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Cannot echo Topics from Simulink in ROS on WSL2

/ 2024-06-12 / Matlab

I’m troubling in connecting Simulink and Unreal Engine through ROS on WSL2.
I want to send some messages from Simulink to UE (ROS Integration) using ROS Topics, but the topics from Simulink cannot be subscribed. (Actually the topic itself is subscribed, but no message is coming.)
My environment is as follows:
MATLAB R2024a + ROS Toolbox
Unreal Engine 5.1.1 (+ ROS Integration)
Ubuntu 20.04 on WSL2
ROS Noetic
I have confirmed the ROS communications below:
Simulink to the same Simulink: succes
Simulink to the other Simulink on the same computer: partly success (✔A→B, while ✘B→A. I suspected that the same port cannot be used for both publishing and subscribing, but alternating their roles did not work.)
Simulink to ROS: failed (The topics can be found by rostopic list, but I couldn’t rostopic echo.)
Simulink to UE: failed
UE to ROS: success (only String messages)
UE to Simulink: success (only String messages)
Regarding to the rostopic list, the rosnode info /SimulinkSystem_xxxxx (the node created by Simulink) response says that the connection to the node is failed.
I searched for the similar issues on internet and it may be caused by that the hostname cannot be resolved by ROS.
I have tried to set the environment variables so that they are not "localhost" nor "127.0.0.1", but it did not work. (When doing it, I could not connect to the ROS master.)

Could anyone figure out what is the true problem(s), and how to solve it?
Thank youI’m troubling in connecting Simulink and Unreal Engine through ROS on WSL2.
I want to send some messages from Simulink to UE (ROS Integration) using ROS Topics, but the topics from Simulink cannot be subscribed. (Actually the topic itself is subscribed, but no message is coming.)
My environment is as follows:
MATLAB R2024a + ROS Toolbox
Unreal Engine 5.1.1 (+ ROS Integration)
Ubuntu 20.04 on WSL2
ROS Noetic
I have confirmed the ROS communications below:
Simulink to the same Simulink: succes
Simulink to the other Simulink on the same computer: partly success (✔A→B, while ✘B→A. I suspected that the same port cannot be used for both publishing and subscribing, but alternating their roles did not work.)
Simulink to ROS: failed (The topics can be found by rostopic list, but I couldn’t rostopic echo.)
Simulink to UE: failed
UE to ROS: success (only String messages)
UE to Simulink: success (only String messages)
Regarding to the rostopic list, the rosnode info /SimulinkSystem_xxxxx (the node created by Simulink) response says that the connection to the node is failed.
I searched for the similar issues on internet and it may be caused by that the hostname cannot be resolved by ROS.
I have tried to set the environment variables so that they are not "localhost" nor "127.0.0.1", but it did not work. (When doing it, I could not connect to the ROS master.)

Could anyone figure out what is the true problem(s), and how to solve it?
Thank you I’m troubling in connecting Simulink and Unreal Engine through ROS on WSL2.
I want to send some messages from Simulink to UE (ROS Integration) using ROS Topics, but the topics from Simulink cannot be subscribed. (Actually the topic itself is subscribed, but no message is coming.)
My environment is as follows:
MATLAB R2024a + ROS Toolbox
Unreal Engine 5.1.1 (+ ROS Integration)
Ubuntu 20.04 on WSL2
ROS Noetic
I have confirmed the ROS communications below:
Simulink to the same Simulink: succes
Simulink to the other Simulink on the same computer: partly success (✔A→B, while ✘B→A. I suspected that the same port cannot be used for both publishing and subscribing, but alternating their roles did not work.)
Simulink to ROS: failed (The topics can be found by rostopic list, but I couldn’t rostopic echo.)
Simulink to UE: failed
UE to ROS: success (only String messages)
UE to Simulink: success (only String messages)
Regarding to the rostopic list, the rosnode info /SimulinkSystem_xxxxx (the node created by Simulink) response says that the connection to the node is failed.
I searched for the similar issues on internet and it may be caused by that the hostname cannot be resolved by ROS.
I have tried to set the environment variables so that they are not "localhost" nor "127.0.0.1", but it did not work. (When doing it, I could not connect to the ROS master.)

