I’m developing a Field Oriented Control (FOC) system for an Induction Motor (IM) in Simulink. The model includes:
Inverter driven by a PWM block
Rotor position and speed measurement or estimation
Clarke and Park transformations
PID controllers for Id and Iq
Reference inputs for rotor flux and rotor angle (θ_r)
The PID controllers are configured with standard parameters and anti-windup enabled
Issue:
The electromagnetic torque Te stays at zero, even when a non-zero speed reference is applied
Only one of the PWM output voltages reaches Vdc; the other two remain very low or close to zero
Checks already performed:
The motor feedback currents seem correct
Iq ≠ 0 and Id = 0, as expected
The inverter output voltages toward the motor appear to be valid
The reference signals reach the PID controllers properly
Attached:
A picture of the full FOC model in Simulink
Parameter settings of the induction motor
Scopes showing Te and the PWM input signalsI’m developing a Field Oriented Control (FOC) system for an Induction Motor (IM) in Simulink. The model includes:
Inverter driven by a PWM block
Rotor position and speed measurement or estimation
Clarke and Park transformations
PID controllers for Id and Iq
Reference inputs for rotor flux and rotor angle (θ_r)
The PID controllers are configured with standard parameters and anti-windup enabled
Issue:
The electromagnetic torque Te stays at zero, even when a non-zero speed reference is applied
Only one of the PWM output voltages reaches Vdc; the other two remain very low or close to zero
Checks already performed:
The motor feedback currents seem correct
Iq ≠ 0 and Id = 0, as expected
The inverter output voltages toward the motor appear to be valid
The reference signals reach the PID controllers properly
Attached:
A picture of the full FOC model in Simulink
Parameter settings of the induction motor
Scopes showing Te and the PWM input signals I’m developing a Field Oriented Control (FOC) system for an Induction Motor (IM) in Simulink. The model includes:
Inverter driven by a PWM block
Rotor position and speed measurement or estimation
Clarke and Park transformations
PID controllers for Id and Iq
Reference inputs for rotor flux and rotor angle (θ_r)
The PID controllers are configured with standard parameters and anti-windup enabled
Issue:
The electromagnetic torque Te stays at zero, even when a non-zero speed reference is applied
Only one of the PWM output voltages reaches Vdc; the other two remain very low or close to zero
Checks already performed:
The motor feedback currents seem correct
Iq ≠ 0 and Id = 0, as expected
The inverter output voltages toward the motor appear to be valid
The reference signals reach the PID controllers properly
Attached:
A picture of the full FOC model in Simulink
Parameter settings of the induction motor
Scopes showing Te and the PWM input signals foc, simulink, matlab, induction-motor, pwm, vector control, te zero MATLAB Answers — New Questions

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I am using MATLAB’s Classification Learner App to train multiple models (e.g., SVM, KNN, NN, etc.) on my dataset. The app displays the confusion matrix for each model individually, which is helpful.
For my research, I want to export the predicted class labels along with the true class labels for each trained model into a single .csv or .xlsx file — ideally including:
Model name
True class label
Predicted class label
How can I export these predictions for all models from Classification Learner into a table form from the classifier learner?I am using MATLAB’s Classification Learner App to train multiple models (e.g., SVM, KNN, NN, etc.) on my dataset. The app displays the confusion matrix for each model individually, which is helpful.
For my research, I want to export the predicted class labels along with the true class labels for each trained model into a single .csv or .xlsx file — ideally including:
Model name
True class label
Predicted class label
How can I export these predictions for all models from Classification Learner into a table form from the classifier learner? I am using MATLAB’s Classification Learner App to train multiple models (e.g., SVM, KNN, NN, etc.) on my dataset. The app displays the confusion matrix for each model individually, which is helpful.
For my research, I want to export the predicted class labels along with the true class labels for each trained model into a single .csv or .xlsx file — ideally including:
Model name
True class label
Predicted class label
How can I export these predictions for all models from Classification Learner into a table form from the classifier learner? confusion matrix, csv file MATLAB Answers — New Questions

​

I am solving dispersion equation for water waves. I already solved it but with small h now i am using the same code but having different h and it give me incorrect evenscent modes. How i can fix my this code that it works well. Below is my code
clc;
close all;
clear all;

