equation: X/Y=P
Increase Y by an increment of 1 until gives an output equal or less than P.
Example:
X=21
Y=4
P=3
equation: 21/4=5.25
GOAL: increment Y unitl it gives an output less than or equal to P.equation: X/Y=P
Increase Y by an increment of 1 until gives an output equal or less than P.
Example:
X=21
Y=4
P=3
equation: 21/4=5.25
GOAL: increment Y unitl it gives an output less than or equal to P. equation: X/Y=P
Increase Y by an increment of 1 until gives an output equal or less than P.
Example:
X=21
Y=4
P=3
equation: 21/4=5.25
GOAL: increment Y unitl it gives an output less than or equal to P. if loop, for loop, if else, if else statement MATLAB Answers — New Questions

​

I am doing integration using MATLAB’s symbolic toolbox. I have many functions of my independent variable, z. This is my code, with numbers changed and the problem simplified. I have F1 print at the end just so I can see what the function resolves to.
l = 50;
a = 10;
W = 1200;
syms Q(z);
Q(z) = 1200 + 56*z – 2.5*z^2;

R = – int(Q(z), [0 l]) + W;
syms F1(z) F2(z) F3(z);
F1(z) = simplify(- int(Q(z), [0 z]) – R,"IgnoreAnalyticConstraints",true);

F1
Even with simplify and "IgnoreAnalyticConstraints" being set to true, F1 is in the form "73900/3 – (z*(- 5*z^2 + 168*z + 7200))/6" instead of az^3/b + cz^2/d + ez/f + g, the fully simplified method. vpa just puts all fractions in numeric form, and eval doesn’t really do anything. What am I missing, as I know that there should be some method to this simple operation of simplifying a polynomial.I am doing integration using MATLAB’s symbolic toolbox. I have many functions of my independent variable, z. This is my code, with numbers changed and the problem simplified. I have F1 print at the end just so I can see what the function resolves to.
l = 50;
a = 10;
W = 1200;
syms Q(z);
Q(z) = 1200 + 56*z – 2.5*z^2;

R = – int(Q(z), [0 l]) + W;
syms F1(z) F2(z) F3(z);
F1(z) = simplify(- int(Q(z), [0 z]) – R,"IgnoreAnalyticConstraints",true);

F1
Even with simplify and "IgnoreAnalyticConstraints" being set to true, F1 is in the form "73900/3 – (z*(- 5*z^2 + 168*z + 7200))/6" instead of az^3/b + cz^2/d + ez/f + g, the fully simplified method. vpa just puts all fractions in numeric form, and eval doesn’t really do anything. What am I missing, as I know that there should be some method to this simple operation of simplifying a polynomial. I am doing integration using MATLAB’s symbolic toolbox. I have many functions of my independent variable, z. This is my code, with numbers changed and the problem simplified. I have F1 print at the end just so I can see what the function resolves to.
l = 50;
a = 10;
W = 1200;
syms Q(z);
Q(z) = 1200 + 56*z – 2.5*z^2;

R = – int(Q(z), [0 l]) + W;
syms F1(z) F2(z) F3(z);
F1(z) = simplify(- int(Q(z), [0 z]) – R,"IgnoreAnalyticConstraints",true);

F1
Even with simplify and "IgnoreAnalyticConstraints" being set to true, F1 is in the form "73900/3 – (z*(- 5*z^2 + 168*z + 7200))/6" instead of az^3/b + cz^2/d + ez/f + g, the fully simplified method. vpa just puts all fractions in numeric form, and eval doesn’t really do anything. What am I missing, as I know that there should be some method to this simple operation of simplifying a polynomial. symbolic, function MATLAB Answers — New Questions

​

Hola, Buenos días.
Estoy intentando instalar las Toolbox Simscape, y Simscape Electrical. Todo va bien hasta que al momento de descargar e instalar las Toolbox aparece el siguiente error.

Estoy usando MATLAB R2024aHola, Buenos días.
Estoy intentando instalar las Toolbox Simscape, y Simscape Electrical. Todo va bien hasta que al momento de descargar e instalar las Toolbox aparece el siguiente error.