Could anyone figure out what is the true problem(s), and how to solve it?
Thank you matlab, simulink, ros, wsl2, noetic MATLAB Answers — New Questions

solving nonlinear wave equation

/ 2024-06-12 / Matlab

I need to solve this PDE below.

This is quite similar to the Burgers’ equation. However, I can’t understand how to get the exact solution to this equation. Please give an explicit solution to a given initial condition. Any initial condition is fine, just as long as the explicit solution is given. I will use it to check if my FDM code is correct.
In addition, if anyone has the code to solving this equation numerically, please post it here.
Thanks in advance!

below is my code.

for i = 2:(step(1)+1) % t
for j = 2:(step(2)+1) % x
rho(i, j) = rho(i-1, j) – v_max*(1-2*(rho(i-1, j)/rho_max))*(dt/dx)*(rho(i-1, j) – rho(i-1, j-1));
end
end

%———– set up —————

tspan = [0, 3]; % t
xspan = [-10, 10]; % x
step = [1000, 1000]; % step(1) : t, step(2) : x

t_values = linspace(tspan(1), tspan(2), step(1)+1);
x_values = linspace(xspan(1), xspan(2), step(2)+1);
v_max = 5; rho_max = 5; % vmax, rhomax

dt = (tspan(2) – tspan(1)) / step(1);
dx = (xspan(2) – xspan(1)) / step(2);

rho = zeros(step(1)+1, step(2)+1);
rhoo = zeros(step(1)+1, step(2)+1);

for j = 1:(step(1)+1)
rho(1, j) = 1/(1 + exp(j*dt));
end

%————- (FDM) ————-

for i = 2:(step(1)+1) % t
for j = 2:(step(2)+1) % x
rho(i, j) = rho(i-1, j) – v_max*(1-2*(rho(i-1, j)/rho_max))*(dt/dx)*(rho(i-1, j) – rho(i-1, j-1));
end
end

% for i = 1:(step(1)+1)
% for j = 1:(step(2)+1)
% rhoo(i, j) =
% end
% end

%———— animation ————–

filename = ‘animation.gif’;

figure;

for i = 1:(step(1)+1)
plot(x_values, rho(i, :));
xlabel(‘Position’);
ylabel(‘Density’);
title([‘Time = ‘, num2str(t_values(i))]);
drawnow;

frame = getframe(gcf);
img = frame2im(frame);
[imind, cm] = rgb2ind(img, 256);

if i == 1
imwrite(imind, cm, filename, ‘gif’, ‘Loopcount’, inf, ‘DelayTime’, dt);
else
imwrite(imind, cm, filename, ‘gif’, ‘WriteMode’, ‘append’, ‘DelayTime’, dt);
end
endI need to solve this PDE below.

below is my code.

for i = 2:(step(1)+1) % t
for j = 2:(step(2)+1) % x
rho(i, j) = rho(i-1, j) – v_max*(1-2*(rho(i-1, j)/rho_max))*(dt/dx)*(rho(i-1, j) – rho(i-1, j-1));
end
end

%———– set up —————

tspan = [0, 3]; % t
xspan = [-10, 10]; % x
step = [1000, 1000]; % step(1) : t, step(2) : x

t_values = linspace(tspan(1), tspan(2), step(1)+1);
x_values = linspace(xspan(1), xspan(2), step(2)+1);
v_max = 5; rho_max = 5; % vmax, rhomax

dt = (tspan(2) – tspan(1)) / step(1);
dx = (xspan(2) – xspan(1)) / step(2);

rho = zeros(step(1)+1, step(2)+1);
rhoo = zeros(step(1)+1, step(2)+1);

for j = 1:(step(1)+1)
rho(1, j) = 1/(1 + exp(j*dt));
end

%————- (FDM) ————-

for i = 2:(step(1)+1) % t
for j = 2:(step(2)+1) % x
rho(i, j) = rho(i-1, j) – v_max*(1-2*(rho(i-1, j)/rho_max))*(dt/dx)*(rho(i-1, j) – rho(i-1, j-1));
end
end

% for i = 1:(step(1)+1)
% for j = 1:(step(2)+1)
% rhoo(i, j) =
% end
% end

%———— animation ————–

filename = ‘animation.gif’;

figure;

for i = 1:(step(1)+1)
plot(x_values, rho(i, :));
xlabel(‘Position’);
ylabel(‘Density’);
title([‘Time = ‘, num2str(t_values(i))]);
drawnow;

frame = getframe(gcf);
img = frame2im(frame);
[imind, cm] = rgb2ind(img, 256);

below is my code.