N = 10; % Terms number used in region I

% — 2. Dimensional geometry & environment ———————
RI = 34.5; % [m] inner / entrance radius (fully open ⇒ RI = RT)
RE = 47.5; % [m] outer hull radius (used for k0*RE axis)
d = 38.0; % [m] draft = free-surface → rim (water-column length)
h = 200; % [m] total water depth (free-surface → seabed)
b = h – d; % [m] clearance rim → seabed (= 162 m, not usually used)
g=9.81;

k0RE = linspace(5, 35, 200); % 200 points, dimension-less

I_given_wavenumber = 1;
% ————— ① pre-allocate
for j = 1:length(k0RE)
if I_given_wavenumber == 1
wk = k0RE(j)/RE; %wavenumber
omega = sqrt(g*wk*tanh(wk*h)); %wave radian frequency

fun_alpha = @(x) omega^2 + g*x*tan(x*h); %dispersion equation for evanescent modes

end
for n = 1:N
if n ==1
k(n) = -1i*wk;

else
x0_alpha = [(2*n -3)*pi/2./h, (2*n -1)*pi/2./h]; % Narrow interval
k(n) = fsolve(fun_alpha, mean(x0_alpha));
end
end

endI am solving dispersion equation for water waves. I already solved it but with small h now i am using the same code but having different h and it give me incorrect evenscent modes. How i can fix my this code that it works well. Below is my code
clc;
close all;
clear all;

N = 10; % Terms number used in region I

% — 2. Dimensional geometry & environment ———————
RI = 34.5; % [m] inner / entrance radius (fully open ⇒ RI = RT)
RE = 47.5; % [m] outer hull radius (used for k0*RE axis)
d = 38.0; % [m] draft = free-surface → rim (water-column length)
h = 200; % [m] total water depth (free-surface → seabed)
b = h – d; % [m] clearance rim → seabed (= 162 m, not usually used)
g=9.81;

k0RE = linspace(5, 35, 200); % 200 points, dimension-less

I_given_wavenumber = 1;
% ————— ① pre-allocate
for j = 1:length(k0RE)
if I_given_wavenumber == 1
wk = k0RE(j)/RE; %wavenumber
omega = sqrt(g*wk*tanh(wk*h)); %wave radian frequency

fun_alpha = @(x) omega^2 + g*x*tan(x*h); %dispersion equation for evanescent modes

end
for n = 1:N
if n ==1
k(n) = -1i*wk;

else
x0_alpha = [(2*n -3)*pi/2./h, (2*n -1)*pi/2./h]; % Narrow interval
k(n) = fsolve(fun_alpha, mean(x0_alpha));
end
end

end I am solving dispersion equation for water waves. I already solved it but with small h now i am using the same code but having different h and it give me incorrect evenscent modes. How i can fix my this code that it works well. Below is my code
clc;
close all;
clear all;

N = 10; % Terms number used in region I

% — 2. Dimensional geometry & environment ———————
RI = 34.5; % [m] inner / entrance radius (fully open ⇒ RI = RT)
RE = 47.5; % [m] outer hull radius (used for k0*RE axis)
d = 38.0; % [m] draft = free-surface → rim (water-column length)
h = 200; % [m] total water depth (free-surface → seabed)
b = h – d; % [m] clearance rim → seabed (= 162 m, not usually used)
g=9.81;

k0RE = linspace(5, 35, 200); % 200 points, dimension-less

I_given_wavenumber = 1;
% ————— ① pre-allocate
for j = 1:length(k0RE)
if I_given_wavenumber == 1
wk = k0RE(j)/RE; %wavenumber
omega = sqrt(g*wk*tanh(wk*h)); %wave radian frequency

fun_alpha = @(x) omega^2 + g*x*tan(x*h); %dispersion equation for evanescent modes

end
for n = 1:N
if n ==1
k(n) = -1i*wk;

else
x0_alpha = [(2*n -3)*pi/2./h, (2*n -1)*pi/2./h]; % Narrow interval
k(n) = fsolve(fun_alpha, mean(x0_alpha));
end
end

end evenscent modes, dispersion equation, water waves MATLAB Answers — New Questions

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I’m working on Stateflow Onramp > Creating State Charts > Default Transitions and Unreachable States (Task 4). The task asks to:
Add a transition from Off to On.
I added the transition exactly as shown in the solution — from the edge of the Off state to the edge of the On state. The chart visually matches the solution, and there’s a default transition to Off.
However, after clicking Submit, I still get the message:
Sorry, that answer is incorrect. Please review the requirements on the right side.
There are no conditions or events on the transition (as per the example), and both states are reachable, as both get highlighted during the run.
What could I be missing? Is there a hidden requirement not shown in the visual solution?
Thanks in advance!I’m working on Stateflow Onramp > Creating State Charts > Default Transitions and Unreachable States (Task 4). The task asks to:
Add a transition from Off to On.
I added the transition exactly as shown in the solution — from the edge of the Off state to the edge of the On state. The chart visually matches the solution, and there’s a default transition to Off.
However, after clicking Submit, I still get the message:
Sorry, that answer is incorrect. Please review the requirements on the right side.
There are no conditions or events on the transition (as per the example), and both states are reachable, as both get highlighted during the run.
What could I be missing? Is there a hidden requirement not shown in the visual solution?
Thanks in advance! I’m working on Stateflow Onramp > Creating State Charts > Default Transitions and Unreachable States (Task 4). The task asks to:
Add a transition from Off to On.
I added the transition exactly as shown in the solution — from the edge of the Off state to the edge of the On state. The chart visually matches the solution, and there’s a default transition to Off.
However, after clicking Submit, I still get the message:
Sorry, that answer is incorrect. Please review the requirements on the right side.
There are no conditions or events on the transition (as per the example), and both states are reachable, as both get highlighted during the run.
What could I be missing? Is there a hidden requirement not shown in the visual solution?
Thanks in advance! stateflow onramp, stateflow, matlab, simulink MATLAB Answers — New Questions