Estoy usando MATLAB R2024a Hola, Buenos días.
Estoy intentando instalar las Toolbox Simscape, y Simscape Electrical. Todo va bien hasta que al momento de descargar e instalar las Toolbox aparece el siguiente error.

Estoy usando MATLAB R2024a error, addon, toolbox MATLAB Answers — New Questions

​

I’m trying to run a program that needs to access the "wget" the command as follows:

[result, cmdout] = system(‘wget -h’);
Do you have any suggestions to get it working in Linux?I’m trying to run a program that needs to access the "wget" the command as follows:

[result, cmdout] = system(‘wget -h’);
Do you have any suggestions to get it working in Linux? I’m trying to run a program that needs to access the "wget" the command as follows:

[result, cmdout] = system(‘wget -h’);
Do you have any suggestions to get it working in Linux? wget, websave, url, download MATLAB Answers — New Questions

​

Hello,
I am trying to built a Simulink function which keeps record of the statistics of the system by using array of classes. However, I can not generate an array of class in Simulink. I realize that I should instantiate an array in Simulink but how can I instantiate a class?
arrivedArray(3, 65536) = queueInfo;
analysisArray(3, 65536) = queueInfo;
In the picture above, queueInfo is my class. This two lines return with the following error.
Code generation requires variable arrivedArray to be fully defined before subscribing it.
By the way, this is the suggested method by Matlab for creating an array of class but somehow it doesn’t work. Later I’ve tried this one:
persistent arrivedArray
if isempty(arrivedArray)
arrivedArray(3, 655336) = queueInfo;
end
persistent analysisArray
if isempty(analysisArray)
analysisArray(3, 65536) = queueInfo;
end

But it doesn’t work either. The error İs:
Persistent variable ‘arrivedArray’ must be assigned before it is used. The only exception is a check using ‘isempty(arrivedArray)’ that can be performed prior to assignment.

I understand the error but have no idea how to fix it. A constructor did not help me too. Here is my class structure:
1
classdef transactionInfo
properties
tag = uint16(0);
arrivalTime = uint64(0);
departureTime = uint64(0);
end
methods
function obj = transactionInfo(v)
if nargin > 0
obj.tag = uint16(v);
obj.arrivalTime = uint64(v);
obj.departureTime = uint64(v);
end
end
end
end

2
classdef queueInfo < transactionInfo
properties
length = uint16(0);
queueID = uint8(0);
delay = uint64(0);
end
methods
function obj = queueInfo(v)
if nargin > 0
obj.length = uint16(v);
obj.queueID = uint8(v);
obj.delay = uint64(v);
end
end
end
end
Does anyone know how to fix this issue?
Note: There might be some obvious errors in my class structures, I am kind of new to OOP. Every suggestion is welcomed.Hello,
I am trying to built a Simulink function which keeps record of the statistics of the system by using array of classes. However, I can not generate an array of class in Simulink. I realize that I should instantiate an array in Simulink but how can I instantiate a class?
arrivedArray(3, 65536) = queueInfo;
analysisArray(3, 65536) = queueInfo;
In the picture above, queueInfo is my class. This two lines return with the following error.
Code generation requires variable arrivedArray to be fully defined before subscribing it.
By the way, this is the suggested method by Matlab for creating an array of class but somehow it doesn’t work. Later I’ve tried this one:
persistent arrivedArray
if isempty(arrivedArray)
arrivedArray(3, 655336) = queueInfo;
end
persistent analysisArray
if isempty(analysisArray)
analysisArray(3, 65536) = queueInfo;
end

But it doesn’t work either. The error İs:
Persistent variable ‘arrivedArray’ must be assigned before it is used. The only exception is a check using ‘isempty(arrivedArray)’ that can be performed prior to assignment.