for i = 2:(step(1)+1) % t
for j = 2:(step(2)+1) % x
rho(i, j) = rho(i-1, j) – v_max*(1-2*(rho(i-1, j)/rho_max))*(dt/dx)*(rho(i-1, j) – rho(i-1, j-1));
end
end

%———– set up —————

tspan = [0, 3]; % t
xspan = [-10, 10]; % x
step = [1000, 1000]; % step(1) : t, step(2) : x

t_values = linspace(tspan(1), tspan(2), step(1)+1);
x_values = linspace(xspan(1), xspan(2), step(2)+1);
v_max = 5; rho_max = 5; % vmax, rhomax

dt = (tspan(2) – tspan(1)) / step(1);
dx = (xspan(2) – xspan(1)) / step(2);

rho = zeros(step(1)+1, step(2)+1);
rhoo = zeros(step(1)+1, step(2)+1);

for j = 1:(step(1)+1)
rho(1, j) = 1/(1 + exp(j*dt));
end

%————- (FDM) ————-

for i = 2:(step(1)+1) % t
for j = 2:(step(2)+1) % x
rho(i, j) = rho(i-1, j) – v_max*(1-2*(rho(i-1, j)/rho_max))*(dt/dx)*(rho(i-1, j) – rho(i-1, j-1));
end
end

% for i = 1:(step(1)+1)
% for j = 1:(step(2)+1)
% rhoo(i, j) =
% end
% end

%———— animation ————–

filename = ‘animation.gif’;

figure;

for i = 1:(step(1)+1)
plot(x_values, rho(i, :));
xlabel(‘Position’);
ylabel(‘Density’);
title([‘Time = ‘, num2str(t_values(i))]);
drawnow;

frame = getframe(gcf);
img = frame2im(frame);
[imind, cm] = rgb2ind(img, 256);

if i == 1
imwrite(imind, cm, filename, ‘gif’, ‘Loopcount’, inf, ‘DelayTime’, dt);
else
imwrite(imind, cm, filename, ‘gif’, ‘WriteMode’, ‘append’, ‘DelayTime’, dt);
end
end pde MATLAB Answers — New Questions

how to Create random signal

/ 2024-06-12 / Matlab

random signal how torandom signal how to random signal how to MATLAB Answers — New Questions

USRP X310 HDL coder

/ 2024-06-12 / Matlab

Does HDL Coder support USRP X310?Does HDL Coder support USRP X310? Does HDL Coder support USRP X310? x310, hdl coder, usrp MATLAB Answers — New Questions

Multi-thread parsing and loading thousands of csv files

/ 2024-06-12 / Matlab

I have a folder with 2500 csv files, each 15MB each. I currently have a script that reads each csv into a cell array container as follows at the bottom.
Unfortunately this serial process takes a very long time to open each csv one by one.
Ideally I would like to multi-thread or open multiple csv files in parallel and save them into either their own set of cell arrays per ‘thread’ and later combine and sort them, or into one big cell array as it is currently.

%% IMPORT FILES

directory = ‘\headnodeuserdataGeorgeANSTOANSTO Day 2DataD14’;

datafiles = dir(append(directory,’*.csv’));
N=length(datafiles);
a = 0;
data = cell(1,N);
f = waitbar(a,’Importing Data…’);

for i = 1:N

data{i} = read_csv(strcat(datafiles(i).folder, ”, datafiles(i).name));
waitbar(i/N,f);
end
waitbar(1,f);
close(f);I have a folder with 2500 csv files, each 15MB each. I currently have a script that reads each csv into a cell array container as follows at the bottom.
Unfortunately this serial process takes a very long time to open each csv one by one.
Ideally I would like to multi-thread or open multiple csv files in parallel and save them into either their own set of cell arrays per ‘thread’ and later combine and sort them, or into one big cell array as it is currently.

