# Wan Ji

### Wuhan University

Last seen: 1 day ago Active since 2021

Followers: 0   Following: 0

Research Interest: computational mechanics and modeling the world

Programming Languages:
Python, C++, C, MATLAB, Fortran
Spoken Languages:
English, French, Chinese

All

#### Feeds

View by

How to show node/element numbers on the boundary ONLY?
Hi, friend, Here are some tips for you. Firstly, you can find those edges (an edge is generally denoted by two nodes) that are...

3 years ago | 0

Call a folder from desktop and use images inside it
Hey, friend, Using uigetfile is a nice choice, for example [file,path,indx] = uigetfile( ... {'*.jpg;*.png;*.tiff;*.tif;*.bmp...

3 years ago | 0

| accepted

Question

Matlab default font monospace is not a wise choice
Did anyone encounter a problem when writing an m-script on matlab? The problem is that your naked eyes can't tell the number '1'...

3 years ago | 1 answer | 0

### 1

How can I fix my function?
Hey， friend Just try the inline function ispythag = @(a,b,c)a.^2+b.^2 == c.^2; a = ispythag(1,2,3) b = ispythag(3,4,5) Then...

3 years ago | 0

| accepted

Matlab versions supported on Windows 11?
WINDOWS 11 itself should support running the softwares on win10. ELSE microsoft would not release it and clients would not use i...

3 years ago | 0

Using ODE45 for first order diff equation with three different variables
For example function dxdt = func(t,x,g) dxdt = zeros(3,1); dxdt(1) = (0.1*x(1))+(0.25*x(2))-(g*x(3)); dxdt(2) = (0.1*x(1))+(...

3 years ago | 2

| accepted

how to write to solve this type of system of equations ?
Hey friend Just expand the left items of the two equations, extract u'' and v'', then an ode45 solver is there for you.

3 years ago | 0

multiple graphs in one script
Modified the code as %% 6 x = ([-2*pi:0.1:2*pi]); f = x-sin(x) g = 1-x.*cos(x) figure(1);clf; plot(x,f,x,g) title('f(x) &...

3 years ago | 0

How to check if an array is empty without using any built in functions
Use isempty x = []; isempty(x) Then the answer is ans = logical 1

3 years ago | 1

| accepted

I want to co-relate the local coordinate system with global co-ordinate system of a 8-noded element. How to do it in matlab?
You need to add the element information element_id = 5; % for example, the local element id is 5 selected_element = element(el...

3 years ago | 0

| accepted

Question

I don't know how to avoid eval
Hi friends from community, I am very confused on how to manage 'eval' function existing in my code, i need it to be removed fro...

3 years ago | 3 answers | 0

### 3

Total Solution Differential Equation
If u(t) = 1, then your solution is right. If it is a function with respect to time, then your solution is wrong. Exact code: ...

3 years ago | 0

How to plot such figure in MATLAB?
use polarplot theta = 0:0.1:pi; r = 1+0.6*sin(10*theta); polarplot(theta,r); set(gca,'ThetaLim',[0 180]) set(gca,'Rdir','re...

3 years ago | 1

| accepted

How to plot a 3D vortex flow
If you donot have a mesh, then you need to reconstruct your mesh! X = X(:); Y = Y(:); Z = Z(:); U = U(:); V= V(:); W=W(:); min...

3 years ago | 0

| accepted

Saving the regression trained model
You should save the trained model after click the 'export' the model to workspace. (you can see you saved model in workspace) ...

3 years ago | 0

| accepted

Solving 3 simultaneous equations using solve.
Do not use 'pi' use pi instead %define attributes: gamma=21.05; phi=35.55; phi1=0.75*phi; d=0.6; syms L Rs Rb; zc=(0.3*ph...

3 years ago | 0

How to add consecutive numbers from a column in a .txt file?
Just use movsum a = [1 1 8 2 3 1]; b = movsum(a,2); % I should apologize for not adding 2 b = b(2:end) The answer b = ...

3 years ago | 1

| accepted

How do i write the function for the taylor polynomial of cos(x) using for loops and no anonymous function
If a large x is selected, then use function Pn = taylor_cos(a,n) x=mod(abs(a),2*pi); % if(x>=pi) x = 2*pi-x; end Pn=1;...

3 years ago | 0

| accepted

How to use sym and function handle(@) in same code
Hi, use matlabFunction, my friend syms theta Ai = cos(theta).*[1 1 2; 4 5 6; 9 1 3] Bi = tan(theta).*[6 9 1; ...

3 years ago | 0

| accepted

How to average first two dimension of 3D array/matrix?
Just use mean function to average first two dimension of 3D matrix a = rand(2,3,4); % I just use rand function so the result is...

3 years ago | 1

Save points or data in right order
I have answered this question before, now I have a better solution to this problem which can identify many connected regions cl...

3 years ago | 0

| accepted

How to make a={'1','2','3','4'} to b={'1234'}
The simple way is a={'1','2','3','4'}; b = {[a{:}]} Answer b = 1×1 cell array {'1234'}

3 years ago | 0

| accepted

how do you sum using loop?
x=1:100; f=@(x)x.*(1+x); S=sum(f(x));%this should be ok %or use loop f=@(x)x.*(1+x); S=0; for i=1:100 S=S+f(i); end...

3 years ago | 0

How to form a sphere with 1's in a 3D matrix
If there is no scale factor effect with different directions: m = 80; n = 100; p=90; [px,py,pz] = meshgrid(1:n, 1:m, 1:p); ra...

3 years ago | 1

| accepted

How to sum the values when they are bigger than 25, 50, 75, (conditional) and they are from the same group?
That's quite simple, you don't need to compare them clc;clear ID = ['1_A' ; '1_A'; '1_A'; '2_B'; '2_B'; '3_C'; '3_C';...

3 years ago | 0

| accepted

How to i change the SNR to Vector?
SNR = -20:10:30; a(numel(SNR)) = helperModClassTestChannel(); for i = 1:1:SNR a(i).SNR = SNR(i); end

3 years ago | 0

Why is it not taking the sqrt function, and how to fix it?
You should transform char format to double then do your work B = str2num(B); H = str2num(H); n = str2num(n); s = str2num(s);...

3 years ago | 0

plot the equation graph
Hi, It is not neccessary to solve this equation x = 0:0.00001:1; f = @(x,m,a)(m*pi+atan((x)/(1-x))+atan((a+x)/(1-x)))./sqrt(1...

3 years ago | 0