I understand the error but have no idea how to fix it. A constructor did not help me too. Here is my class structure:
1
classdef transactionInfo
properties
tag = uint16(0);
arrivalTime = uint64(0);
departureTime = uint64(0);
end
methods
function obj = transactionInfo(v)
if nargin > 0
obj.tag = uint16(v);
obj.arrivalTime = uint64(v);
obj.departureTime = uint64(v);
end
end
end
end

2
classdef queueInfo < transactionInfo
properties
length = uint16(0);
queueID = uint8(0);
delay = uint64(0);
end
methods
function obj = queueInfo(v)
if nargin > 0
obj.length = uint16(v);
obj.queueID = uint8(v);
obj.delay = uint64(v);
end
end
end
end
Does anyone know how to fix this issue?
Note: There might be some obvious errors in my class structures, I am kind of new to OOP. Every suggestion is welcomed. Hello,
I am trying to built a Simulink function which keeps record of the statistics of the system by using array of classes. However, I can not generate an array of class in Simulink. I realize that I should instantiate an array in Simulink but how can I instantiate a class?
arrivedArray(3, 65536) = queueInfo;
analysisArray(3, 65536) = queueInfo;
In the picture above, queueInfo is my class. This two lines return with the following error.
Code generation requires variable arrivedArray to be fully defined before subscribing it.
By the way, this is the suggested method by Matlab for creating an array of class but somehow it doesn’t work. Later I’ve tried this one:
persistent arrivedArray
if isempty(arrivedArray)
arrivedArray(3, 655336) = queueInfo;
end
persistent analysisArray
if isempty(analysisArray)
analysisArray(3, 65536) = queueInfo;
end

But it doesn’t work either. The error İs:
Persistent variable ‘arrivedArray’ must be assigned before it is used. The only exception is a check using ‘isempty(arrivedArray)’ that can be performed prior to assignment.

I understand the error but have no idea how to fix it. A constructor did not help me too. Here is my class structure:
1
classdef transactionInfo
properties
tag = uint16(0);
arrivalTime = uint64(0);
departureTime = uint64(0);
end
methods
function obj = transactionInfo(v)
if nargin > 0
obj.tag = uint16(v);
obj.arrivalTime = uint64(v);
obj.departureTime = uint64(v);
end
end
end
end

2
classdef queueInfo < transactionInfo
properties
length = uint16(0);
queueID = uint8(0);
delay = uint64(0);
end
methods
function obj = queueInfo(v)
if nargin > 0
obj.length = uint16(v);
obj.queueID = uint8(v);
obj.delay = uint64(v);
end
end
end
end
Does anyone know how to fix this issue?
Note: There might be some obvious errors in my class structures, I am kind of new to OOP. Every suggestion is welcomed. simulink, class, code generation MATLAB Answers — New Questions

​

I define a sparse identity matrix, using the SPEYE command as follows:

A = speye(5)

and receive the following output:

A =

(1,1) 1

(2,2) 1

(3,3) 1

(4,4) 1

(5,5) 1

I would like to write the non-zero elements as well as the row and column information corresponding to the non-zero elements to a text file.I define a sparse identity matrix, using the SPEYE command as follows:

A = speye(5)

and receive the following output:

A =

(1,1) 1

(2,2) 1

(3,3) 1

(4,4) 1

(5,5) 1

I would like to write the non-zero elements as well as the row and column information corresponding to the non-zero elements to a text file. I define a sparse identity matrix, using the SPEYE command as follows:

A = speye(5)

and receive the following output:

A =

(1,1) 1

(2,2) 1

(3,3) 1

(4,4) 1

(5,5) 1

I would like to write the non-zero elements as well as the row and column information corresponding to the non-zero elements to a text file.  MATLAB Answers — New Questions

​

I’m using Matlab/Simulink 2018b and my model is not runnable. The following error appears: The output of ‘path of chart XYZ’ cannot be logged because this block is a Simulink function within Stateflow or a MATLAB Function block. Even though no signal is logged. I don’t know how to localize the issue. Befor puschen the model to the lib it was working fine. How can I fix the issue?I’m using Matlab/Simulink 2018b and my model is not runnable. The following error appears: The output of ‘path of chart XYZ’ cannot be logged because this block is a Simulink function within Stateflow or a MATLAB Function block. Even though no signal is logged. I don’t know how to localize the issue. Befor puschen the model to the lib it was working fine. How can I fix the issue? I’m using Matlab/Simulink 2018b and my model is not runnable. The following error appears: The output of ‘path of chart XYZ’ cannot be logged because this block is a Simulink function within Stateflow or a MATLAB Function block. Even though no signal is logged. I don’t know how to localize the issue. Befor puschen the model to the lib it was working fine. How can I fix the issue? output cannot be logged MATLAB Answers — New Questions