%% IMPORT FILES

directory = ‘\headnodeuserdataGeorgeANSTOANSTO Day 2DataD14’;

datafiles = dir(append(directory,’*.csv’));
N=length(datafiles);
a = 0;
data = cell(1,N);
f = waitbar(a,’Importing Data…’);

for i = 1:N

data{i} = read_csv(strcat(datafiles(i).folder, ”, datafiles(i).name));
waitbar(i/N,f);
end
waitbar(1,f);
close(f); I have a folder with 2500 csv files, each 15MB each. I currently have a script that reads each csv into a cell array container as follows at the bottom.
Unfortunately this serial process takes a very long time to open each csv one by one.
Ideally I would like to multi-thread or open multiple csv files in parallel and save them into either their own set of cell arrays per ‘thread’ and later combine and sort them, or into one big cell array as it is currently.

%% IMPORT FILES

directory = ‘\headnodeuserdataGeorgeANSTOANSTO Day 2DataD14’;

datafiles = dir(append(directory,’*.csv’));
N=length(datafiles);
a = 0;
data = cell(1,N);
f = waitbar(a,’Importing Data…’);

for i = 1:N

data{i} = read_csv(strcat(datafiles(i).folder, ”, datafiles(i).name));
waitbar(i/N,f);
end
waitbar(1,f);
close(f); multi-thread, csv, file, file processing, speed, file handling, file import, data import, multiple, parsing, parallel, parallel computing MATLAB Answers — New Questions

Missing pulse with variable phase shift and configuring action qualifier

/ 2024-06-12 / Matlab

Hello,
I am using simulink to program c2000 TMS320F28379D microcontroller to test a dc-ac converter. I have a variable phase-shift input to the epwm. My TBPRD is 330 and the phase shift counter value can vary from -165 to 165 for up count mode. I am having issue with missing pulses near zero crossing. I posted this question on TI forum and got a suggestion to implement a trigger to check if TBCTR is less than CMPA and the TBPHS value is greater than CMPA. Below is the link for the link for the question I asked and the response. I see that there is a way to specify software synchronization through input port. However, I am not sure how to configure TBCTR and input the suggested logic in simulink.

The suggested logic is toselect EPWMxSYNC as the T1 event source and then set the action taken on T1-up to be setting the EPWM2A high. In this way, the action from a T1-up event would supplement what the missing CMPA(up) = 1000 action would have done.
Keep in mind that when these conditions are not true, the T1-up/down events need to be disabled to prevent it from affecting your desired duty cycle. Let me know if you have further questions here or have made any other progress.

How can I implement this logic in the epwm to handle these missing pulses?
Question I posted on TI forum
https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1372906/tms320f28379d-tms320f28379d-missing-pulses-with-variable-phase-shift

TI forum response
https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1312604/tms320f28379d-tms320f28379d-phase-shift-pwm-missing-pulse

I have also attached the simulink file. Would it be possible to check if my epwm configurations are correct? I have a missing pulse near the zero crossing of ac line voltage since a sharp phase shift transition happens there.

Thank you in advance.Hello,
I am using simulink to program c2000 TMS320F28379D microcontroller to test a dc-ac converter. I have a variable phase-shift input to the epwm. My TBPRD is 330 and the phase shift counter value can vary from -165 to 165 for up count mode. I am having issue with missing pulses near zero crossing. I posted this question on TI forum and got a suggestion to implement a trigger to check if TBCTR is less than CMPA and the TBPHS value is greater than CMPA. Below is the link for the link for the question I asked and the response. I see that there is a way to specify software synchronization through input port. However, I am not sure how to configure TBCTR and input the suggested logic in simulink.

TI forum response
https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1312604/tms320f28379d-tms320f28379d-phase-shift-pwm-missing-pulse

Thank you in advance. Hello,
I am using simulink to program c2000 TMS320F28379D microcontroller to test a dc-ac converter. I have a variable phase-shift input to the epwm. My TBPRD is 330 and the phase shift counter value can vary from -165 to 165 for up count mode. I am having issue with missing pulses near zero crossing. I posted this question on TI forum and got a suggestion to implement a trigger to check if TBCTR is less than CMPA and the TBPHS value is greater than CMPA. Below is the link for the link for the question I asked and the response. I see that there is a way to specify software synchronization through input port. However, I am not sure how to configure TBCTR and input the suggested logic in simulink.

TI forum response
https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1312604/tms320f28379d-tms320f28379d-phase-shift-pwm-missing-pulse

Thank you in advance. missing pulse, trigger MATLAB Answers — New Questions

ROS2, MATLAB, GAZEBO.