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I have an m-file that reads an XML file to get inputs. I’m running into a problem with comments in the XML file. Simply put, if I put a comment inside the tag but before the value, then I get an empty string for the value. Comments elsewhere don’t cause problems
Here’s a toy example of my m-file:
function userInputStruct = readToyXmlInput()

toyXmlInputFile = ‘toyXmlInput.xml’;

xDoc = xmlread(toyXmlInputFile);

userInput = xDoc.getElementsByTagName(‘userInput’);

userInputStruct = struct(); % Initialize

thisUserInput = userInput.item(0);

thisInput_01 = thisUserInput.getElementsByTagName(‘input_01’);
thisInput_01Element = thisInput_01.item(0);
temp01 = thisInput_01Element.getFirstChild.getData;
temp02 = string(temp01);
input_01 = strip(temp02);

userInputStruct.input_01 = input_01;
Here’s a toy example of my XML file:
<toyXmlInput>
<userInput>
<!– A comment here is fine. –>
<input_01>
Dummy input #1 <!– A comment here is fine. –>
<!– A comment here is fine. –>
</input_01>
</userInput>
</toyXmlInput>
Here’s a toy example of my XML file with a comment that causes a problem.
<toyXmlInput>
<userInput>
<input_01>
<!– A comment here causes problems –>
Dummy input #1
</input_01>
</userInput>
</toyXmlInput>
What am I doing wrong? What can I do differently so that comments after the tag but before the value don’t cause problems?
Worst-case, I’ll just document in the m-file and the XML file that there’s a limit on where comments can go. However, I’d prefer a more elegant solution.I have an m-file that reads an XML file to get inputs. I’m running into a problem with comments in the XML file. Simply put, if I put a comment inside the tag but before the value, then I get an empty string for the value. Comments elsewhere don’t cause problems
Here’s a toy example of my m-file:
function userInputStruct = readToyXmlInput()

toyXmlInputFile = ‘toyXmlInput.xml’;

xDoc = xmlread(toyXmlInputFile);

userInput = xDoc.getElementsByTagName(‘userInput’);

userInputStruct = struct(); % Initialize

thisUserInput = userInput.item(0);

thisInput_01 = thisUserInput.getElementsByTagName(‘input_01’);
thisInput_01Element = thisInput_01.item(0);
temp01 = thisInput_01Element.getFirstChild.getData;
temp02 = string(temp01);
input_01 = strip(temp02);

userInputStruct.input_01 = input_01;
Here’s a toy example of my XML file:
<toyXmlInput>
<userInput>
<!– A comment here is fine. –>
<input_01>
Dummy input #1 <!– A comment here is fine. –>
<!– A comment here is fine. –>
</input_01>
</userInput>
</toyXmlInput>
Here’s a toy example of my XML file with a comment that causes a problem.
<toyXmlInput>
<userInput>
<input_01>
<!– A comment here causes problems –>
Dummy input #1
</input_01>
</userInput>
</toyXmlInput>
What am I doing wrong? What can I do differently so that comments after the tag but before the value don’t cause problems?
Worst-case, I’ll just document in the m-file and the XML file that there’s a limit on where comments can go. However, I’d prefer a more elegant solution. I have an m-file that reads an XML file to get inputs. I’m running into a problem with comments in the XML file. Simply put, if I put a comment inside the tag but before the value, then I get an empty string for the value. Comments elsewhere don’t cause problems
Here’s a toy example of my m-file:
function userInputStruct = readToyXmlInput()

toyXmlInputFile = ‘toyXmlInput.xml’;

xDoc = xmlread(toyXmlInputFile);

userInput = xDoc.getElementsByTagName(‘userInput’);

userInputStruct = struct(); % Initialize

thisUserInput = userInput.item(0);

thisInput_01 = thisUserInput.getElementsByTagName(‘input_01’);
thisInput_01Element = thisInput_01.item(0);
temp01 = thisInput_01Element.getFirstChild.getData;
temp02 = string(temp01);
input_01 = strip(temp02);

userInputStruct.input_01 = input_01;
Here’s a toy example of my XML file:
<toyXmlInput>
<userInput>
<!– A comment here is fine. –>
<input_01>
Dummy input #1 <!– A comment here is fine. –>
<!– A comment here is fine. –>
</input_01>
</userInput>
</toyXmlInput>
Here’s a toy example of my XML file with a comment that causes a problem.
<toyXmlInput>
<userInput>
<input_01>
<!– A comment here causes problems –>
Dummy input #1
</input_01>
</userInput>
</toyXmlInput>
What am I doing wrong? What can I do differently so that comments after the tag but before the value don’t cause problems?
Worst-case, I’ll just document in the m-file and the XML file that there’s a limit on where comments can go. However, I’d prefer a more elegant solution. xml, comment MATLAB Answers — New Questions