​

I am attempting to plot stictly horizontal freestream flow using fcontour and the Symbolic Math toolbox. A few days ago I was able to successfully achieve this with the code below. However, starting last night whenever I run the script the "symbolic method" produces vertical contour lines that indicate stricty vertical freestram flow. I have gone back to the original code to ensure nothing I changed in the script had an impact, but the issue still remains. I have included an image of the incorrect plot (from the symbolic method) vs. the correct plot (from the numerical method) to better illustrate the problem. I would love some guidance on what to try and fix this strange issue.

clear
clc
% use the symbolic method to create the stream function for freestream flow
% and plot it
syms xs ys
Uval = 1;
Vval = 0;
psi_fs = Uval*ys – Vval*xs;
figure(4)
fcontour(psi_fs,[-3 3 -5 5],’k’); %’k’ makes all the lines black
% use the numerical method to create the stream function for freestream
% flow and plot it
xlocs = [-3:.1:3]; % you can use linspace for this
ylocs = [-3:.1:3];
% make the grid of points x horizontal, y vertical
[xmat,ymat] = meshgrid(xlocs,ylocs);
psi_vals_fs = Uval*ymat – Vval*xmat;
figure(5)
contour(xmat, ymat, psi_vals_fs,’k’) % ‘k’ makes all the lines blackI am attempting to plot stictly horizontal freestream flow using fcontour and the Symbolic Math toolbox. A few days ago I was able to successfully achieve this with the code below. However, starting last night whenever I run the script the "symbolic method" produces vertical contour lines that indicate stricty vertical freestram flow. I have gone back to the original code to ensure nothing I changed in the script had an impact, but the issue still remains. I have included an image of the incorrect plot (from the symbolic method) vs. the correct plot (from the numerical method) to better illustrate the problem. I would love some guidance on what to try and fix this strange issue.

clear
clc
% use the symbolic method to create the stream function for freestream flow
% and plot it
syms xs ys
Uval = 1;
Vval = 0;
psi_fs = Uval*ys – Vval*xs;
figure(4)
fcontour(psi_fs,[-3 3 -5 5],’k’); %’k’ makes all the lines black
% use the numerical method to create the stream function for freestream
% flow and plot it
xlocs = [-3:.1:3]; % you can use linspace for this
ylocs = [-3:.1:3];
% make the grid of points x horizontal, y vertical
[xmat,ymat] = meshgrid(xlocs,ylocs);
psi_vals_fs = Uval*ymat – Vval*xmat;
figure(5)
contour(xmat, ymat, psi_vals_fs,’k’) % ‘k’ makes all the lines black I am attempting to plot stictly horizontal freestream flow using fcontour and the Symbolic Math toolbox. A few days ago I was able to successfully achieve this with the code below. However, starting last night whenever I run the script the "symbolic method" produces vertical contour lines that indicate stricty vertical freestram flow. I have gone back to the original code to ensure nothing I changed in the script had an impact, but the issue still remains. I have included an image of the incorrect plot (from the symbolic method) vs. the correct plot (from the numerical method) to better illustrate the problem. I would love some guidance on what to try and fix this strange issue.

clear
clc
% use the symbolic method to create the stream function for freestream flow
% and plot it
syms xs ys
Uval = 1;
Vval = 0;
psi_fs = Uval*ys – Vval*xs;
figure(4)
fcontour(psi_fs,[-3 3 -5 5],’k’); %’k’ makes all the lines black
% use the numerical method to create the stream function for freestream
% flow and plot it
xlocs = [-3:.1:3]; % you can use linspace for this
ylocs = [-3:.1:3];
% make the grid of points x horizontal, y vertical
[xmat,ymat] = meshgrid(xlocs,ylocs);
psi_vals_fs = Uval*ymat – Vval*xmat;
figure(5)
contour(xmat, ymat, psi_vals_fs,’k’) % ‘k’ makes all the lines black fcontour, symbolic MATLAB Answers — New Questions