/ 2024-06-12 / Matlab

I’m using ros2/Matlab and need the tranformations in a chart. How could I do that.I’m using ros2/Matlab and need the tranformations in a chart. How could I do that. I’m using ros2/Matlab and need the tranformations in a chart. How could I do that. ros2 MATLAB Answers — New Questions

Confidence interval calculation. Cannot compute confidence interval for imaginary values.

/ 2024-06-12 / Matlab

clear; clc

load Steady_State_Data.mat % this contains the wavelength of light and absorbance of substrate and sample

%% Preamble

% Fundamental constants
h = 4.0135667696*10^-15; % units: eV/ Hz
c = 3*10^8; % SI units

% Clean up of data to select range of values
Absorbance = log10(T_substrate./T_sample);
E = (h*c./(Lambda*10^-9));
e = E >= 0 & E <= 2.0; % returns boolean value of the indices that satisfies the logical condition defined above
A = find(e); % gives indices that are non-zero
N = length(A); % no. of elements that are non-zero
n = length(E) + 1;

% Data for fitting
E_p = E(n-N:167);
Abs = Absorbance(n-N:167) – min(Absorbance);
% Abs = Absorbance(n-N:167);

% Fitting function
function F = EM_SS(p, e_p)
for i = 1:numel(e_p)
E_p = e_p(i);
F(i) = p(1)*(2*pi*sqrt(p(4))/E_p)*(1/p(6))*…
(integral(@(E)sech(((E_p – E)./p(6)))*(1 + 10*p(5)*(E – p(3)) + …
126*(p(5))^2*(E – p(3))^2)/(1 – exp(-2*pi*sqrt(p(4)/(E – p(3))))), p(3), Inf, ‘ArrayValued’, 1)) + …
p(2)*(2*pi*p(4)^3/2)*1/p(6)*(…
(1/1^3)*sech((E_p – p(3) + p(4)/1^2)./p(6)) + …
(1/2^3)*sech((E_p – p(3) + p(4)/2^2)./p(6)) + …
(1/3^3)*sech((E_p – p(3) + p(4)/3^2)./p(6)) + …
(1/4^3)*sech((E_p – p(3) + p(4)/4^2)./p(6)) + …
(1/5^3)*sech((E_p – p(3) + p(4)/5^2)./p(6)) + …
(1/6^3)*sech((E_p – p(3) + p(4)/6^2)./p(6)) + …
(1/7^3)*sech((E_p – p(3) + p(4)/7^2)./p(6)));
end
F = F(:);
end

%% Curve fitting options

% Initial parameter guess and bounds
lb = [0,0,0,0,0,0]; ub = [Inf, Inf, 1.65, 0.03, Inf, Inf];
p0 = [0.13, 0.11, 1.4, 0.025, 0.12, 0.035]; % refer to the next line for their order
% p0 = [A1, A2, Eg, Eb, R, g]

% lsqcurvefit and choose between different algorithm that lsqcurvefit employs (3C1, comment those lines that are not choosen and uncomment the line that is choosen, if not, matlab will take the last line of "optim_lsq" by default)
optim_lsq = optimoptions(‘lsqcurvefit’, ‘Algorithm’, ‘levenberg-marquardt’, ‘MaxFunctionEvaluations’,1000, ‘MaxIterations’, 1000, ‘FunctionTolerance’,10^-9, ‘StepTolerance’, 10^-9);
% optim_lsq = optimoptions(‘lsqcurvefit’, ‘Algorithm’, ‘trust-region-reflective’, ‘MaxFunctionEvaluations’,1000, ‘MaxIterations’, ‘FunctionTolerance’,10^-9, ‘StepTolerance’, 10^-9);
% optim_lsq = optimoptions(‘lsqcurvefit’, ‘Algorithm’, ‘interior-point’, ‘MaxFunctionEvaluations’,1000, ‘MaxIterations’, 1000, ‘FunctionTolerance’,10^-9, ‘StepTolerance’, 10^-9);

% Solver for lsqcurvefit
[p, residual, exitflag, output, jacobian] = lsqcurvefit(@EM_SS, p0, E_p, Abs, lb, ub);

