Hi,
I’m trying to write a code which can determine the gradient change in a given profile. However the code is unable to determine the same correctly and giving incorrect results. For the pic1 below it should give me the width of the region where it is a steep gradient determined.

However for pic2 below it shouldn’t as there is no steep gradient compared to pic1

The code is as below:
clear width;

global width;
global data;

for i=1:max(length(data.variable.t))
for j=1:max(length(data.variable.x))-1
change_p = (abs(data.variable.gradpressure(i,j+1))-abs(data.variable.gradpressure(i,j)))/abs(data.variable.gradpressure(i,j));
%disp(change_p)
if change_p > 0.1
disp("steep gradient found")
width(j)=1-data.variable.x(j);
disp(width)
else
disp("no steep gradient found")
end

end

end

the data.variable.gradpressure is a 1000×100 matrix with t along the vertical and x along the horizontal.
with regards,
rcHi,
I’m trying to write a code which can determine the gradient change in a given profile. However the code is unable to determine the same correctly and giving incorrect results. For the pic1 below it should give me the width of the region where it is a steep gradient determined.

However for pic2 below it shouldn’t as there is no steep gradient compared to pic1

The code is as below:
clear width;

global width;
global data;

for i=1:max(length(data.variable.t))
for j=1:max(length(data.variable.x))-1
change_p = (abs(data.variable.gradpressure(i,j+1))-abs(data.variable.gradpressure(i,j)))/abs(data.variable.gradpressure(i,j));
%disp(change_p)
if change_p > 0.1
disp("steep gradient found")
width(j)=1-data.variable.x(j);
disp(width)
else
disp("no steep gradient found")
end

end

end

the data.variable.gradpressure is a 1000×100 matrix with t along the vertical and x along the horizontal.
with regards,
rc Hi,
I’m trying to write a code which can determine the gradient change in a given profile. However the code is unable to determine the same correctly and giving incorrect results. For the pic1 below it should give me the width of the region where it is a steep gradient determined.

However for pic2 below it shouldn’t as there is no steep gradient compared to pic1

The code is as below:
clear width;

global width;
global data;

for i=1:max(length(data.variable.t))
for j=1:max(length(data.variable.x))-1
change_p = (abs(data.variable.gradpressure(i,j+1))-abs(data.variable.gradpressure(i,j)))/abs(data.variable.gradpressure(i,j));
%disp(change_p)
if change_p > 0.1
disp("steep gradient found")
width(j)=1-data.variable.x(j);
disp(width)
else
disp("no steep gradient found")
end

end

end

the data.variable.gradpressure is a 1000×100 matrix with t along the vertical and x along the horizontal.
with regards,
rc gradient MATLAB Answers — New Questions

​

I want to use a self-made DAQ board for simulink desktop real time, with connecting my computor and DAQ board through serial port. But everytime I run the simulation, error "The board ‘Standard Devices Serial Port’ has no Analog Input channels." occurs. How to solve this problem?I want to use a self-made DAQ board for simulink desktop real time, with connecting my computor and DAQ board through serial port. But everytime I run the simulation, error "The board ‘Standard Devices Serial Port’ has no Analog Input channels." occurs. How to solve this problem? I want to use a self-made DAQ board for simulink desktop real time, with connecting my computor and DAQ board through serial port. But everytime I run the simulation, error "The board ‘Standard Devices Serial Port’ has no Analog Input channels." occurs. How to solve this problem? simulink desktop real time MATLAB Answers — New Questions

​

I have a deep CNN network with 39 layers. While training the network is producing NaN output so the loss function is also producing NaN values. My network also has some custom layers which uses ‘dlconv’ where the weights are intialized using ‘initializeGlorot’ function. Why the network is producing ‘NaN’ outputs? Is there any way to solve this? Kindly request to provide suggestions.
Thanking,
BipinI have a deep CNN network with 39 layers. While training the network is producing NaN output so the loss function is also producing NaN values. My network also has some custom layers which uses ‘dlconv’ where the weights are intialized using ‘initializeGlorot’ function. Why the network is producing ‘NaN’ outputs? Is there any way to solve this? Kindly request to provide suggestions.
Thanking,
Bipin I have a deep CNN network with 39 layers. While training the network is producing NaN output so the loss function is also producing NaN values. My network also has some custom layers which uses ‘dlconv’ where the weights are intialized using ‘initializeGlorot’ function. Why the network is producing ‘NaN’ outputs? Is there any way to solve this? Kindly request to provide suggestions.
Thanking,
Bipin matlab, matlab gui, matlab code, deep learning, signal processing, digital signal processing, digital image processing, image processing, image, image analysis, image acquisition, image segmentation, signal, machine learning, matrix, matrices, matrix array, matrix manipulation, data, data preprocessing, deep learning toolbox, convolutional neural network, classification, class MATLAB Answers — New Questions

​

I am having the same problem as described in:
https://au.mathworks.com/matlabcentral/answers/102622-why-does-rref-give-significantly-different-answers-than-for-solutions-of-some-systems-in-matlab
The answer given is an attached MATLAB file, "rrefNoRational.m" which is a copy of "rref.m" without the code that performs the rational conversion that is the cause of the problem. However, I cannot find the attached file. Could the file rrefNoRational.m please be provided?
Thank you for your time.I am having the same problem as described in:
https://au.mathworks.com/matlabcentral/answers/102622-why-does-rref-give-significantly-different-answers-than-for-solutions-of-some-systems-in-matlab
The answer given is an attached MATLAB file, "rrefNoRational.m" which is a copy of "rref.m" without the code that performs the rational conversion that is the cause of the problem. However, I cannot find the attached file. Could the file rrefNoRational.m please be provided?
Thank you for your time. I am having the same problem as described in:
https://au.mathworks.com/matlabcentral/answers/102622-why-does-rref-give-significantly-different-answers-than-for-solutions-of-some-systems-in-matlab
The answer given is an attached MATLAB file, "rrefNoRational.m" which is a copy of "rref.m" without the code that performs the rational conversion that is the cause of the problem. However, I cannot find the attached file. Could the file rrefNoRational.m please be provided?
Thank you for your time. rref, rrefrrefnorational MATLAB Answers — New Questions