​

I have a constitutive model with 4 parameters to fit to experimental stress vs strain data. Before implementing the GA, I tried lsqnonlin (with and without multistart), but one of the main problems is that the algorithm often tends to assign bound values to the optimised parameters. To the first parameter, which is larger than the others, it assigns the upper bound, to the second and third it assigns the lower bounds. Plotting the best individuals over time, it appears that the ga spans little between the solutions, and the optimisation seems to be biased towards the first parameter.
I am using the uniaxial model proposed by Dong, and have rechecked the correctness of the model form several times. Below is the main containing the ga and my error function. Any help is welcome, thank you

%CHANGE LINE 3 TO SELECT THE PATCH
%CHANGE LINES 9 AND 10 TO SELECT THE SPECIMEN
clc; clear all;close all;
load ("data_11122.mat"); % change lot number if necessary
clearvars -except data

%Model requires lambda= x/x0 instead of epsilon: calculate lambda
% from exp data and store in data struct

stress=data(6).stress; %change index to change dogbone if necessary
stress=stress/max(stress);
strain=data(6).strain; %change index to change dogbone if necessary
p_initial=[50 25 5 .5]*10e-3;
a0=[1 0 0];
%vincoli su zeta imposti da dong ( zeta tra 0 e 1 )
lb=[0 0 0 0]; %% AGGIUSTA UNITA DIN MISURA
ub=[650 98 35 1];

%ottimizzazione non lineare con metodo least square ( like Dong )
options = optimoptions(‘ga’, ‘Display’, ‘iter’, ‘PopulationSize’, 100, ‘MaxGenerations’, 200, ‘UseParallel’, true,’NonlinearConstraintAlgorithm’,’penalty’,’PlotFcn’,’gaplotbestindiv’,’InitialPopulationMatrix’,p_initial);
nvars=4;
[p_opt, fval, exitflag, output] = ga(@(p)(error_function(p, strain, stress)), nvars, [], [], [], [], lb, ub, [], options);

%check plot e ricostruzione del modello con i parametri ottimizzati
c = p_opt(1); % c
k1 = p_opt(2); % k1
k2 = p_opt(3); % k2
zeta = p_opt(4); % zeta
for i=1:length(strain)

sigma_calculated(i)=c*(strain(i)^2) + 2*strain(i)^2*k1*((strain(i)^2-1)*(i-zeta)^2*exp(k2*(strain(i)^2-1)^2*(1-zeta)^2));

end

% for i=1:length(strain)
% f = [strain(i) 0 0; %deformation gradient for each value of strain
% 0 1/sqrt(strain(i)) 0;
% 0 0 1/sqrt(strain(i))];
% C = f .* f’; % Calcola il tensore di Cauchy-Green
% prodot = a0 .* a0′;
% I4 = sum(sum(C .* prodot)); % calcolo invariante di C
% I = eye(3); % Matrice identità
%
% sigma= f*c*I*f’ + 2*f*(k1 * (1 – zeta)^2 * (I4 – 1) * (exp(k2 * ((1 – zeta) * (I4 – 1))^2)) * prodot)*f’;
%
% sigma_calculated(i)= sigma(1,1); %componente xx
% end

figure()
plot (strain,stress);
hold on
plot(strain, sigma_calculated,’r’);
legend (‘experimental’, ‘model’,’Location’, ‘northwest’);

function error = error_function(p,strain,stress)

sigma_calculated = zeros(length(strain), 1);

for i = 2:length(strain) %avoiding first value=0;