%% Standard error calculation
ci = nlparci(p, residual, ‘Jacobian’, jacobian);
lowerbar = p – ci(:,1);
uppperbar = ci(:,2) – p;

if p == real(p)
disp(‘Real’)
else
disp(‘Complex with non-zero imaginary’)
end

if residual == real(residual)
disp(‘Real’)
else
disp(‘Complex with non-zero imaginary’)
end

if J == real(J)
disp(‘Real’)
else
disp(‘Complex with non-zero imaginary’)
end

%% Plot command
plot(E_p, Abs, ‘o’)
hold on
plot(E_p, EM_SS(p, E_p))
xlabel(‘Probe energy (eV)’)
ylabel(‘Absorbance.O.D’)
legend(‘Experimental Data’, ‘Fitted Curve’)
hold off

%% Parameter values (refer to command window)
p1 = p(1,1);
p2 = p(1,2);
p3 = p(1,3);
p4 = p(1,4);
p5 = p(1,5);
p6 = p(1,6);
X1 = [‘ A1 = ‘, num2str(p1)];
X2 = [‘ A2 = ‘, num2str(p2)];
X3 = [‘ Eg = ‘, num2str(p3)];
X4 = [‘ Eb = ‘, num2str(p4)];
X5 = [‘ R = ‘, num2str(p5)];
X6 = [‘ g = ‘, num2str(p6)];
disp(X1);
disp(X2);
disp(X3);
disp(X4);
disp(X5);
disp(X6);
Hi all, I am doing a fitting to my experimental data and I am now trying to calculate the confidence interval. However, it seems like there is something wrong with my code and the computer can’t really calculate it. May I ask where I am wrong? I tried following the instructions on this link but I still can’t get any results.clear; clc

load Steady_State_Data.mat % this contains the wavelength of light and absorbance of substrate and sample

%% Preamble

% Fundamental constants
h = 4.0135667696*10^-15; % units: eV/ Hz
c = 3*10^8; % SI units

% Data for fitting
E_p = E(n-N:167);
Abs = Absorbance(n-N:167) – min(Absorbance);
% Abs = Absorbance(n-N:167);

%% Curve fitting options

% Solver for lsqcurvefit
[p, residual, exitflag, output, jacobian] = lsqcurvefit(@EM_SS, p0, E_p, Abs, lb, ub);

%% Standard error calculation
ci = nlparci(p, residual, ‘Jacobian’, jacobian);
lowerbar = p – ci(:,1);
uppperbar = ci(:,2) – p;

if p == real(p)
disp(‘Real’)
else
disp(‘Complex with non-zero imaginary’)
end

if residual == real(residual)
disp(‘Real’)
else
disp(‘Complex with non-zero imaginary’)
end

if J == real(J)
disp(‘Real’)
else
disp(‘Complex with non-zero imaginary’)
end

%% Plot command
plot(E_p, Abs, ‘o’)
hold on
plot(E_p, EM_SS(p, E_p))
xlabel(‘Probe energy (eV)’)
ylabel(‘Absorbance.O.D’)
legend(‘Experimental Data’, ‘Fitted Curve’)
hold off

load Steady_State_Data.mat % this contains the wavelength of light and absorbance of substrate and sample

%% Preamble

% Fundamental constants
h = 4.0135667696*10^-15; % units: eV/ Hz
c = 3*10^8; % SI units

% Data for fitting
E_p = E(n-N:167);
Abs = Absorbance(n-N:167) – min(Absorbance);
% Abs = Absorbance(n-N:167);

%% Curve fitting options

% Solver for lsqcurvefit
[p, residual, exitflag, output, jacobian] = lsqcurvefit(@EM_SS, p0, E_p, Abs, lb, ub);

%% Standard error calculation
ci = nlparci(p, residual, ‘Jacobian’, jacobian);
lowerbar = p – ci(:,1);
uppperbar = ci(:,2) – p;

if p == real(p)
disp(‘Real’)
else
disp(‘Complex with non-zero imaginary’)
end

if residual == real(residual)
disp(‘Real’)
else
disp(‘Complex with non-zero imaginary’)
end

if J == real(J)
disp(‘Real’)
else
disp(‘Complex with non-zero imaginary’)
end

%% Plot command
plot(E_p, Abs, ‘o’)
hold on
plot(E_p, EM_SS(p, E_p))
xlabel(‘Probe energy (eV)’)
ylabel(‘Absorbance.O.D’)
legend(‘Experimental Data’, ‘Fitted Curve’)
hold off

User equipment in Small cell Network!

