Sequential drug decision problems in long-term medical conditions: a case Study of Primary Hypertension Eunju Kim ba, ma, msc


FOR n = 1:N % For each time period, FOR



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FOR n = 1:N % For each time period,

FOR t = 1:T % Observe N cases.

cState = 1; % Current health state.

cStateIdx = 1; % Location in the Q-table.

fdHist = 1; % Memory variable to save the disease history.

tHist = []; % Memory variable to save the treatment history.

cProb = 1; % The probability of the current state.

% ∊-greedy action choice: by 1-(1/log(n+2)).

pn = rand(1);



IF pn < (1-(1/log(n+2))),

[nil,drug] = max(Q{t}(cState,:));



ELSE drug = randi([1,SS]); END
% Randomly generate a new event and update the disease history.

nState = randi([1,3]); fdHist = [fdHist,nState];


% Find the location in the Q-table.

[~,nStateIdx] = ismember(fdHist,SqDiz{t+1}(:,:),'rows');


% Calculate the immediate reward associated to <s,a,s’>.

[nprob,IR] = function_IPR(t,cState,drug,cProb);

% Update the value of Q. Step-size parameter alpha=(1/sqrt(n+1)).

delta = IR+DR*max(Q{t+1}(nStateIdx,:))-

Q{t}(cStateIdx,drug);

dQ = (1/sqrt(n+2))*delta;

Q{t}(cStateIdx,drug) = Q{t}(cStateIdx,drug)+dQ;

% Save the Q-variation and compute means over 100 Q-variation values.

discrepancy(mod(n,100)+1) = abs(dQ);

IF (length(discrepancy) == 100)

mdiscrepancy = [mdiscrepancy,mean(discrepancy)];

discrepancy = [];

END;
% Update the current state and the probability with the next state.

cState = fdHist(1,end);

cStateIdx = nStateIdx;

cProb = nextprob(1,nEvent);



END

END

END
% Decide the optimal solution based on the values in the Q-tables and the feasibility test.

FOR t = 1:T

FOR h = 1:size(Q{t},1)

[v,idx] = sort(Q{t}(h,:),'descend');


FOR a = 1:size(v,2)

IF The feasibility assumptions is satisfied,

Break

END

[OptV(:,:),OptSol(:,:)] = max(Q{t},[],2);



END

END

END

Figure ‎3.. Pseudo-code for the Q-learning used for the simple hypothetical case


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