​

Hello everyone!
Settings
I am facing a very strange issue. Here is my situation : I am creating a Simulink model that call a complex Matlab function. The function, name MD, is take a nested struct as an input, named config. The struct will be updated meaning adding fields (only on the first call), and updated value.
After some research, I have understood that the best way to solve my problem is to create a type ‘bus :configbus’, via
Simulink.Bus.createObject(config)
evalin(‘base’, ‘configbus = slBus1;’);
clear("slBus1")

Then, in Simulink I have my Matlab function block, linked to Data Store Read / write for interfacing the config input. This is for the setup.
Adding fields
To solve the fact that on the first call I am adding fields, I run once the function MD, before the simulation and creating the bus, to get all the correct field. I am open to better solution that this bit if you have any.

Errors encounter
However, when configuring the Data Store Memory with the Initial value I get the following error (error1):
Invalid setting in ‘path to Data Store Read’ for parameter ‘InitialValue’.
I am trying the following combination:
Inital Value : config
type : Bus:configBus.
(my function as the input define as the correct type and there is no issue there)

When I run my model I get the error (error2):
Error using Leia_main (line 47)
Expression ‘configBus’ for type of data ‘config’ did not evaluate to a valid type.
Caused by:
Error using Leia_main (line 47)
Invalid setting in ‘Guidance/If Action Subsystem2/If Action Subsystem1/New Planing/MATLAB Function’ for parameter ‘Datatype’
Error using Leia_main (line 47)
Error evaluating MATLAB Function parameter data
‘Datatype’ in its parent workspace.
Error using Leia_main (line 47)
Unrecognized function or variable ‘configBus’.
Error using Leia_main (line 47)
Variable ‘configBus’ does not exist.
Suggested Actions:
• Load a file into base workspace. – Fix
• Create a new variable. – Fix

Which is really wierd, since it seems that Matlab is confusing the type and the variable. But I have checked and everything seems to be declare as it should.

My investigation
When I look at my top bus definition it do not seems that field corresponding to subbuses are mapped properly. Even though the correct bus type exist.
Here is an example :

SK_requirement is supposed to be of type bus: SK_requirement but is of type SK_requirement which I don’t know what type it points to.
And if I set it correctly I get :

Is there any reason why this is behaving like this ? I would expect that the configbus declartion to be correctly typed. (I will try to manually set the good type and see if there is any improvement). My naive guess is that it might solve error1, but not sure.

Questions
1) Is there a better way to create the top level bus ? Or is it just a bug ?
2) Do you have any idea for error1 ?
3) Do you have any idea for solutioning error2 ?
Information
Runing matlab25a without the last update. Using MacOS with Apple chip.

Thank you in advance for your insights.Hello everyone!
Settings
I am facing a very strange issue. Here is my situation : I am creating a Simulink model that call a complex Matlab function. The function, name MD, is take a nested struct as an input, named config. The struct will be updated meaning adding fields (only on the first call), and updated value.
After some research, I have understood that the best way to solve my problem is to create a type ‘bus :configbus’, via
Simulink.Bus.createObject(config)
evalin(‘base’, ‘configbus = slBus1;’);
clear("slBus1")

Then, in Simulink I have my Matlab function block, linked to Data Store Read / write for interfacing the config input. This is for the setup.
Adding fields
To solve the fact that on the first call I am adding fields, I run once the function MD, before the simulation and creating the bus, to get all the correct field. I am open to better solution that this bit if you have any.

Errors encounter
However, when configuring the Data Store Memory with the Initial value I get the following error (error1):
Invalid setting in ‘path to Data Store Read’ for parameter ‘InitialValue’.
I am trying the following combination:
Inital Value : config
type : Bus:configBus.
(my function as the input define as the correct type and there is no issue there)

When I run my model I get the error (error2):
Error using Leia_main (line 47)
Expression ‘configBus’ for type of data ‘config’ did not evaluate to a valid type.
Caused by:
Error using Leia_main (line 47)
Invalid setting in ‘Guidance/If Action Subsystem2/If Action Subsystem1/New Planing/MATLAB Function’ for parameter ‘Datatype’
Error using Leia_main (line 47)
Error evaluating MATLAB Function parameter data
‘Datatype’ in its parent workspace.
Error using Leia_main (line 47)
Unrecognized function or variable ‘configBus’.
Error using Leia_main (line 47)
Variable ‘configBus’ does not exist.
Suggested Actions:
• Load a file into base workspace. – Fix
• Create a new variable. – Fix

Which is really wierd, since it seems that Matlab is confusing the type and the variable. But I have checked and everything seems to be declare as it should.