/ 2024-06-12 / Matlab

How to define a user equipment in a picocell or anykind of cell?How to define a user equipment in a picocell or anykind of cell? How to define a user equipment in a picocell or anykind of cell? small cells, user equipment MATLAB Answers — New Questions

plot some nodes from an .txt file

/ 2024-06-12 / Matlab

Hi! I would like to hope if there is an easy way to plot only the outermost nodes (the red nodes in the figure).
I am leaving the filename.txt file representing the nodes.Hi! I would like to hope if there is an easy way to plot only the outermost nodes (the red nodes in the figure).
I am leaving the filename.txt file representing the nodes. Hi! I would like to hope if there is an easy way to plot only the outermost nodes (the red nodes in the figure).
I am leaving the filename.txt file representing the nodes. nodes, plot, plotting, txt, text file, file MATLAB Answers — New Questions

Why/How is Circshift so fast?

/ 2024-06-12 / Matlab

I have the following function in Matlab:

function [RawDataKK]=DataCompressKKTest(Data,RXangle,s)

tSize=size(Data,1);
xSize=size(Data,2);
TXSize=size(Data,3);
RXSize=numel(RXangle);

RawDataKK=zeros(tSize,TXSize,RXSize);
DataTemp=zeros(tSize,xSize);

slope = s*sin(RXangle(:))/2;
nShift = round(slope.*((0:xSize-1) – (xSize-1)*(1-sign(RXangle(:)))/2));

for nR=1:RXSize
for nT=1:TXSize
for nx=1:xSize
DataTemp(:,nx)=circshift(Data(:,nx,nT),nShift(nR,nx));
end
RawDataKK(:,nT,nR)=sum(DataTemp,2);
end
end

end

I tried implementing it as a C++ function using the Eigen toolbox and the Matlab Data API for C++. The basic logic of the C++ implementation uses a reindexing approach to implement circshift.

“` lang-cpp
#include <iostream>
#include "mex.hpp"
#include "mexAdapter.hpp"
#include <Eigen/Dense>
#include <MatlabDataArray.hpp>
#include <cmath>
#include <math.h>
#include <omp.h>

class MexFunction : public matlab::mex::Function {
public:
// Factory to create MATLAB data arrays
matlab::data::ArrayFactory factory;

void operator()(matlab::mex::ArgumentList outputs, matlab::mex::ArgumentList inputs) {
checkArguments(outputs, inputs);

// Initialize input parameters
int tSize = inputs[0][0];
int xSize = inputs[0][1];
int TXSize = inputs[0][2];
int RXSize = inputs[0][3];
int RFlen = inputs[0][4];
auto ptr = getDataPtr<std::complex<double>>(inputs[1]);
Eigen::Map< const Eigen::MatrixXcd > Data( ptr, RFlen, xSize );
double s = inputs[2][0];

auto ptr2 = getDataPtr<double>(inputs[3]);
Eigen::Map< const Eigen::VectorXd > RXangle( ptr2, RXSize );

auto ptr3 = getDataPtr<int32_t>(inputs[4]);
Eigen::Map< const Eigen::MatrixXi > indices( ptr3, tSize, xSize*RXSize );

outputs[0] = factory.createArray<std::complex<double>>({static_cast<size_t>(tSize),static_cast<size_t>(TXSize*RXSize)});
auto ptrRecon = getOutDataPtr<std::complex<double>>(outputs[0]);
Eigen::Map<Eigen::MatrixXcd> RFDataKK(ptrRecon,tSize,TXSize*RXSize);

// Get num threads
int numThreads = omp_get_max_threads();
int nProc = omp_get_num_procs();
omp_set_num_threads(nProc*2);

