# Assigning different upper and lower bounds to function input variables when calling the function during optimization

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MaYang Long on 18 Aug 2020
Answered: Alan Weiss on 11 Jun 2021
I am using the PSO to optimize the RMSE of the computed and real energy consumption.
I called the objective function inside the PSO code
CostFunction = @ energy_demand; % Objective Function/Fitness function
and defined the lower and upper bounds for x1,x2,x3,x4,x5,x6 as:
VarMin = [0.8,0.8,1,0.3,0.1,0.1]; % Lower Bound of Decision Variables
VarMax = [1,1,10,0.7,0.5,0.5]; % Upper Bound of Decision Variables
I assumed MATLAB would pick the upper and lower bounds sequentially, but I keep getting the error:
Not enough input arguments.
Error in energy_demand (line 114)
Qlong =((Ta + 273.15).^4 - (To + 273.15).^4) * x1 * x2 * As * sigma;
Error in PSO (line 58)
particle(i).Cost = CostFunction(particle(i).Position);
Error in pso1 (line 25)
out = PSO(problem, params);
The function am trying to minimize as shown below:
function RMSE = energy_demand(x1,x2,x3,x4,x5,x6)
%% greenhouse environmental parameters
environmental_input_parameters = xlsread('day and night-time environmental inputs.xlsx','T2:Z10141');
Qreal = Qmeasured(:,2);
Ta = environmental_input_parameters(:,1); % interior temperature
slope = environmental_input_parameters(:,2); % dTa/dt
To = environmental_input_parameters(:,3); % exterior temperature
Rgo = environmental_input_parameters(:,4); % global radiation
t = environmental_input_parameters(:,5); % time series
%% Physical Constants
rho = 1.225; %Air Density in kg.m^-3
Cp = 1006.43; %specific heat capacity of air in J·kg^-1·K^-1
%% Greenhouse Physical Dimensions
Vol = 16315.517 ; % Greenhouse Volume in V/m^-3
As = 5079.9263; % surface area of the greenhouse in m^2
Ag = 3393.324; % greenhouse ground surface area in m^2
%% Thermal Model
Qlong =((Ta + 273.15).^4 - (To + 273.15).^4) * x1 * x2 * As * sigma;
%% Heat exchanged between cover and the exterior of the greenhouse
Qcover = (Ta - To) * As * x3 * x4;
%% Heat Flux of Air
Qair = slope * Vol * rho * Cp;
Qsolar = Rgo * As * x5 * x6;
%% Computed greenhouse energy consumption
Qcomputed = Qair + Qlong + Qcover - Qsolar;
alpha = sum((Qcomputed(:) - Qreal(:)).^2);
N = size((Qcomputed(:)),1);
RMSE = sqrt(alpha./N);
end
muhammad hamza on 11 Jun 2021
Same Issue im trying to minimize my objective function for boost converter which im contolling with FOPID.I need to set limits for each of 5 parameters of FOPID i need to find.

Alan Weiss on 11 Jun 2021
You need to write your function of one variable, say x = [x1,x2,x3,x4,x5]. For example,
function RMSE = energy_demand(x) % Here x has 5 components
Alan Weiss
MATLAB mathematical toolbox documentation

R2020a

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