Failure in initial objective function evaluation. FMINCON cannot continue in s function

Question

aditya deepak 2023-1-8

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1890387-failure-in-initial-objective-function-evaluation-fmincon-cannot-continue-in-s-function

评论： Matt J 2023-1-10

I am using a level 2 s function to perform fmincon and I need to limit the rate of change of output. I have stored the output using Dwork vectors. I want to create a constraint where the difference between the current output value and previous output value should be less than 20.

function ECMSsf2(block)

setup(block);

%endfunction

function setup(block)

%% Register number of input and output ports

block.NumInputPorts = 2;

block.NumOutputPorts = 3;

%% Setup functional port properties to dynamically

%% inherited.

block.SetPreCompInpPortInfoToDynamic;

block.SetPreCompOutPortInfoToDynamic;

block.InputPort(1).DirectFeedthrough = false;

%% Set block sample time to inherited

block.SampleTimes = [-1 0];

%% Set the block simStateCompliance to default (i.e., same as a built-in block)

block.SimStateCompliance = 'DefaultSimState';

%% Register methods

block.RegBlockMethod('PostPropagationSetup',@DoPostPropSetup);

block.RegBlockMethod('InitializeConditions',@InitConditions);

block.RegBlockMethod('SetInputPortSamplingMode', @SetInpPortFrameData);

block.RegBlockMethod('Outputs', @Output);

block.RegBlockMethod('Update', @Update);

function DoPostPropSetup(block)

%% Setup Dwork

block.NumDworks = 1;

block.Dwork(1).Name = 'x0';

block.Dwork(1).Dimensions = 1;

block.Dwork(1).DatatypeID = 0;

block.Dwork(1).Complexity = 'Real';

block.Dwork(1).UsedAsDiscState = true;

end

function InitConditions(block)

% Initialize Dwork

block.Dwork(1).Data = 0;

end

function SetInpPortFrameData(block, idx, fd)

block.InputPort(idx).SamplingMode = fd;

block.OutputPort(1).SamplingMode = fd;

block.OutputPort(2).SamplingMode = fd;

block.OutputPort(3).SamplingMode = fd;

end

function Output(block)

%constants initialization

Pbatt_char=5000;

SOC_min=0.2;

SOC_max=0.90;

Pfc_min=1000;

Pfc_max=10000;

Pbatt_max=17000;

%define Matrix Aeq

Aeq=[0 1 0;1 0 1];

%define Matrix beq

mu = 0.6;

beq=[(1-2*mu*((block.InputPort(2).Data-0.5*(SOC_max+SOC_min))/(SOC_max+SOC_min))); block.InputPort(1).Data];

%define boundary conditions

lb=[Pfc_min, 0, -Pbatt_char];

ub=[Pfc_max, 100, Pbatt_max];

%defining initial conditions

x0 = [0 0 0];

options = optimoptions('fmincon','Algorithm','active-set','Display','off','MaxFunctionEvaluations',1000,'MaxIterations',100);

[y,fval] = fmincon('OF_ECMS',x0,[],[],Aeq,beq,lb,ub,'Nonlinearequations',options); %#ok<*ASGLU>

Pfc=y(1); Pbatt=y(3); alpha=y(2);

block.OutPort(1).Data = Pfc;

block.OutPort(2).Data = Pbatt;

block.OutPort(3).Data = alpha;

end

function Update(block)

block.Dwork(1).Data = block.Outport(1).Data;

end

and the objective function is

function f = OF_ECMS(y(1),y(2),y(3));

f = (y(1)+y(2)*y(3));

end

and the constraints are

function [c, ceq] = Nonlinearequations(y,PFCold)

c = [];

ceq = [];

PFCold = block.Dwork(1).Data;

% Ramp constraints which are inequality constraints

c(1) = PFCold - y(1) + 20;

c(2) = y(1) - PFCold - 20;

end

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Answer 1

Matt J 2023-1-8

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1890387-failure-in-initial-objective-function-evaluation-fmincon-cannot-continue-in-s-function#answer_1144302

编辑：Matt J 2023-1-8

在 MATLAB Online 中打开

Both your objective function and constraints are linear, so you should be using linprog. In fact, you nonlinear constraints are simple bounds on y(1). So, do instead,

  lb=[Pfc_min, 0, -Pbatt_char];
  ub=[Pfc_max, 100, Pbatt_max];
  
  PFCold = block.Dwork(1).Data;
  lb(1)=max(lb(1), PFCold-20);
  ub(1)=min(ub(1), PFCold+20);
  
  
  [y,fval] = linprog([1,1,1], [],[],Aeq,beq,lb,ub);