#pragma omp parallel for
for (int nR = 0; nR < RXSize; nR++) {
Eigen::MatrixXcd shiftedData = Eigen::MatrixXcd::Zero(tSize*TXSize,xSize);
for (int nT = 0; nT < TXSize; nT++){
extractData(shiftedData(Eigen::seq(nT*tSize,(nT+1)*tSize-1),Eigen::all),
Data(Eigen::seq(nT*tSize,(nT+1)*tSize-1),Eigen::all),
indices(Eigen::all,Eigen::seq(nR*xSize, (nR+1)*xSize-1)), xSize, tSize);
}
RFDataKK(Eigen::all,Eigen::seq(nR*TXSize,(nR+1)*TXSize-1) ) = shiftedData.rowwise().sum().reshaped(tSize,TXSize);
}
}

void extractData(Eigen::Ref<Eigen::MatrixXcd> shiftedData, const Eigen::Ref<const Eigen::MatrixXcd>& Data,
const Eigen::Ref<const Eigen::MatrixXi>& indices, const long int& xSize, const long int& tSize) {
for (int i = 0; i < tSize*xSize; i++) {
int nt = i % tSize;
int nx = i / tSize;
int row = indices(nt,nx) % tSize;
int col = indices(nt,nx) / tSize;
shiftedData(row,col) = Data(nt,nx);
}
}
void checkArguments(matlab::mex::ArgumentList outputs, matlab::mex::ArgumentList inputs) {
std::shared_ptr<matlab::engine::MATLABEngine> matlabPtr = getEngine();
matlab::data::ArrayFactory factory;
// TODO: Implement remaining checks
}

template <typename T>
const T* getDataPtr(matlab::data::Array arr) {
const matlab::data::TypedArray<T> arr_t = arr;
matlab::data::TypedIterator<const T> it(arr_t.begin());
return it.operator->();
}

template <typename T>
T* getOutDataPtr(matlab::data::Array& arr) {
auto range = matlab::data::getWritableElements<T>(arr);
return range.begin().operator->();
}
};

“`

Where I precompute the values of indices using the following Matlab function:
function linIndices=DataCompressKKIndices(RXangle,s,tSize,xSize,TXSize,RXSize)

shiftedData = zeros(tSize, xSize, TXSize);
RFDatKK = zeros(tSize,TXSize,RXSize);
RFDataKK = zeros(tSize,xSize*RXSize);
slope=s*sin(RXangle(:))/2;

nShift = round(slope.*((0:xSize-1) – (xSize-1)*(1-sign(RXangle(:)))/2));

indices = mod((0:tSize-1).’ + reshape(nShift.’,[],1).’,tSize);
linIndices = indices + repmat((0:xSize-1)*tSize,1,RXSize);

end
When I perform a speed test in Matlab after compiling with the following parameters (with mingw GCC version 8.3), I find that I have not gained a meaningful speedup for the array sizes I am working with. OpenMP parallelization should at least give me an order of magnitude speed up (I have 24 threads on my machine). There are two questions that yields:
1. Why is a reindexing approach slower than doing circshift? A reindexing approach in Matlab (not shown here) is almost 2x slower than using nested for loops and circshift.
2. What exactly could circshift be doing under the hood that is so efficient? Is there some funky pointer arithmetic that could accomplish the functionality of circshift?

Compilation and testing code:
%% Compilation
mingwFlags = {‘CXXFLAGS="$CXXFLAGS -march=native -std=c++14 -fno-math-errno -ffast-math -fopenmp -DNDEBUG -w -Wno-error"’,…
‘LDFLAGS="$LDFLAGS -fopenmp"’,’CXXOPTIMFLAGS="-O3"’};
% ipath is the path to the eigen library.
tic; mex(ipath,mingwFlags{1},mingwFlags{2},mingwFlags{3},’CompressKK.cpp’); toc
tic; mex(ipath,mingwFlags{1},mingwFlags{2},mingwFlags{3},’CompressKKIndices.cpp’); toc

%% Initialize some random data
…
% tSize = 2688, xSize = 192, TXSize = 15, RXSize = 16 for trial cases

%% Timing Test
nTrials = 100;
T = zeros(nTrials,4);
for i = 1:nTrials

tic; indices = DataCompressKKIndices(p.RXangle,s,double(p.szRFframe+1),double(p.numEl),p.na,p.nRX);
RawDataKK3 = CompressKKIndices(param,cRF(1:param(5),p.ConnMap),s,p.RXangle,int32(indices));
RawDataKK3 = reshape(RawDataKK3,[p.szRFframe+1,p.na,p.nRX]); T(i,1) = toc;

tic; RawDataKK=DataCompressKKTest(Data,p.RXangle,s); T(i,2) = toc;
end
chkT = mean(T,1)
Timing Results:
chkT =

C++ version: 0.4867 0.8299I have the following function in Matlab: