward.m

function self = setReward(self, name, rewardFn)
% SETREWARD Define a reward function on the network for CTMC analysis
%
% SELF = SETREWARD(SELF, NAME, REWARDFN)
%
% NAME     - String identifier for the reward
% REWARDFN - Function handle @(state, sn) -> double
%            state: state vector (same format as stateSpace rows)
%            sn: NetworkStruct for accessing rates, parameters
%
% Multiple rewards can be defined by calling setReward multiple times
% with different names. Use clearRewards() to remove all rewards.
%
% Example:
%   model.setReward('qlen', @(state, sn) state(2));  % Jobs at position 2
%   model.setReward('throughput', @(state, sn) state(2) * sn.rates(2,1));
%
% Copyright (c) 2012-2026, Imperial College London
% All rights reserved.
 
if ~ischar(name) && ~isstring(name)
    error('Reward name must be a string');
end
if ~isa(rewardFn, 'function_handle')
    error('Reward function must be a function handle @(state, sn) -> double');
end
 
% Initialize reward cell array if needed
if isempty(self.sn)
    self.sn = NetworkStruct();
end
if ~isfield(self.sn, 'reward') || isempty(self.sn.reward)
    self.sn.reward = {};
end
 
% Check if reward with this name already exists and update it
name = char(name);
found = false;
for i = 1:length(self.sn.reward)
    if strcmp(self.sn.reward{i}.name, name)
        self.sn.reward{i}.fn = rewardFn;
        found = true;
        break;
    end
end
 
% Add new reward if not found
if ~found
    reward.name = name;
    reward.fn = rewardFn;
    reward.type = 'state';
    self.sn.reward{end+1} = reward;
end
 
end