My investigation
When I look at my top bus definition it do not seems that field corresponding to subbuses are mapped properly. Even though the correct bus type exist.
Here is an example :

SK_requirement is supposed to be of type bus: SK_requirement but is of type SK_requirement which I don’t know what type it points to.
And if I set it correctly I get :

Is there any reason why this is behaving like this ? I would expect that the configbus declartion to be correctly typed. (I will try to manually set the good type and see if there is any improvement). My naive guess is that it might solve error1, but not sure.

Questions
1) Is there a better way to create the top level bus ? Or is it just a bug ?
2) Do you have any idea for error1 ?
3) Do you have any idea for solutioning error2 ?
Information
Runing matlab25a without the last update. Using MacOS with Apple chip.

Thank you in advance for your insights. Hello everyone!
Settings
I am facing a very strange issue. Here is my situation : I am creating a Simulink model that call a complex Matlab function. The function, name MD, is take a nested struct as an input, named config. The struct will be updated meaning adding fields (only on the first call), and updated value.
After some research, I have understood that the best way to solve my problem is to create a type ‘bus :configbus’, via
Simulink.Bus.createObject(config)
evalin(‘base’, ‘configbus = slBus1;’);
clear("slBus1")

Then, in Simulink I have my Matlab function block, linked to Data Store Read / write for interfacing the config input. This is for the setup.
Adding fields
To solve the fact that on the first call I am adding fields, I run once the function MD, before the simulation and creating the bus, to get all the correct field. I am open to better solution that this bit if you have any.

Errors encounter
However, when configuring the Data Store Memory with the Initial value I get the following error (error1):
Invalid setting in ‘path to Data Store Read’ for parameter ‘InitialValue’.
I am trying the following combination:
Inital Value : config
type : Bus:configBus.
(my function as the input define as the correct type and there is no issue there)

When I run my model I get the error (error2):
Error using Leia_main (line 47)
Expression ‘configBus’ for type of data ‘config’ did not evaluate to a valid type.
Caused by:
Error using Leia_main (line 47)
Invalid setting in ‘Guidance/If Action Subsystem2/If Action Subsystem1/New Planing/MATLAB Function’ for parameter ‘Datatype’
Error using Leia_main (line 47)
Error evaluating MATLAB Function parameter data
‘Datatype’ in its parent workspace.
Error using Leia_main (line 47)
Unrecognized function or variable ‘configBus’.
Error using Leia_main (line 47)
Variable ‘configBus’ does not exist.
Suggested Actions:
• Load a file into base workspace. – Fix
• Create a new variable. – Fix

Which is really wierd, since it seems that Matlab is confusing the type and the variable. But I have checked and everything seems to be declare as it should.

My investigation
When I look at my top bus definition it do not seems that field corresponding to subbuses are mapped properly. Even though the correct bus type exist.
Here is an example :

SK_requirement is supposed to be of type bus: SK_requirement but is of type SK_requirement which I don’t know what type it points to.
And if I set it correctly I get :

Is there any reason why this is behaving like this ? I would expect that the configbus declartion to be correctly typed. (I will try to manually set the good type and see if there is any improvement). My naive guess is that it might solve error1, but not sure.

Questions
1) Is there a better way to create the top level bus ? Or is it just a bug ?
2) Do you have any idea for error1 ?
3) Do you have any idea for solutioning error2 ?
Information
Runing matlab25a without the last update. Using MacOS with Apple chip.

Thank you in advance for your insights. simulink, bus, sub-bus, type, datastorememory, matlab function MATLAB Answers — New Questions