% f = [strain(i) 0 0; %deformation gradient
% 0 1/sqrt(strain(i)) 0;
% 0 0 1/sqrt(strain(i))];
% C = f .* f’; % tensore di Cauchy-Green
% prodot = a0 .* a0′;
% I4 = a0′ .* C .* a0; % calcolo IV invariante di C
% I = eye(3);
%
% sigma= f*p(1)*I*f’ + 2*f*(p(2) * (1 – p(4))^2 * (I4 – 1) * (exp(p(3) * ((1 – p(4)) * (I4 – 1))^2)) * prodot)*f’;
%
%
% sigma_calculated(i)= sigma(1,1); %componente xx
sigma_calculated(i)=p(1)*(strain(i)^2) + 2*strain(i)^2*p(2)*((strain(i)^2-1)*(i-p(4))^2*exp(p(3)*(strain(i)^2-1)^2*(1-p(4))^2));

end

error= sum((sigma_calculated-stress).^2) ; %/sum(stress).^2; % Somma dei quadrati delle differenze
%aggiungere normalizzazione rispetto allo stress( guardare script marta calcolo error )
endI have a constitutive model with 4 parameters to fit to experimental stress vs strain data. Before implementing the GA, I tried lsqnonlin (with and without multistart), but one of the main problems is that the algorithm often tends to assign bound values to the optimised parameters. To the first parameter, which is larger than the others, it assigns the upper bound, to the second and third it assigns the lower bounds. Plotting the best individuals over time, it appears that the ga spans little between the solutions, and the optimisation seems to be biased towards the first parameter.
I am using the uniaxial model proposed by Dong, and have rechecked the correctness of the model form several times. Below is the main containing the ga and my error function. Any help is welcome, thank you

%CHANGE LINE 3 TO SELECT THE PATCH
%CHANGE LINES 9 AND 10 TO SELECT THE SPECIMEN
clc; clear all;close all;
load ("data_11122.mat"); % change lot number if necessary
clearvars -except data

%Model requires lambda= x/x0 instead of epsilon: calculate lambda
% from exp data and store in data struct

stress=data(6).stress; %change index to change dogbone if necessary
stress=stress/max(stress);
strain=data(6).strain; %change index to change dogbone if necessary
p_initial=[50 25 5 .5]*10e-3;
a0=[1 0 0];
%vincoli su zeta imposti da dong ( zeta tra 0 e 1 )
lb=[0 0 0 0]; %% AGGIUSTA UNITA DIN MISURA
ub=[650 98 35 1];

%ottimizzazione non lineare con metodo least square ( like Dong )
options = optimoptions(‘ga’, ‘Display’, ‘iter’, ‘PopulationSize’, 100, ‘MaxGenerations’, 200, ‘UseParallel’, true,’NonlinearConstraintAlgorithm’,’penalty’,’PlotFcn’,’gaplotbestindiv’,’InitialPopulationMatrix’,p_initial);
nvars=4;
[p_opt, fval, exitflag, output] = ga(@(p)(error_function(p, strain, stress)), nvars, [], [], [], [], lb, ub, [], options);

%check plot e ricostruzione del modello con i parametri ottimizzati
c = p_opt(1); % c
k1 = p_opt(2); % k1
k2 = p_opt(3); % k2
zeta = p_opt(4); % zeta
for i=1:length(strain)

sigma_calculated(i)=c*(strain(i)^2) + 2*strain(i)^2*k1*((strain(i)^2-1)*(i-zeta)^2*exp(k2*(strain(i)^2-1)^2*(1-zeta)^2));

end

% for i=1:length(strain)
% f = [strain(i) 0 0; %deformation gradient for each value of strain
% 0 1/sqrt(strain(i)) 0;
% 0 0 1/sqrt(strain(i))];
% C = f .* f’; % Calcola il tensore di Cauchy-Green
% prodot = a0 .* a0′;
% I4 = sum(sum(C .* prodot)); % calcolo invariante di C
% I = eye(3); % Matrice identità
%
% sigma= f*c*I*f’ + 2*f*(k1 * (1 – zeta)^2 * (I4 – 1) * (exp(k2 * ((1 – zeta) * (I4 – 1))^2)) * prodot)*f’;
%
% sigma_calculated(i)= sigma(1,1); %componente xx
% end

figure()
plot (strain,stress);
hold on
plot(strain, sigma_calculated,’r’);
legend (‘experimental’, ‘model’,’Location’, ‘northwest’);

function error = error_function(p,strain,stress)

sigma_calculated = zeros(length(strain), 1);

for i = 2:length(strain) %avoiding first value=0;

