Community Profile

photo

Alan Stevens


Last seen: Today
645 total contributions since 2020

Alan Stevens's Badges

  • Guiding Light
  • 6 Month Streak
  • Knowledgeable Level 4
  • First Answer

View details...

Contributions in
View by

Answered
How to create a new variable in each iteration of the for loop?
One way as follows: y = 1024; %for example winSize=[16,64,256,1024,4096]; for i = 1:numel(winSize) if winSize(i) == 16 ...

18 hours ago | 0

| accepted

Answered
Non-Linear Coupled First-Order ODEs (with multiple derivative terms in each equation).
These ode's can be rearranged as follows: As long as you know initial values for a, b and c, then given that you know everyth...

1 day ago | 0

| accepted

Answered
How can i make the integral curves?
Like so? [x,y] = meshgrid(1:0.5:6,-3:0.5:2); u = ones(size(x)); v = (x.*y+y.^3)/2*x.^2; r = sqrt(u.^2 + v.^2); plot([0,0],[...

3 days ago | 0

| accepted

Answered
Convert one matrix to two matrices with the order of the initial matrix
Try r1 = r; r1(:,2:2:end) = 0; r2 = r; r2(:,1:2:end) = 0;

3 days ago | 1

| accepted

Answered
How to clump/consolidate values together using the mean function
Here's one way cw = 4; %cell width a = 1:8; b = (1:8)'; c = a.*b; mat=ones(8,8); %temporary matrix avfn = @(m) mean(m,'A...

3 days ago | 0

Answered
solve non linear equations
Add these lines at the end to get the values of S and J Soln = vpasolve([eqn1, eqn2],[S, J],[1 1]); disp(Soln.S) disp(Soln.J)...

3 days ago | 0

Answered
How to find an unknown in an integral equation
Here's one way: nA0 = 1; % Initial guess nA = fzero(@fn, nA0); disp(nA) function Z = fn(nA) alphaA = 0.52; T ...

4 days ago | 0

| accepted

Answered
Error: Function definition not supported in this context. Create functions in code file.
You need to turn Z=sin(2*pi*fc*p)./(pi*p); %Define truncated Sinc function% into Z=sin(2*pi*fc*p)./(pi*p); %Define trunca...

4 days ago | 1

Answered
Using a another function within ODE45
More like this (but note the comments near the end): %Default Values m_c = 2; % Container Mass s1 = 16; ...

4 days ago | 1

| accepted

Answered
Conditionals within ODE45
You could try the following simplistic approach %Default Values m_c = 2; % Container Mass s1 = 16; % Sp...

4 days ago | 1

| accepted

Answered
Need Help..............Error using stem (line 43) X must be same length as Y.
Either you want stem(t,xaa); or you want to use t1 in the definitions of xa11, xa22 etc.

5 days ago | 1

Answered
What am I doing wrong here I keep getting a plot with either to many things on it or not enough all I want is a plot with two y axis and an x axis
Like this g = 9.81; theta = 46.97; theta2= 55; v1= 13.5; v2= 16.05; x= (0:0.1:2.3); x2= (0:0.1:5.14); y= x*tan(the...

5 days ago | 0

| accepted

Answered
Two linear equation with absolute value equation
Do you mean something like this X0 = [-50 -5]; [X, Fval] = fminsearch(@(X) fn(X),X0); x2 = X(1); x1 = 50-x2; x4 = X(2); x3 =...

5 days ago | 1

Answered
10%+10%
Because the % symbol indicates that the rest of the line is a comment. So the only non comment parameter Matlab sees is the fir...

5 days ago | 1

| accepted

Answered
Function handling problem in loop
Try doc str2num to convert from text to numeric. Also, you might find it easier to define: k = [5.16 5.12 4.89 4.79 4.99 5.4...

5 days ago | 0

| accepted

Answered
I can't randomly distribute the dots
Try using Yikikz=rand(size(Elevation)).*Elevation;

5 days ago | 1

Answered
How to fix error in fsolve
Is it just a case of changing F(1) = X(1) - exp(13.5-(2700/(x(3)-55))); to F(1) = x(1) - exp(13.5-(2700/(x(3)-55)));

6 days ago | 1

Answered
Error in using Integration, How to fix it ?
Since x has t in the denominator. t=0 will cause problems, so start at t = 0.02 instead, perhaps! This would require a change i...

6 days ago | 0

| accepted

Answered
Ode and monod solver
Your equation has the following analytic solution (assuming Xa is a constant): You can plug in the known values for S0 (ie. t...

6 days ago | 1

| accepted

Answered
How to plot a large data set with markers to differentiate two overlapping lines?
How about plotting every n points. For example plot(t(1:1000:end),n_d(1:1000:end),'o') hold on plot(t(500:1000:end),n_r(500:...

8 days ago | 0

| accepted

Answered
there is also a mistake here i can't recognize it , please help
You need N = [-V3*cos(th3(ii))-40*W2(ii).^2*cos(th2(ii))+C(ii)*W3(ii).^2*cos(th3(ii))+V3*W3(ii)*sin(th3(ii)); V3*sin(t...

8 days ago | 0

Answered
How to vectorize this function?
You need a ./ (i.e. dot /) x3=@(phi) (R-((3-2.*sin(phi))./(1-0.5.*sin(phi)).*R)/4).*cos(phi) ...

8 days ago | 0

Answered
Plotting graph with Alpha and spectral radius
It works if you set i = 0.1:0.1:10. With i = 0; the inverse of S is full of Inf's.

8 days ago | 0

| accepted

Answered
Conditional with time in ode45
Include upsilon within the odefcn mu = 6.25e10^-3; eta = 6.25e10^-3; beta = 0.03813350836; gamma = 0.01165323939; delta = 1...

8 days ago | 0

| accepted

Answered
what's wrong with this code. why it show error can anyone tell?
You probably want something like this (don't enclose it with the statement 'function matlab' - that won't work). Remember to in...

8 days ago | 0

Answered
Plot with 2 parameters
Do you mean something like this: theta = -90:90; ri = 0.5; ro = 1.5; x = [ri*cosd(theta) ro*cosd(-theta) 0]; y = [ri*sind(th...

9 days ago | 1

Answered
Please, how can I solve runKut4 in line 6?
Try t = 0.0; tStop = 6.0; y = [1.5 0]; h = 0.1; [T,Y] = ode45(@dEqs,[0 tStop],y); plot(T,Y(:,1),'ko-') xlabel('time (s)')...

10 days ago | 0

| accepted

Answered
ode45 function matrix dimensions problem
You need to loop through the Y_H values. See below global mu_H Ks X_BH teta Ss_in mu_Hmax=0.15; %days^-1 T=22.6; %centigrad...

10 days ago | 0

Answered
I am getting this error "Assignment has more non-singleton rhs dimensions than non-singleton subscripts". Please help. Mw, Cw and Kw are 243X243 matrices.
It gets past your indicated Error line for me, but fails because you haven't defined Mw, Cw or Kw.

10 days ago | 0

Answered
Error: Unable to perform assignment because the left and right sides have a different number of elements.
There are a lot of missing indices and definitions. In the following the indices are repaired; however, you will need to define ...

10 days ago | 0

| accepted

Load more