​

I get the following error message.
"Error using hdlcoder.pirctx/balancePathDelays
Unexpected error during HDL Code Generation.
Contact support@mathworks.com with reproduction steps.
Assertion failed with debug message:
B:matlabsrccgir_hdlpir_transformsPropagateInitVal.cpp:204:getInitVal(s) == InitVal::NOT_VISITED"
It seems like the error is not always there. After matlab and computer restarts combined with mutliple tries i eventiually get "lucky" and able to generate hdl. The model contains simulink nr ldpc decoder which I suspect is the problem.I get the following error message.
"Error using hdlcoder.pirctx/balancePathDelays
Unexpected error during HDL Code Generation.
Contact support@mathworks.com with reproduction steps.
Assertion failed with debug message:
B:matlabsrccgir_hdlpir_transformsPropagateInitVal.cpp:204:getInitVal(s) == InitVal::NOT_VISITED"
It seems like the error is not always there. After matlab and computer restarts combined with mutliple tries i eventiually get "lucky" and able to generate hdl. The model contains simulink nr ldpc decoder which I suspect is the problem. I get the following error message.
"Error using hdlcoder.pirctx/balancePathDelays
Unexpected error during HDL Code Generation.
Contact support@mathworks.com with reproduction steps.
Assertion failed with debug message:
B:matlabsrccgir_hdlpir_transformsPropagateInitVal.cpp:204:getInitVal(s) == InitVal::NOT_VISITED"
It seems like the error is not always there. After matlab and computer restarts combined with mutliple tries i eventiually get "lucky" and able to generate hdl. The model contains simulink nr ldpc decoder which I suspect is the problem. hdl coder, nr ldpc decodeer MATLAB Answers — New Questions

​

Hello everyone,
I am encountering an issue with calculating the average frequency in MATLAB. The average frequency result is unexpectedly high and varies with each execution, even though the audio input remains unchanged. Conversely, using the same audio in Python yields more consistent and reasonable results.
If anyone can identify the problem and help fix my MATLAB code, it would be greatly appreciated. Below are two versions of the code: the first records sound directly in MATLAB, and the second processes an existing audio file.
Thank you for your assistance.
Best regards,
UMO

Code 1: also can’t figure out freq over time graph
clc
clear
warning off
Fs = 8000; % Sampling frequency in hertz
ch = 1; % Number of channels–2 options–>1 (mono) or 2 (stereo)
datatype = ‘uint8’;
nbits = 16; % 8, 16, or 24
Nseconds = 5;

% To record audio data from an input device …
% … such as a microphone for processing in MATLAB
recorder1 = audiorecorder(Fs, nbits, ch, 1); % Use device ID 1 for first microphone

% Record audio to audiorecorder object,…
% … hold control until recording completes
recordblocking(recorder1, Nseconds);

disp(‘End of Recording.’);

% Store recorded audio
x1 = getaudiodata(recorder1);

% Write audio file
audiowrite(‘test1.wav’, x1, Fs);

% Calculate time vector
t1 = 0:1/Fs:(length(x1)-1)/Fs;

% Plot time domain signal
figure;
subplot(2, 1, 1);
plot(t1, x1, ‘LineWidth’, 1.5);
xlabel(‘Time (sec)’);
ylabel(‘Amplitude’);
title(‘Time Domain Plot of the Recorded Signal’);

% Stat Information
maxValue = max(x1);
minValue = min(x1);
meanValue = mean(x1);
stdValue = std(x1);
rmsValue = rms(x1); % root mean square

% Display statistical information
disp(‘Statistical Information:’)
disp([‘Max Value: ‘, num2str(maxValue)])
disp([‘Min Value: ‘, num2str(minValue)])
disp([‘Mean Value: ‘, num2str(meanValue)])
disp([‘Standard Deviation: ‘, num2str(stdValue)])
disp([‘RMS Value: ‘, num2str(rmsValue)])

% Plot time domain signal
%figure;
% subplot(2, 1, 2);
%plot(t2, x2, ‘LineWidth’, 1.5);
%xlabel(‘Time (sec)’);
%ylabel(‘Amplitude’);
%title(‘Time Domain Plot of the Recorded Signal mirco 2’);

% Calculate FFt
n1 = length(x1);
Y1 = fft(x1);
F1 = Fs/n1*(0:n1-1);

% Find the average frequency

freq = meanfreq( x1 ,Fs );
disp([‘Average frequency of the recorded sound: ‘, num2str(freq), ‘ Hz’]);

% Plot frequency domain signal
% subplot(2, 1, 2);
figure;
plot(F1, abs(Y1(:,1)), ‘LineWidth’, 1.5);
xlabel(‘Frequency (Hz)’);
ylabel(‘Amplitude’);
title(‘Frequency Domain Plot of the Audio Signal’);

Code 2:
clc
clear
close all
warning off

% Reading input signal
[file, path] = uigetfile(‘*.wav’, ‘Select a WAV file’);
filename = fullfile(path, file);
[input_signal, Fs] = audioread(filename);

% Create time vector
t = (0:length(input_signal)-1) / Fs;

% Plotting time-domain signal
figure;
plot(t, input_signal);
grid on
title(‘Time Domain Signal’, ‘FontName’, ‘Times New Roman’, ‘FontSize’, 14);
xlabel(‘Time (sec)’, ‘FontName’, ‘Times New Roman’, ‘FontSize’, 12);
ylabel(‘Amplitude’, ‘FontName’, ‘Times New Roman’, ‘FontSize’, 12);

% Stat Information
maxValue = max(input_signal);
minValue = min(input_signal);
meanValue = mean(input_signal);
stdValue = std(input_signal);
rmsValue = rms(input_signal); % root mean square