​

Hello all,
I’m working on a MATLAB script that computes the merging contour between two turbulent plumes, using a custom root-finding function called mnhf_secant. This function implements a supervisor-provided secant method to solve a nonlinear equation that describes the interface between the plumes. The governing equation being solved is located at the bottom of the code and is derived from plume interaction theory.
The issue arises in the else branch of the loop that iterates over polar angles (θ). When the code enters this branch, the contour plot generated shows visible gaps between the red line (plume boundary) and the black line (reference contour), indicating that the solution is not continuous or fails to resolve in those regions.
This breakdown does not occur in the first half of the angular domain (handled by the if condition), where the contours are computed correctly as seen by the continuous black line. The discontinuity seems localized to the else loop, despite using the same root-finding logic.I tried different guesses for the secant function but is not helping to solve for the gaps.
My main question is:
Is there a modification I could implement in the else branch to ensure a continuous contour across the full angular domain? I have attached the code below.
close all; clc; clf
global r0 k theta
%% Parameter input, plume source of finite size
r0 = 1/3;
k_array = [0.3 0.5 0.7 1-r0^2 1]
Nt = 20001; % Must be odd for symmetry
theta_array = linspace(-pi/2, pi/2, Nt);
figure(1); hold on; box on
for jj = 1:length(k_array)
k = k_array(jj);
if k >= 1 – r0^2
rho_array1 = zeros(1,length(theta_array));
for ii = 1:length(theta_array)
theta = theta_array(ii);
rho_array1(ii) = mnhf_secant(@TwoPlumes_Equation, [1.5 2], 1e-6, 0);
if rho_array1(ii)<0
rho_array1(ii) = NaN;
end
end
[x1, y1] = pol2cart(theta_array, rho_array1);
plot(x1, y1, ‘-k’); axis square; xlim([0 2]); ylim([-1 1]);
else
rho_array1 = zeros(1,length(theta_array));
for ii = 1:length(theta_array)
theta = theta_array(ii);
rho_array1(ii) = mnhf_secant(@TwoPlumes_Equation, [1.5 2], 1e-6, 0);
if rho_array1(ii)<0
rho_array1(ii) = NaN;
end
end
[x1, y1] = pol2cart(theta_array, rho_array1);
plot(x1, y1, ‘-k’); axis square; xlim([0 2]); ylim([-1 1]);

% Identify breakdown angle where rho fails
ij = find(isnan(rho_array1(1:round(end/2))));
if ~isempty(ij)
theta_min = theta_array(max(ij)) % closest valid angle before breakdown
theta_array2 = linspace(theta_min, -theta_min, Nt); % symmetric gap domain
rho_array2 = zeros(1, length(theta_array2));

% Solve numerically in gap region
for ii = 1:length(theta_array2)
theta = theta_array2(ii);
rho_array2(ii) = mnhf_secant(@TwoPlumes_Equation, [0.1 0.4], 1e-6, 0);
if rho_array2(ii)<0
rho_array2(ii) = NaN;
end
end
[x2, y2] = pol2cart(theta_array2, rho_array2);
plot(x2, y2, ‘r.’); axis square; xlim([0 2]); ylim([-1 1]);
end
end
pos1 = [1 – r0, -r0, 2*r0, 2*r0];
rectangle(‘Position’, pos1, ‘Curvature’, [1 1], ‘FaceColor’, [0 0 0]);
end
function r=mnhf_secant(Fun,x,tol,trace)
%MNHF_SECANT finds the root of "Fun" using secant scheme.
%
% Fun – name of the external function
% x – vector of length 2, (initial guesses)
% tol – tolerance
% trace – print intermediate results
%
% Usage mnhf_secant(@poly1,[-0.5 2.0],1e-8,1)
% poly1 is the name of the external function.
% [-0.5 2.0] are the initial guesses for the root.
% Check inputs.
if nargin < 4, trace = 1; end
if nargin < 3, tol = 1e-8; end
if (length(x) ~= 2)
error(‘Please provide two initial guesses’)
end
f = feval(Fun,x); % Fun is assumed to accept a vector
for i = 1:100
x3 = x(1)-f(1)*(x(2)-x(1))/(f(2)-f(1)); % Update the guess.
f3 = feval(Fun,x3); % Function evaluation.
if trace, fprintf(1,’%3i %12.5f %12.5fn’, i,x3,f3); end
if abs(f3) < tol % Check for convergenece.
r = x3;
return
else % Reset values for x(1), x(2), f(1) and f(2).
x(1) = x(2); f(1) = f(2); x(2) = x3; f(2) = f3;
end
end
r = NaN;
end
%% Two-Plume Interaction Equation (B3 from LF20B)
function f = TwoPlumes_Equation(rho)
global r0 k theta
f = (rho.^2 – 2*rho.*cos(theta) + 1 – r0^2) .* …
(rho.^2 – 2*rho.*cos(theta + pi) + 1 – r0^2) – k^2;
endHello all,
I’m working on a MATLAB script that computes the merging contour between two turbulent plumes, using a custom root-finding function called mnhf_secant. This function implements a supervisor-provided secant method to solve a nonlinear equation that describes the interface between the plumes. The governing equation being solved is located at the bottom of the code and is derived from plume interaction theory.
The issue arises in the else branch of the loop that iterates over polar angles (θ). When the code enters this branch, the contour plot generated shows visible gaps between the red line (plume boundary) and the black line (reference contour), indicating that the solution is not continuous or fails to resolve in those regions.
This breakdown does not occur in the first half of the angular domain (handled by the if condition), where the contours are computed correctly as seen by the continuous black line. The discontinuity seems localized to the else loop, despite using the same root-finding logic.I tried different guesses for the secant function but is not helping to solve for the gaps.
My main question is:
Is there a modification I could implement in the else branch to ensure a continuous contour across the full angular domain? I have attached the code below.
close all; clc; clf
global r0 k theta
%% Parameter input, plume source of finite size
r0 = 1/3;
k_array = [0.3 0.5 0.7 1-r0^2 1]
Nt = 20001; % Must be odd for symmetry
theta_array = linspace(-pi/2, pi/2, Nt);
figure(1); hold on; box on
for jj = 1:length(k_array)
k = k_array(jj);
if k >= 1 – r0^2
rho_array1 = zeros(1,length(theta_array));
for ii = 1:length(theta_array)
theta = theta_array(ii);
rho_array1(ii) = mnhf_secant(@TwoPlumes_Equation, [1.5 2], 1e-6, 0);
if rho_array1(ii)<0
rho_array1(ii) = NaN;
end
end
[x1, y1] = pol2cart(theta_array, rho_array1);
plot(x1, y1, ‘-k’); axis square; xlim([0 2]); ylim([-1 1]);
else
rho_array1 = zeros(1,length(theta_array));
for ii = 1:length(theta_array)
theta = theta_array(ii);
rho_array1(ii) = mnhf_secant(@TwoPlumes_Equation, [1.5 2], 1e-6, 0);
if rho_array1(ii)<0
rho_array1(ii) = NaN;
end
end
[x1, y1] = pol2cart(theta_array, rho_array1);
plot(x1, y1, ‘-k’); axis square; xlim([0 2]); ylim([-1 1]);

% Identify breakdown angle where rho fails
ij = find(isnan(rho_array1(1:round(end/2))));
if ~isempty(ij)
theta_min = theta_array(max(ij)) % closest valid angle before breakdown
theta_array2 = linspace(theta_min, -theta_min, Nt); % symmetric gap domain
rho_array2 = zeros(1, length(theta_array2));

% Solve numerically in gap region
for ii = 1:length(theta_array2)
theta = theta_array2(ii);
rho_array2(ii) = mnhf_secant(@TwoPlumes_Equation, [0.1 0.4], 1e-6, 0);
if rho_array2(ii)<0
rho_array2(ii) = NaN;
end
end
[x2, y2] = pol2cart(theta_array2, rho_array2);
plot(x2, y2, ‘r.’); axis square; xlim([0 2]); ylim([-1 1]);
end
end
pos1 = [1 – r0, -r0, 2*r0, 2*r0];
rectangle(‘Position’, pos1, ‘Curvature’, [1 1], ‘FaceColor’, [0 0 0]);
end
function r=mnhf_secant(Fun,x,tol,trace)
%MNHF_SECANT finds the root of "Fun" using secant scheme.
%
% Fun – name of the external function
% x – vector of length 2, (initial guesses)
% tol – tolerance
% trace – print intermediate results
%
% Usage mnhf_secant(@poly1,[-0.5 2.0],1e-8,1)
% poly1 is the name of the external function.
% [-0.5 2.0] are the initial guesses for the root.
% Check inputs.
if nargin < 4, trace = 1; end
if nargin < 3, tol = 1e-8; end
if (length(x) ~= 2)
error(‘Please provide two initial guesses’)
end
f = feval(Fun,x); % Fun is assumed to accept a vector
for i = 1:100
x3 = x(1)-f(1)*(x(2)-x(1))/(f(2)-f(1)); % Update the guess.
f3 = feval(Fun,x3); % Function evaluation.
if trace, fprintf(1,’%3i %12.5f %12.5fn’, i,x3,f3); end
if abs(f3) < tol % Check for convergenece.
r = x3;
return
else % Reset values for x(1), x(2), f(1) and f(2).
x(1) = x(2); f(1) = f(2); x(2) = x3; f(2) = f3;
end
end
r = NaN;
end
%% Two-Plume Interaction Equation (B3 from LF20B)
function f = TwoPlumes_Equation(rho)
global r0 k theta
f = (rho.^2 – 2*rho.*cos(theta) + 1 – r0^2) .* …
(rho.^2 – 2*rho.*cos(theta + pi) + 1 – r0^2) – k^2;
end Hello all,
I’m working on a MATLAB script that computes the merging contour between two turbulent plumes, using a custom root-finding function called mnhf_secant. This function implements a supervisor-provided secant method to solve a nonlinear equation that describes the interface between the plumes. The governing equation being solved is located at the bottom of the code and is derived from plume interaction theory.
The issue arises in the else branch of the loop that iterates over polar angles (θ). When the code enters this branch, the contour plot generated shows visible gaps between the red line (plume boundary) and the black line (reference contour), indicating that the solution is not continuous or fails to resolve in those regions.
This breakdown does not occur in the first half of the angular domain (handled by the if condition), where the contours are computed correctly as seen by the continuous black line. The discontinuity seems localized to the else loop, despite using the same root-finding logic.I tried different guesses for the secant function but is not helping to solve for the gaps.
My main question is:
Is there a modification I could implement in the else branch to ensure a continuous contour across the full angular domain? I have attached the code below.
close all; clc; clf
global r0 k theta
%% Parameter input, plume source of finite size
r0 = 1/3;
k_array = [0.3 0.5 0.7 1-r0^2 1]
Nt = 20001; % Must be odd for symmetry
theta_array = linspace(-pi/2, pi/2, Nt);
figure(1); hold on; box on
for jj = 1:length(k_array)
k = k_array(jj);
if k >= 1 – r0^2
rho_array1 = zeros(1,length(theta_array));
for ii = 1:length(theta_array)
theta = theta_array(ii);
rho_array1(ii) = mnhf_secant(@TwoPlumes_Equation, [1.5 2], 1e-6, 0);
if rho_array1(ii)<0
rho_array1(ii) = NaN;
end
end
[x1, y1] = pol2cart(theta_array, rho_array1);
plot(x1, y1, ‘-k’); axis square; xlim([0 2]); ylim([-1 1]);
else
rho_array1 = zeros(1,length(theta_array));
for ii = 1:length(theta_array)
theta = theta_array(ii);
rho_array1(ii) = mnhf_secant(@TwoPlumes_Equation, [1.5 2], 1e-6, 0);
if rho_array1(ii)<0
rho_array1(ii) = NaN;
end
end
[x1, y1] = pol2cart(theta_array, rho_array1);
plot(x1, y1, ‘-k’); axis square; xlim([0 2]); ylim([-1 1]);