% f = [strain(i) 0 0; %deformation gradient
% 0 1/sqrt(strain(i)) 0;
% 0 0 1/sqrt(strain(i))];
% C = f .* f’; % tensore di Cauchy-Green
% prodot = a0 .* a0′;
% I4 = a0′ .* C .* a0; % calcolo IV invariante di C
% I = eye(3);
%
% sigma= f*p(1)*I*f’ + 2*f*(p(2) * (1 – p(4))^2 * (I4 – 1) * (exp(p(3) * ((1 – p(4)) * (I4 – 1))^2)) * prodot)*f’;
%
%
% sigma_calculated(i)= sigma(1,1); %componente xx
sigma_calculated(i)=p(1)*(strain(i)^2) + 2*strain(i)^2*p(2)*((strain(i)^2-1)*(i-p(4))^2*exp(p(3)*(strain(i)^2-1)^2*(1-p(4))^2));

end

error= sum((sigma_calculated-stress).^2) ; %/sum(stress).^2; % Somma dei quadrati delle differenze
%aggiungere normalizzazione rispetto allo stress( guardare script marta calcolo error )
end I have a constitutive model with 4 parameters to fit to experimental stress vs strain data. Before implementing the GA, I tried lsqnonlin (with and without multistart), but one of the main problems is that the algorithm often tends to assign bound values to the optimised parameters. To the first parameter, which is larger than the others, it assigns the upper bound, to the second and third it assigns the lower bounds. Plotting the best individuals over time, it appears that the ga spans little between the solutions, and the optimisation seems to be biased towards the first parameter.
I am using the uniaxial model proposed by Dong, and have rechecked the correctness of the model form several times. Below is the main containing the ga and my error function. Any help is welcome, thank you

%CHANGE LINE 3 TO SELECT THE PATCH
%CHANGE LINES 9 AND 10 TO SELECT THE SPECIMEN
clc; clear all;close all;
load ("data_11122.mat"); % change lot number if necessary
clearvars -except data

%Model requires lambda= x/x0 instead of epsilon: calculate lambda
% from exp data and store in data struct

stress=data(6).stress; %change index to change dogbone if necessary
stress=stress/max(stress);
strain=data(6).strain; %change index to change dogbone if necessary
p_initial=[50 25 5 .5]*10e-3;
a0=[1 0 0];
%vincoli su zeta imposti da dong ( zeta tra 0 e 1 )
lb=[0 0 0 0]; %% AGGIUSTA UNITA DIN MISURA
ub=[650 98 35 1];

%ottimizzazione non lineare con metodo least square ( like Dong )
options = optimoptions(‘ga’, ‘Display’, ‘iter’, ‘PopulationSize’, 100, ‘MaxGenerations’, 200, ‘UseParallel’, true,’NonlinearConstraintAlgorithm’,’penalty’,’PlotFcn’,’gaplotbestindiv’,’InitialPopulationMatrix’,p_initial);
nvars=4;
[p_opt, fval, exitflag, output] = ga(@(p)(error_function(p, strain, stress)), nvars, [], [], [], [], lb, ub, [], options);

%check plot e ricostruzione del modello con i parametri ottimizzati
c = p_opt(1); % c
k1 = p_opt(2); % k1
k2 = p_opt(3); % k2
zeta = p_opt(4); % zeta
for i=1:length(strain)

sigma_calculated(i)=c*(strain(i)^2) + 2*strain(i)^2*k1*((strain(i)^2-1)*(i-zeta)^2*exp(k2*(strain(i)^2-1)^2*(1-zeta)^2));

end

% for i=1:length(strain)
% f = [strain(i) 0 0; %deformation gradient for each value of strain
% 0 1/sqrt(strain(i)) 0;
% 0 0 1/sqrt(strain(i))];
% C = f .* f’; % Calcola il tensore di Cauchy-Green
% prodot = a0 .* a0′;
% I4 = sum(sum(C .* prodot)); % calcolo invariante di C
% I = eye(3); % Matrice identità
%
% sigma= f*c*I*f’ + 2*f*(k1 * (1 – zeta)^2 * (I4 – 1) * (exp(k2 * ((1 – zeta) * (I4 – 1))^2)) * prodot)*f’;
%
% sigma_calculated(i)= sigma(1,1); %componente xx
% end

figure()
plot (strain,stress);
hold on
plot(strain, sigma_calculated,’r’);
legend (‘experimental’, ‘model’,’Location’, ‘northwest’);

function error = error_function(p,strain,stress)

sigma_calculated = zeros(length(strain), 1);

for i = 2:length(strain) %avoiding first value=0;