% Display statistical information
disp(‘Statistical Information:’)
disp([‘Max Value: ‘, num2str(maxValue)])
disp([‘Min Value: ‘, num2str(minValue)])
disp([‘Mean Value: ‘, num2str(meanValue)])
disp([‘Standard Deviation: ‘, num2str(stdValue)])
disp([‘RMS Value: ‘, num2str(rmsValue)])

% Compute FFT
N = length(input_signal);
v = fft(input_signal);
v = v(1:N/2+1); % Keep only the positive frequencies
f = (0:N/2) * Fs / N; % Frequency vector

% Find the average frequency
freq = meanfreq(input_signal, Fs);
disp([‘Average frequency of the recorded sound: ‘, num2str(freq), ‘ Hz’]);

% find avg frequency manually

tfreq = sum(abs(input_signal).^2);

% Display the result
disp([‘Total frequency domain energy: ‘, num2str(tfreq)])Hello everyone,
I am encountering an issue with calculating the average frequency in MATLAB. The average frequency result is unexpectedly high and varies with each execution, even though the audio input remains unchanged. Conversely, using the same audio in Python yields more consistent and reasonable results.
If anyone can identify the problem and help fix my MATLAB code, it would be greatly appreciated. Below are two versions of the code: the first records sound directly in MATLAB, and the second processes an existing audio file.
Thank you for your assistance.
Best regards,
UMO

Code 1: also can’t figure out freq over time graph
clc
clear
warning off
Fs = 8000; % Sampling frequency in hertz
ch = 1; % Number of channels–2 options–>1 (mono) or 2 (stereo)
datatype = ‘uint8’;
nbits = 16; % 8, 16, or 24
Nseconds = 5;

% To record audio data from an input device …
% … such as a microphone for processing in MATLAB
recorder1 = audiorecorder(Fs, nbits, ch, 1); % Use device ID 1 for first microphone

% Record audio to audiorecorder object,…
% … hold control until recording completes
recordblocking(recorder1, Nseconds);

disp(‘End of Recording.’);

% Store recorded audio
x1 = getaudiodata(recorder1);

% Write audio file
audiowrite(‘test1.wav’, x1, Fs);

% Calculate time vector
t1 = 0:1/Fs:(length(x1)-1)/Fs;

% Plot time domain signal
figure;
subplot(2, 1, 1);
plot(t1, x1, ‘LineWidth’, 1.5);
xlabel(‘Time (sec)’);
ylabel(‘Amplitude’);
title(‘Time Domain Plot of the Recorded Signal’);

% Stat Information
maxValue = max(x1);
minValue = min(x1);
meanValue = mean(x1);
stdValue = std(x1);
rmsValue = rms(x1); % root mean square

% Display statistical information
disp(‘Statistical Information:’)
disp([‘Max Value: ‘, num2str(maxValue)])
disp([‘Min Value: ‘, num2str(minValue)])
disp([‘Mean Value: ‘, num2str(meanValue)])
disp([‘Standard Deviation: ‘, num2str(stdValue)])
disp([‘RMS Value: ‘, num2str(rmsValue)])

% Plot time domain signal
%figure;
% subplot(2, 1, 2);
%plot(t2, x2, ‘LineWidth’, 1.5);
%xlabel(‘Time (sec)’);
%ylabel(‘Amplitude’);
%title(‘Time Domain Plot of the Recorded Signal mirco 2’);

% Calculate FFt
n1 = length(x1);
Y1 = fft(x1);
F1 = Fs/n1*(0:n1-1);

% Find the average frequency

freq = meanfreq( x1 ,Fs );
disp([‘Average frequency of the recorded sound: ‘, num2str(freq), ‘ Hz’]);

% Plot frequency domain signal
% subplot(2, 1, 2);
figure;
plot(F1, abs(Y1(:,1)), ‘LineWidth’, 1.5);
xlabel(‘Frequency (Hz)’);
ylabel(‘Amplitude’);
title(‘Frequency Domain Plot of the Audio Signal’);

Code 2:
clc
clear
close all
warning off

% Reading input signal
[file, path] = uigetfile(‘*.wav’, ‘Select a WAV file’);
filename = fullfile(path, file);
[input_signal, Fs] = audioread(filename);

% Create time vector
t = (0:length(input_signal)-1) / Fs;

% Plotting time-domain signal
figure;
plot(t, input_signal);
grid on
title(‘Time Domain Signal’, ‘FontName’, ‘Times New Roman’, ‘FontSize’, 14);
xlabel(‘Time (sec)’, ‘FontName’, ‘Times New Roman’, ‘FontSize’, 12);
ylabel(‘Amplitude’, ‘FontName’, ‘Times New Roman’, ‘FontSize’, 12);

% Stat Information
maxValue = max(input_signal);
minValue = min(input_signal);
meanValue = mean(input_signal);
stdValue = std(input_signal);
rmsValue = rms(input_signal); % root mean square

% Display statistical information
disp(‘Statistical Information:’)
disp([‘Max Value: ‘, num2str(maxValue)])
disp([‘Min Value: ‘, num2str(minValue)])
disp([‘Mean Value: ‘, num2str(meanValue)])
disp([‘Standard Deviation: ‘, num2str(stdValue)])
disp([‘RMS Value: ‘, num2str(rmsValue)])

% Compute FFT
N = length(input_signal);
v = fft(input_signal);
v = v(1:N/2+1); % Keep only the positive frequencies
f = (0:N/2) * Fs / N; % Frequency vector

% Find the average frequency
freq = meanfreq(input_signal, Fs);
disp([‘Average frequency of the recorded sound: ‘, num2str(freq), ‘ Hz’]);

% find avg frequency manually

tfreq = sum(abs(input_signal).^2);

% Display the result
disp([‘Total frequency domain energy: ‘, num2str(tfreq)]) Hello everyone,
I am encountering an issue with calculating the average frequency in MATLAB. The average frequency result is unexpectedly high and varies with each execution, even though the audio input remains unchanged. Conversely, using the same audio in Python yields more consistent and reasonable results.
If anyone can identify the problem and help fix my MATLAB code, it would be greatly appreciated. Below are two versions of the code: the first records sound directly in MATLAB, and the second processes an existing audio file.
Thank you for your assistance.
Best regards,
UMO