% Identify breakdown angle where rho fails
ij = find(isnan(rho_array1(1:round(end/2))));
if ~isempty(ij)
theta_min = theta_array(max(ij)) % closest valid angle before breakdown
theta_array2 = linspace(theta_min, -theta_min, Nt); % symmetric gap domain
rho_array2 = zeros(1, length(theta_array2));

% Solve numerically in gap region
for ii = 1:length(theta_array2)
theta = theta_array2(ii);
rho_array2(ii) = mnhf_secant(@TwoPlumes_Equation, [0.1 0.4], 1e-6, 0);
if rho_array2(ii)<0
rho_array2(ii) = NaN;
end
end
[x2, y2] = pol2cart(theta_array2, rho_array2);
plot(x2, y2, ‘r.’); axis square; xlim([0 2]); ylim([-1 1]);
end
end
pos1 = [1 – r0, -r0, 2*r0, 2*r0];
rectangle(‘Position’, pos1, ‘Curvature’, [1 1], ‘FaceColor’, [0 0 0]);
end
function r=mnhf_secant(Fun,x,tol,trace)
%MNHF_SECANT finds the root of "Fun" using secant scheme.
%
% Fun – name of the external function
% x – vector of length 2, (initial guesses)
% tol – tolerance
% trace – print intermediate results
%
% Usage mnhf_secant(@poly1,[-0.5 2.0],1e-8,1)
% poly1 is the name of the external function.
% [-0.5 2.0] are the initial guesses for the root.
% Check inputs.
if nargin < 4, trace = 1; end
if nargin < 3, tol = 1e-8; end
if (length(x) ~= 2)
error(‘Please provide two initial guesses’)
end
f = feval(Fun,x); % Fun is assumed to accept a vector
for i = 1:100
x3 = x(1)-f(1)*(x(2)-x(1))/(f(2)-f(1)); % Update the guess.
f3 = feval(Fun,x3); % Function evaluation.
if trace, fprintf(1,’%3i %12.5f %12.5fn’, i,x3,f3); end
if abs(f3) < tol % Check for convergenece.
r = x3;
return
else % Reset values for x(1), x(2), f(1) and f(2).
x(1) = x(2); f(1) = f(2); x(2) = x3; f(2) = f3;
end
end
r = NaN;
end
%% Two-Plume Interaction Equation (B3 from LF20B)
function f = TwoPlumes_Equation(rho)
global r0 k theta
f = (rho.^2 – 2*rho.*cos(theta) + 1 – r0^2) .* …
(rho.^2 – 2*rho.*cos(theta + pi) + 1 – r0^2) – k^2;
end numerical method, contour plot, discontinuities MATLAB Answers — New Questions

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While I can see what licenses I have active for my account, the installs are associated to computer labels. How can I determine what computer label a current PC has?
I ask as I am upgrading my PC and want to deactivate a given license, but I need to know which.
Thank you.While I can see what licenses I have active for my account, the installs are associated to computer labels. How can I determine what computer label a current PC has?
I ask as I am upgrading my PC and want to deactivate a given license, but I need to know which.
Thank you. While I can see what licenses I have active for my account, the installs are associated to computer labels. How can I determine what computer label a current PC has?
I ask as I am upgrading my PC and want to deactivate a given license, but I need to know which.
Thank you. licensing MATLAB Answers — New Questions

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Why do I see the wrong Service End Date in my License Center?Why do I see the wrong Service End Date in my License Center? Why do I see the wrong Service End Date in my License Center?  MATLAB Answers — New Questions

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