toMarginal.m

function [ni, nir, sir, kir] = toMarginal(sn, ind, state_i, phasesz, phaseshift, space_buf, space_srv, space_var) %#ok<INUSD>
% TOMARGINAL Compute marginal distributions for a specific node
%
% [NI, NIR, SIR, KIR] = TOMARGINAL(SN, IND, STATE_I, PHASESZ, PHASESHIFT, SPACE_BUF, SPACE_SRV, SPACE_VAR)
%
% @brief Extracts marginal job statistics from global state information for a specific node
%
% This function processes the global network state to compute marginal 
% distributions and job counts for a specific node, considering different
% scheduling strategies, service phases, and node types.
%
% @param sn Network structure or Network object
% @param ind Node index to extract marginal information for
% @param state_i Global state matrix or vector
% @param phasesz Vector of phase sizes for each class
% @param phaseshift Phase shift parameters for state extraction
% @param space_buf Buffer space configuration
% @param space_srv Service space configuration  
% @param space_var Variable space configuration
%
% @return ni Total jobs in node IND
% @return nir Total jobs per class in node IND [matrix: states x classes]
% @return sir Total jobs in service per class in node IND [matrix: states x classes]
% @return kir Total jobs in service per class and per phase in node IND [3D array: states x classes x phases]
 
% Copyright (c) 2012-2026, Imperial College London
% All rights reserved.
 
if ~isstruct(sn) % the input can be a Network object too
    sn=sn.getStruct();
end
 
% ind: node index
if ~sn.isstation(ind) && sn.isstateful(ind) % if stateful node
    if sn.nodetype(ind) == NodeType.Transition
        R = sn.nodeparam{ind}.nmodes;
        sir = zeros(size(state_i,1),R); % class-r jobs in service
        kir = zeros(size(state_i,1),R,max(phasesz)); % class-r jobs in service in phase k
        for r=1:R
            for k=1:phasesz(r)
                kir(:,r,k) = space_srv(:,phaseshift(r)+k);
                sir(:,r) = sir(:,r) + kir(:,r,k);
            end
        end
        nir = sir;
        ni = sum(nir);
    else
        ni = sum(state_i(1:(end-sum(sn.nvars(ind,:)))));
        nir = state_i(1:(end-sum(sn.nvars(ind,:))));
        sir = nir; % jobs in service
        kir = sir; % jobs per phase
    end
    return
end
 
R = sn.nclasses;
ist = sn.nodeToStation(ind);
isf = sn.nodeToStateful(ind);
 
if nargin < 3
    state_i = sn.state{isf};
end
 
if nargin < 5
    phasesz = sn.phasessz(ist,:);
    phaseshift = sn.phaseshift(ist,:);
end
 
isExponential = false;
if max(phasesz)==1
    isExponential = true;
end
 
if nargin < 8
    space_var = state_i(:,(end-sum(sn.nvars(ind,:))+1):end); % local variables
    space_srv = state_i(:,(end-sum(phasesz)-sum(sn.nvars(ind,:))+1):(end-sum(sn.nvars(ind,:)))); % server state
    space_buf = state_i(:,1:(end-sum(phasesz)-sum(sn.nvars(ind,:)))); % buffer state
end
 
if isExponential
    sir = space_srv;
    kir = space_srv;
else
    nir = zeros(size(state_i,1),R);
    sir = zeros(size(state_i,1),R); % class-r jobs in service
    kir = zeros(size(state_i,1),R,max(phasesz)); % class-r jobs in service in phase k
    for r=1:R
        for k=1:phasesz(r)
            kir(:,r,k) = space_srv(:,phaseshift(r)+k);
            sir(:,r) = sir(:,r) + kir(:,r,k);
        end
    end
end
 
switch sn.sched(ist)
    case SchedStrategy.INF
        for r=1:R
            nir(:,r) = sir(:,r); % class-r jobs in station
        end
    case {SchedStrategy.PS, SchedStrategy.PSPRIO}
        for r=1:R
            nir(:,r) = sir(:,r) ; % class-r jobs in station
        end
    case SchedStrategy.EXT
        for r=1:R
            nir(:,r) = Inf;
        end
    case {SchedStrategy.FCFS, SchedStrategy.FCFSPRIO, SchedStrategy.HOL}
        for r=1:R
            nir(:,r) = sir(:,r) + sum(space_buf==r,2); % class-r jobs in station
        end
    case {SchedStrategy.DPS, SchedStrategy.DPSPRIO}
        for r=1:R
            nir(:,r) = sir(:,r) ; % class-r jobs in station
        end
    case {SchedStrategy.GPS, SchedStrategy.GPSPRIO}
        for r=1:R
            nir(:,r) = sir(:,r) ; % class-r jobs in station
        end
    case {SchedStrategy.LCFS, SchedStrategy.LCFSPRIO}
        for r=1:R
            nir(:,r) = sir(:,r) + sum(space_buf==r,2); % class-r jobs in station
        end
    case {SchedStrategy.LCFSPI, SchedStrategy.LCFSPIPRIO, SchedStrategy.LCFSPR, SchedStrategy.LCFSPRPRIO}
        if length(space_buf)>1
            space_buf = space_buf(1:2:end);
            %space_bufphase = space_buf(2:2:end);
            for r=1:R
                nir(:,r) = sir(:,r) + sum(space_buf==r,2); % class-r jobs in station
            end
        else
            nir = sir;
        end
    case SchedStrategy.SIRO
        for r=1:R
            nir(:,r) = sir(:,r) + space_buf(:,r); % class-r jobs in station
        end
    case SchedStrategy.SEPT
        for r=1:R
            nir(:,r) = sir(:,r) + space_buf(:,r); % class-r jobs in station
        end
    case SchedStrategy.LEPT
        for r=1:R
            nir(:,r) = sir(:,r) + space_buf(:,r); % class-r jobs in station
        end
    case SchedStrategy.SRPT
        for r=1:R
            nir(:,r) = sir(:,r) + space_buf(:,r); % class-r jobs in station
        end
    case SchedStrategy.SRPTPRIO
        for r=1:R
            nir(:,r) = sir(:,r) + space_buf(:,r); % class-r jobs in station
        end
    otherwise % possibly other stateful nodes
        for r=1:R
            nir(:,r) = sir(:,r) ; % class-r jobs in station
        end
end
 
if sn.nodetype(ind) == NodeType.Place
    % set all service and phase data to 0
    for r=1:R
        if isnan(sn.rates(ist,r)) % if disabled station
            for k=1:phasesz(r)
                kir(:,r,k) = 0;
            end
            sir(:,r)=0;
        end
    end
else
    for r=1:R
        if isnan(sn.rates(ist,r)) % if disabled station
            nir(:,r) = 0;
            for k=1:phasesz(r)
                kir(:,r,k) = 0;
            end
            sir(:,r)=0;
        end
    end
end
 
ni = sum(nir,2); % total jobs in station
end