Code 1: also can’t figure out freq over time graph
clc
clear
warning off
Fs = 8000; % Sampling frequency in hertz
ch = 1; % Number of channels–2 options–>1 (mono) or 2 (stereo)
datatype = ‘uint8’;
nbits = 16; % 8, 16, or 24
Nseconds = 5;

% To record audio data from an input device …
% … such as a microphone for processing in MATLAB
recorder1 = audiorecorder(Fs, nbits, ch, 1); % Use device ID 1 for first microphone

% Record audio to audiorecorder object,…
% … hold control until recording completes
recordblocking(recorder1, Nseconds);

disp(‘End of Recording.’);

% Store recorded audio
x1 = getaudiodata(recorder1);

% Write audio file
audiowrite(‘test1.wav’, x1, Fs);

% Calculate time vector
t1 = 0:1/Fs:(length(x1)-1)/Fs;

% Plot time domain signal
figure;
subplot(2, 1, 1);
plot(t1, x1, ‘LineWidth’, 1.5);
xlabel(‘Time (sec)’);
ylabel(‘Amplitude’);
title(‘Time Domain Plot of the Recorded Signal’);

% Stat Information
maxValue = max(x1);
minValue = min(x1);
meanValue = mean(x1);
stdValue = std(x1);
rmsValue = rms(x1); % root mean square

% Display statistical information
disp(‘Statistical Information:’)
disp([‘Max Value: ‘, num2str(maxValue)])
disp([‘Min Value: ‘, num2str(minValue)])
disp([‘Mean Value: ‘, num2str(meanValue)])
disp([‘Standard Deviation: ‘, num2str(stdValue)])
disp([‘RMS Value: ‘, num2str(rmsValue)])

% Plot time domain signal
%figure;
% subplot(2, 1, 2);
%plot(t2, x2, ‘LineWidth’, 1.5);
%xlabel(‘Time (sec)’);
%ylabel(‘Amplitude’);
%title(‘Time Domain Plot of the Recorded Signal mirco 2’);

% Calculate FFt
n1 = length(x1);
Y1 = fft(x1);
F1 = Fs/n1*(0:n1-1);

% Find the average frequency

freq = meanfreq( x1 ,Fs );
disp([‘Average frequency of the recorded sound: ‘, num2str(freq), ‘ Hz’]);

% Plot frequency domain signal
% subplot(2, 1, 2);
figure;
plot(F1, abs(Y1(:,1)), ‘LineWidth’, 1.5);
xlabel(‘Frequency (Hz)’);
ylabel(‘Amplitude’);
title(‘Frequency Domain Plot of the Audio Signal’);

Code 2:
clc
clear
close all
warning off

% Reading input signal
[file, path] = uigetfile(‘*.wav’, ‘Select a WAV file’);
filename = fullfile(path, file);
[input_signal, Fs] = audioread(filename);

% Create time vector
t = (0:length(input_signal)-1) / Fs;

% Plotting time-domain signal
figure;
plot(t, input_signal);
grid on
title(‘Time Domain Signal’, ‘FontName’, ‘Times New Roman’, ‘FontSize’, 14);
xlabel(‘Time (sec)’, ‘FontName’, ‘Times New Roman’, ‘FontSize’, 12);
ylabel(‘Amplitude’, ‘FontName’, ‘Times New Roman’, ‘FontSize’, 12);

% Stat Information
maxValue = max(input_signal);
minValue = min(input_signal);
meanValue = mean(input_signal);
stdValue = std(input_signal);
rmsValue = rms(input_signal); % root mean square

% Display statistical information
disp(‘Statistical Information:’)
disp([‘Max Value: ‘, num2str(maxValue)])
disp([‘Min Value: ‘, num2str(minValue)])
disp([‘Mean Value: ‘, num2str(meanValue)])
disp([‘Standard Deviation: ‘, num2str(stdValue)])
disp([‘RMS Value: ‘, num2str(rmsValue)])

% Compute FFT
N = length(input_signal);
v = fft(input_signal);
v = v(1:N/2+1); % Keep only the positive frequencies
f = (0:N/2) * Fs / N; % Frequency vector

% Find the average frequency
freq = meanfreq(input_signal, Fs);
disp([‘Average frequency of the recorded sound: ‘, num2str(freq), ‘ Hz’]);

% find avg frequency manually

tfreq = sum(abs(input_signal).^2);

% Display the result
disp([‘Total frequency domain energy: ‘, num2str(tfreq)]) frequency, meanfreq, meanfrequency, frequencyovertime, graph, help MATLAB Answers — New Questions