% f = [strain(i) 0 0; %deformation gradient
% 0 1/sqrt(strain(i)) 0;
% 0 0 1/sqrt(strain(i))];
% C = f .* f’; % tensore di Cauchy-Green
% prodot = a0 .* a0′;
% I4 = a0′ .* C .* a0; % calcolo IV invariante di C
% I = eye(3);
%
% sigma= f*p(1)*I*f’ + 2*f*(p(2) * (1 – p(4))^2 * (I4 – 1) * (exp(p(3) * ((1 – p(4)) * (I4 – 1))^2)) * prodot)*f’;
%
%
% sigma_calculated(i)= sigma(1,1); %componente xx
sigma_calculated(i)=p(1)*(strain(i)^2) + 2*strain(i)^2*p(2)*((strain(i)^2-1)*(i-p(4))^2*exp(p(3)*(strain(i)^2-1)^2*(1-p(4))^2));

end

error= sum((sigma_calculated-stress).^2) ; %/sum(stress).^2; % Somma dei quadrati delle differenze
%aggiungere normalizzazione rispetto allo stress( guardare script marta calcolo error )
end ga, optimization, nonlinear, curve fitting MATLAB Answers — New Questions

​

Dear community,
I fing the geoglobe and geoplot3 functions reallly nice and powerful, yet I have been trying to plot a simple case without succeeding.
I want to plot lines that are located below the surface (underground tunnels, wells, etc.). Is there a workaround to play with the ground layer "transparency" to see those lines that are drawn efectively below, but hidden by the surface?
An extract of the code I’m using:
uif = uifigure;
lat=[43.93365285 43.94086810];
lon=[5.48483510 5.48376465];
alt=[483.591 499.640];
g = geoglobe(uif,’Basemap’,’satellite’,"Terrain","gmted2010");
geoplot3(g,lat,lon,alt,’r’,"LineWidth",2)
campos(g,43.912,5.465,700);
campitch(g,0)
camheading(g,20)
Thanks a lot in advance.Dear community,
I fing the geoglobe and geoplot3 functions reallly nice and powerful, yet I have been trying to plot a simple case without succeeding.
I want to plot lines that are located below the surface (underground tunnels, wells, etc.). Is there a workaround to play with the ground layer "transparency" to see those lines that are drawn efectively below, but hidden by the surface?
An extract of the code I’m using:
uif = uifigure;
lat=[43.93365285 43.94086810];
lon=[5.48483510 5.48376465];
alt=[483.591 499.640];
g = geoglobe(uif,’Basemap’,’satellite’,"Terrain","gmted2010");
geoplot3(g,lat,lon,alt,’r’,"LineWidth",2)
campos(g,43.912,5.465,700);
campitch(g,0)
camheading(g,20)
Thanks a lot in advance. Dear community,
I fing the geoglobe and geoplot3 functions reallly nice and powerful, yet I have been trying to plot a simple case without succeeding.
I want to plot lines that are located below the surface (underground tunnels, wells, etc.). Is there a workaround to play with the ground layer "transparency" to see those lines that are drawn efectively below, but hidden by the surface?
An extract of the code I’m using:
uif = uifigure;
lat=[43.93365285 43.94086810];
lon=[5.48483510 5.48376465];
alt=[483.591 499.640];
g = geoglobe(uif,’Basemap’,’satellite’,"Terrain","gmted2010");
geoplot3(g,lat,lon,alt,’r’,"LineWidth",2)
campos(g,43.912,5.465,700);
campitch(g,0)
camheading(g,20)
Thanks a lot in advance. geoplot3 MATLAB Answers — New Questions

​