​

Hi,
I am using the Symbolic Math Toolbox to calculate the analytical eigenvalues of a polynomial matrix A(z), that is generated in my physical use-case. Depending on the input parameters, the matrix can scale in size from 1×1 to any nxn.
If I configure my matrix to have a size nxn > 4×4, the symbolic math toolbox still produces analytical eigenvalues (i.e. a polynomials without the "root" expression). How does Matlab calculate the analytical Eigenvalues in this particular case?
According to an answer to my previous question: https://www.mathworks.com/matlabcentral/answers/2132636-how-does-matlabs-symbolic-math-toolbox-always-finds-an-analytical-eigendecomposition-for-arbitrary-p#answer_1478061, Matlab uses numerical methods to find the roots of the characteristic polynomial.
However, from my experience the symbolic toolbox does not provide an analytic expression (i.e. a polynomial), if numerical methods where used and the solution is purely numerical. So my question is how Matlab arrives at this result?
Does Matlab indeed use a numerical approximation?
Does Matlab do some "tricks" in the background to reformulate my matrix into some analytically solvable matrix?
I also have attached a copy of my Matrix in a 6×6 configuration and the corresponding result.
Note: the variable "y" in my matrix represents 1/z, but this shouldn’t make a difference.
My code does the following:
syms z y
A = A;
A_roots = eig(A);Hi,
I am using the Symbolic Math Toolbox to calculate the analytical eigenvalues of a polynomial matrix A(z), that is generated in my physical use-case. Depending on the input parameters, the matrix can scale in size from 1×1 to any nxn.
If I configure my matrix to have a size nxn > 4×4, the symbolic math toolbox still produces analytical eigenvalues (i.e. a polynomials without the "root" expression). How does Matlab calculate the analytical Eigenvalues in this particular case?
According to an answer to my previous question: https://www.mathworks.com/matlabcentral/answers/2132636-how-does-matlabs-symbolic-math-toolbox-always-finds-an-analytical-eigendecomposition-for-arbitrary-p#answer_1478061, Matlab uses numerical methods to find the roots of the characteristic polynomial.
However, from my experience the symbolic toolbox does not provide an analytic expression (i.e. a polynomial), if numerical methods where used and the solution is purely numerical. So my question is how Matlab arrives at this result?
Does Matlab indeed use a numerical approximation?
Does Matlab do some "tricks" in the background to reformulate my matrix into some analytically solvable matrix?
I also have attached a copy of my Matrix in a 6×6 configuration and the corresponding result.
Note: the variable "y" in my matrix represents 1/z, but this shouldn’t make a difference.
My code does the following:
syms z y
A = A;
A_roots = eig(A); Hi,
I am using the Symbolic Math Toolbox to calculate the analytical eigenvalues of a polynomial matrix A(z), that is generated in my physical use-case. Depending on the input parameters, the matrix can scale in size from 1×1 to any nxn.
If I configure my matrix to have a size nxn > 4×4, the symbolic math toolbox still produces analytical eigenvalues (i.e. a polynomials without the "root" expression). How does Matlab calculate the analytical Eigenvalues in this particular case?
According to an answer to my previous question: https://www.mathworks.com/matlabcentral/answers/2132636-how-does-matlabs-symbolic-math-toolbox-always-finds-an-analytical-eigendecomposition-for-arbitrary-p#answer_1478061, Matlab uses numerical methods to find the roots of the characteristic polynomial.
However, from my experience the symbolic toolbox does not provide an analytic expression (i.e. a polynomial), if numerical methods where used and the solution is purely numerical. So my question is how Matlab arrives at this result?
Does Matlab indeed use a numerical approximation?
Does Matlab do some "tricks" in the background to reformulate my matrix into some analytically solvable matrix?
I also have attached a copy of my Matrix in a 6×6 configuration and the corresponding result.
Note: the variable "y" in my matrix represents 1/z, but this shouldn’t make a difference.
My code does the following:
syms z y
A = A;
A_roots = eig(A); symbolic-math, polynomial-matrices, eigenvalues MATLAB Answers — New Questions

​

I have a user-created subclass Domain2d < fegeometry. The fegeometry class is a default class in MATLAB, and the inputs for the fegeometry constructor are not user-friendly. Part of the idea of the Domain2d subclass is that its constructor should take user-friendly inputs, translate them into the complex inputs needed for the fegeometry constructor, then call the fegeometry constructor. The way the code is currently written, the task of manipulating the simple inputs into complex inputs is like:
classdef Domain2d < fegeometry
properties
end

methods
function self = Domain2d(simple_inputs)

% manipulate simple_inputs to complex_inputs
…(code here)

% call superclass constructor
self@fegeometry(complex_inputs);

end
end
end
This is kludge-y, but it works, and substantial code has been written that uses the bar object. But now I have a good reason to want to rewrite the bar object like
classdef Domain2d < fegeometry
properties
end

methods
function self = Domain2d(simple_inputs)

complex_inputs = translateSimpleToComplex(self,simple_inputs);
self@fegeometry(complex_inputs);

end

function complex_inputs = translateSimpleToComplex(self,simple_inputs)
…
end
end
end
The above produces the error "Calling the superclass constructor ‘fegeometry’ after an object use or after a return statement is not supported."
How should I proceed?I have a user-created subclass Domain2d < fegeometry. The fegeometry class is a default class in MATLAB, and the inputs for the fegeometry constructor are not user-friendly. Part of the idea of the Domain2d subclass is that its constructor should take user-friendly inputs, translate them into the complex inputs needed for the fegeometry constructor, then call the fegeometry constructor. The way the code is currently written, the task of manipulating the simple inputs into complex inputs is like:
classdef Domain2d < fegeometry
properties
end

methods
function self = Domain2d(simple_inputs)

% manipulate simple_inputs to complex_inputs
…(code here)

% call superclass constructor
self@fegeometry(complex_inputs);

end
end
end
This is kludge-y, but it works, and substantial code has been written that uses the bar object. But now I have a good reason to want to rewrite the bar object like
classdef Domain2d < fegeometry
properties
end

methods
function self = Domain2d(simple_inputs)

complex_inputs = translateSimpleToComplex(self,simple_inputs);
self@fegeometry(complex_inputs);

end

function complex_inputs = translateSimpleToComplex(self,simple_inputs)
…
end
end
end
The above produces the error "Calling the superclass constructor ‘fegeometry’ after an object use or after a return statement is not supported."
How should I proceed? I have a user-created subclass Domain2d < fegeometry. The fegeometry class is a default class in MATLAB, and the inputs for the fegeometry constructor are not user-friendly. Part of the idea of the Domain2d subclass is that its constructor should take user-friendly inputs, translate them into the complex inputs needed for the fegeometry constructor, then call the fegeometry constructor. The way the code is currently written, the task of manipulating the simple inputs into complex inputs is like:
classdef Domain2d < fegeometry
properties
end

methods
function self = Domain2d(simple_inputs)

% manipulate simple_inputs to complex_inputs
…(code here)

% call superclass constructor
self@fegeometry(complex_inputs);

end
end
end
This is kludge-y, but it works, and substantial code has been written that uses the bar object. But now I have a good reason to want to rewrite the bar object like
classdef Domain2d < fegeometry
properties
end

methods
function self = Domain2d(simple_inputs)

complex_inputs = translateSimpleToComplex(self,simple_inputs);
self@fegeometry(complex_inputs);

end

function complex_inputs = translateSimpleToComplex(self,simple_inputs)
…
end
end
end
The above produces the error "Calling the superclass constructor ‘fegeometry’ after an object use or after a return statement is not supported."
How should I proceed? classes, inheritance, constructors MATLAB Answers — New Questions

​

I have a simple cos wave that has a period, in this case 6. I am offsetting the wave by an angular amount with phase. How can I use the fft function to recover back my initial phase offset? I tried converting the fourier transformed value with the highest amplitude (abs) which does correclty identify the period back to a phase using angle, but this never seems to work. If someone could enlighten me as to how to do this, I would be so grateful! (Edit: I would like to see how to correctly recover the original period as well)
n = 1e3;
a = linspace(0, 2*pi, n);
period = 6;
phase = rand * 2*pi;
f = rescale(cos((a-phase)*pr));I have a simple cos wave that has a period, in this case 6. I am offsetting the wave by an angular amount with phase. How can I use the fft function to recover back my initial phase offset? I tried converting the fourier transformed value with the highest amplitude (abs) which does correclty identify the period back to a phase using angle, but this never seems to work. If someone could enlighten me as to how to do this, I would be so grateful! (Edit: I would like to see how to correctly recover the original period as well)
n = 1e3;
a = linspace(0, 2*pi, n);
period = 6;
phase = rand * 2*pi;
f = rescale(cos((a-phase)*pr)); I have a simple cos wave that has a period, in this case 6. I am offsetting the wave by an angular amount with phase. How can I use the fft function to recover back my initial phase offset? I tried converting the fourier transformed value with the highest amplitude (abs) which does correclty identify the period back to a phase using angle, but this never seems to work. If someone could enlighten me as to how to do this, I would be so grateful! (Edit: I would like to see how to correctly recover the original period as well)
n = 1e3;
a = linspace(0, 2*pi, n);
period = 6;
phase = rand * 2*pi;
f = rescale(cos((a-phase)*pr)); fourier, fft, phase MATLAB Answers — New Questions

​

I am using MATLAB R2024a and anaconda v24.1.2. I am trying to install matlab.engine on a specific anaconda environment, but when I naviagte to the setup.py file in the matlabroot directory tree I get the error:
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptools_distutilscmd.py:66: SetuptoolsDeprecationWarning: setup.py install is deprecated.
!!
********************************************************************************
Please avoid running “setup.py“ directly.
Instead, use pypa/build, pypa/installer or other
standards-based tools.
See https://blog.ganssle.io/articles/2021/10/setup-py-deprecated.html for details.
********************************************************************************
!!
self.initialize_options()
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptools_distutilscmd.py:66: EasyInstallDeprecationWarning: easy_install command is deprecated.
!!
********************************************************************************
Please avoid running “setup.py“ and “easy_install“.
Instead, use pypa/build, pypa/installer or other
standards-based tools.
See https://github.com/pypa/setuptools/issues/917 for details.
********************************************************************************
!!
self.initialize_options()
TEST FAILED: C:Userssteve.condapkgsLibsite-packages does NOT support .pth files
bad install directory or PYTHONPATH
You are attempting to install a package to a directory that is not
on PYTHONPATH and which Python does not read ".pth" files from. The
installation directory you specified (via –install-dir, –prefix, or
the distutils default setting) was:
C:Userssteve.condapkgsLibsite-packages
and your PYTHONPATH environment variable currently contains:
”
Here are some of your options for correcting the problem:
* You can choose a different installation directory, i.e., one that is
on PYTHONPATH or supports .pth files
* You can add the installation directory to the PYTHONPATH environment
variable. (It must then also be on PYTHONPATH whenever you run
Python and want to use the package(s) you are installing.)
* You can set up the installation directory to support ".pth" files by
using one of the approaches described here:
https://setuptools.pypa.io/en/latest/deprecated/easy_install.html#custom-installation-locations
Please make the appropriate changes for your system and try again.
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptoolscommandsdist.py:117: SetuptoolsDeprecationWarning: `build_py` command does not inherit from setuptools’ `build_py`.
!!
********************************************************************************
Custom ‘build_py’ does not implement ‘get_data_files_without_manifest’.
Please extend command classes from setuptools instead of distutils.
See https://peps.python.org/pep-0632/ for details.
********************************************************************************
!!
self._add_data_files(self._safe_data_files(build_py))
zip_safe flag not set; analyzing archive contents…
matlab.__pycache__.__init__.cpython-311: module references __file__
matlab.__pycache__.__init__.cpython-311: module references __path__
matlab.engine.__pycache__.__init__.cpython-311: module references __file__
(3d_model_analysis) C:Program FilesMATLABR2024aexternenginespython>python setup.py install –prefix "C:/Users/steve/.conda/pkgs"
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptools_distutilscmd.py:66: SetuptoolsDeprecationWarning: setup.py install is deprecated.
!!
********************************************************************************
Please avoid running “setup.py“ directly.
Instead, use pypa/build, pypa/installer or other
standards-based tools.
See https://blog.ganssle.io/articles/2021/10/setup-py-deprecated.html for details.
********************************************************************************
!!
self.initialize_options()
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptools_distutilscmd.py:66: EasyInstallDeprecationWarning: easy_install command is deprecated.
!!
********************************************************************************
Please avoid running “setup.py“ and “easy_install“.
Instead, use pypa/build, pypa/installer or other
standards-based tools.
See https://github.com/pypa/setuptools/issues/917 for details.
********************************************************************************
!!
self.initialize_options()
TEST FAILED: C:Userssteve.condapkgsLibsite-packages does NOT support .pth files
bad install directory or PYTHONPATH
You are attempting to install a package to a directory that is not
on PYTHONPATH and which Python does not read ".pth" files from. The
installation directory you specified (via –install-dir, –prefix, or
the distutils default setting) was:
C:Userssteve.condapkgsLibsite-packages
and your PYTHONPATH environment variable currently contains:
”
Here are some of your options for correcting the problem:
* You can choose a different installation directory, i.e., one that is
on PYTHONPATH or supports .pth files
* You can add the installation directory to the PYTHONPATH environment
variable. (It must then also be on PYTHONPATH whenever you run
Python and want to use the package(s) you are installing.)
* You can set up the installation directory to support ".pth" files by
using one of the approaches described here:
https://setuptools.pypa.io/en/latest/deprecated/easy_install.html#custom-installation-locations
Please make the appropriate changes for your system and try again.
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptoolscommandsdist.py:117: SetuptoolsDeprecationWarning: `build_py` command does not inherit from setuptools’ `build_py`.
!!
********************************************************************************
Custom ‘build_py’ does not implement ‘get_data_files_without_manifest’.
Please extend command classes from setuptools instead of distutils.
See https://peps.python.org/pep-0632/ for details.
********************************************************************************
!!
self._add_data_files(self._safe_data_files(build_py))
zip_safe flag not set; analyzing archive contents…
matlab.__pycache__.__init__.cpython-311: module references __file__
matlab.__pycache__.__init__.cpython-311: module references __path__
matlab.engine.__pycache__.__init__.cpython-311: module references __file__I am using MATLAB R2024a and anaconda v24.1.2. I am trying to install matlab.engine on a specific anaconda environment, but when I naviagte to the setup.py file in the matlabroot directory tree I get the error:
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptools_distutilscmd.py:66: SetuptoolsDeprecationWarning: setup.py install is deprecated.
!!
********************************************************************************
Please avoid running “setup.py“ directly.
Instead, use pypa/build, pypa/installer or other
standards-based tools.
See https://blog.ganssle.io/articles/2021/10/setup-py-deprecated.html for details.
********************************************************************************
!!
self.initialize_options()
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptools_distutilscmd.py:66: EasyInstallDeprecationWarning: easy_install command is deprecated.
!!
********************************************************************************
Please avoid running “setup.py“ and “easy_install“.
Instead, use pypa/build, pypa/installer or other
standards-based tools.
See https://github.com/pypa/setuptools/issues/917 for details.
********************************************************************************
!!
self.initialize_options()
TEST FAILED: C:Userssteve.condapkgsLibsite-packages does NOT support .pth files
bad install directory or PYTHONPATH
You are attempting to install a package to a directory that is not
on PYTHONPATH and which Python does not read ".pth" files from. The
installation directory you specified (via –install-dir, –prefix, or
the distutils default setting) was:
C:Userssteve.condapkgsLibsite-packages
and your PYTHONPATH environment variable currently contains:
”
Here are some of your options for correcting the problem:
* You can choose a different installation directory, i.e., one that is
on PYTHONPATH or supports .pth files
* You can add the installation directory to the PYTHONPATH environment
variable. (It must then also be on PYTHONPATH whenever you run
Python and want to use the package(s) you are installing.)
* You can set up the installation directory to support ".pth" files by
using one of the approaches described here:
https://setuptools.pypa.io/en/latest/deprecated/easy_install.html#custom-installation-locations
Please make the appropriate changes for your system and try again.
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptoolscommandsdist.py:117: SetuptoolsDeprecationWarning: `build_py` command does not inherit from setuptools’ `build_py`.
!!
********************************************************************************
Custom ‘build_py’ does not implement ‘get_data_files_without_manifest’.
Please extend command classes from setuptools instead of distutils.
See https://peps.python.org/pep-0632/ for details.
********************************************************************************
!!
self._add_data_files(self._safe_data_files(build_py))
zip_safe flag not set; analyzing archive contents…
matlab.__pycache__.__init__.cpython-311: module references __file__
matlab.__pycache__.__init__.cpython-311: module references __path__
matlab.engine.__pycache__.__init__.cpython-311: module references __file__
(3d_model_analysis) C:Program FilesMATLABR2024aexternenginespython>python setup.py install –prefix "C:/Users/steve/.conda/pkgs"
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptools_distutilscmd.py:66: SetuptoolsDeprecationWarning: setup.py install is deprecated.
!!
********************************************************************************
Please avoid running “setup.py“ directly.
Instead, use pypa/build, pypa/installer or other
standards-based tools.
See https://blog.ganssle.io/articles/2021/10/setup-py-deprecated.html for details.
********************************************************************************
!!
self.initialize_options()
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptools_distutilscmd.py:66: EasyInstallDeprecationWarning: easy_install command is deprecated.
!!
********************************************************************************
Please avoid running “setup.py“ and “easy_install“.
Instead, use pypa/build, pypa/installer or other
standards-based tools.
See https://github.com/pypa/setuptools/issues/917 for details.
********************************************************************************
!!
self.initialize_options()
TEST FAILED: C:Userssteve.condapkgsLibsite-packages does NOT support .pth files
bad install directory or PYTHONPATH
You are attempting to install a package to a directory that is not
on PYTHONPATH and which Python does not read ".pth" files from. The
installation directory you specified (via –install-dir, –prefix, or
the distutils default setting) was:
C:Userssteve.condapkgsLibsite-packages
and your PYTHONPATH environment variable currently contains:
”
Here are some of your options for correcting the problem:
* You can choose a different installation directory, i.e., one that is
on PYTHONPATH or supports .pth files
* You can add the installation directory to the PYTHONPATH environment
variable. (It must then also be on PYTHONPATH whenever you run
Python and want to use the package(s) you are installing.)
* You can set up the installation directory to support ".pth" files by
using one of the approaches described here:
https://setuptools.pypa.io/en/latest/deprecated/easy_install.html#custom-installation-locations
Please make the appropriate changes for your system and try again.
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptoolscommandsdist.py:117: SetuptoolsDeprecationWarning: `build_py` command does not inherit from setuptools’ `build_py`.
!!
********************************************************************************
Custom ‘build_py’ does not implement ‘get_data_files_without_manifest’.
Please extend command classes from setuptools instead of distutils.
See https://peps.python.org/pep-0632/ for details.
********************************************************************************
!!
self._add_data_files(self._safe_data_files(build_py))
zip_safe flag not set; analyzing archive contents…
matlab.__pycache__.__init__.cpython-311: module references __file__
matlab.__pycache__.__init__.cpython-311: module references __path__
matlab.engine.__pycache__.__init__.cpython-311: module references __file__ I am using MATLAB R2024a and anaconda v24.1.2. I am trying to install matlab.engine on a specific anaconda environment, but when I naviagte to the setup.py file in the matlabroot directory tree I get the error:
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptools_distutilscmd.py:66: SetuptoolsDeprecationWarning: setup.py install is deprecated.
!!
********************************************************************************
Please avoid running “setup.py“ directly.
Instead, use pypa/build, pypa/installer or other
standards-based tools.
See https://blog.ganssle.io/articles/2021/10/setup-py-deprecated.html for details.
********************************************************************************
!!
self.initialize_options()
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptools_distutilscmd.py:66: EasyInstallDeprecationWarning: easy_install command is deprecated.
!!
********************************************************************************
Please avoid running “setup.py“ and “easy_install“.
Instead, use pypa/build, pypa/installer or other
standards-based tools.
See https://github.com/pypa/setuptools/issues/917 for details.
********************************************************************************
!!
self.initialize_options()
TEST FAILED: C:Userssteve.condapkgsLibsite-packages does NOT support .pth files
bad install directory or PYTHONPATH
You are attempting to install a package to a directory that is not
on PYTHONPATH and which Python does not read ".pth" files from. The
installation directory you specified (via –install-dir, –prefix, or
the distutils default setting) was:
C:Userssteve.condapkgsLibsite-packages
and your PYTHONPATH environment variable currently contains:
”
Here are some of your options for correcting the problem:
* You can choose a different installation directory, i.e., one that is
on PYTHONPATH or supports .pth files
* You can add the installation directory to the PYTHONPATH environment
variable. (It must then also be on PYTHONPATH whenever you run
Python and want to use the package(s) you are installing.)
* You can set up the installation directory to support ".pth" files by
using one of the approaches described here:
https://setuptools.pypa.io/en/latest/deprecated/easy_install.html#custom-installation-locations
Please make the appropriate changes for your system and try again.
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptoolscommandsdist.py:117: SetuptoolsDeprecationWarning: `build_py` command does not inherit from setuptools’ `build_py`.
!!
********************************************************************************
Custom ‘build_py’ does not implement ‘get_data_files_without_manifest’.
Please extend command classes from setuptools instead of distutils.
See https://peps.python.org/pep-0632/ for details.
********************************************************************************
!!
self._add_data_files(self._safe_data_files(build_py))
zip_safe flag not set; analyzing archive contents…
matlab.__pycache__.__init__.cpython-311: module references __file__
matlab.__pycache__.__init__.cpython-311: module references __path__
matlab.engine.__pycache__.__init__.cpython-311: module references __file__
(3d_model_analysis) C:Program FilesMATLABR2024aexternenginespython>python setup.py install –prefix "C:/Users/steve/.conda/pkgs"
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptools_distutilscmd.py:66: SetuptoolsDeprecationWarning: setup.py install is deprecated.
!!
********************************************************************************
Please avoid running “setup.py“ directly.
Instead, use pypa/build, pypa/installer or other
standards-based tools.
See https://blog.ganssle.io/articles/2021/10/setup-py-deprecated.html for details.
********************************************************************************
!!
self.initialize_options()
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptools_distutilscmd.py:66: EasyInstallDeprecationWarning: easy_install command is deprecated.
!!
********************************************************************************
Please avoid running “setup.py“ and “easy_install“.
Instead, use pypa/build, pypa/installer or other
standards-based tools.
See https://github.com/pypa/setuptools/issues/917 for details.
********************************************************************************
!!
self.initialize_options()
TEST FAILED: C:Userssteve.condapkgsLibsite-packages does NOT support .pth files
bad install directory or PYTHONPATH
You are attempting to install a package to a directory that is not
on PYTHONPATH and which Python does not read ".pth" files from. The
installation directory you specified (via –install-dir, –prefix, or
the distutils default setting) was:
C:Userssteve.condapkgsLibsite-packages
and your PYTHONPATH environment variable currently contains:
”
Here are some of your options for correcting the problem:
* You can choose a different installation directory, i.e., one that is
on PYTHONPATH or supports .pth files
* You can add the installation directory to the PYTHONPATH environment
variable. (It must then also be on PYTHONPATH whenever you run
Python and want to use the package(s) you are installing.)
* You can set up the installation directory to support ".pth" files by
using one of the approaches described here:
https://setuptools.pypa.io/en/latest/deprecated/easy_install.html#custom-installation-locations
Please make the appropriate changes for your system and try again.
C:Userssteve.condaenvs3d_model_analysisLibsite-packagessetuptoolscommandsdist.py:117: SetuptoolsDeprecationWarning: `build_py` command does not inherit from setuptools’ `build_py`.
!!
********************************************************************************
Custom ‘build_py’ does not implement ‘get_data_files_without_manifest’.
Please extend command classes from setuptools instead of distutils.
See https://peps.python.org/pep-0632/ for details.
********************************************************************************
!!
self._add_data_files(self._safe_data_files(build_py))
zip_safe flag not set; analyzing archive contents…
matlab.__pycache__.__init__.cpython-311: module references __file__
matlab.__pycache__.__init__.cpython-311: module references __path__
matlab.engine.__pycache__.__init__.cpython-311: module references __file__ matlab.engine, python, matlab MATLAB Answers — New Questions

​