Community Profile

# Alan Stevens

##### Last seen: Today
894 total contributions since 2020

View details...

Contributions in
View by

How can I randomize cube positions in matlab?
Like this? E=1; N=3; Nsamples=10; d=randi(N,1,Nsamples); s=randi(2,1,Nsample...

23 hours ago | 0

| accepted

how to I solve 2 eqns with 2 unknowns and plot 5 plots according to these solutions?
Here's a possible way. Only you will know if the results make sense deltaGrxn_std_rxn1 = -24800; %(J/mol) deltaHrxn_std_rxn1 ...

3 days ago | 0

Why do I get different results from the numerical solution and the analytical solution with ODE15S? The numerical solution looks smoother than the analytical one
% replace m_Soil = m_Soil_initial .* exp(- k1(i) .* t_measured(i+1)); % by m_Soil = m_Soil_initial .* exp(- k1(i) .* (t_mea...

4 days ago | 1

| accepted

Why do I get different results from the numerical solution and the analytical solution with ODE15S? The numerical solution looks smoother than the analytical one
Much easier to follow! Your "analytical" solution is incorrect for "constants" that change with time. See the following %% Re...

5 days ago | 0

must return a column vector
Do you want something like this sp=-0.5:0.5:14.5; for i = 1:length(sp) [t,y(:,i)]=ode45(@(t,y) phy_ode_1(t,y,sp(i)),0:0.5:1...

5 days ago | 1

Finding a range of data greater than 0.1
There must be a neater way, but the following might help: X = [ 0.02 0.17 0.32 0.28 0.04 -0.07 -0.01 -0.19 -0.45 ....

5 days ago | 0

| accepted

How to use ode45 with a time dependant second order differential equation
Turn your second order equation into two simultaneous first order equations.

6 days ago | 0

how can i solve this problem with rk4 method?
If m=20, k=20, c=40 then function f should be f = -(c/m)*v - k/m f=@(t,x,v) -2*v -x; %dvdt

7 days ago | 0

| accepted

How to solve a function with different ranges
Try C_ox = [16;15;7.5;2;7.5;15;15]; C_ox(C_ox<=15)=C_ox(C_ox<=15)/15; C_ox(C_ox>15)=1

8 days ago | 0

how can i solve second order ODE with RK-4 without using a built in function in matlab?
This K11 = RK4(t(i), y1(:, i)); should be | K11 = RK4(t(i), y(:, i)); and this f12 = -3*y(1)+30*t+10; ...

9 days ago | 0

| accepted

How to design the membership function in matlab?
How about the following for rule 3 (I'll leave you to invert for rule 4). x = [-180 -90 -89.001 89.001 90 180]; y = (x+180)/90...

12 days ago | 0

| accepted

Help for plotting graph. Can someone help me?
In your while loop you don't update either nErrorsBitsW or nErrorsBitsInf so they always stay at 0, and never reach minNbits.

12 days ago | 0

how I can insert these specific colours into my figures
Do you mean something like this? newcolors = [0 0.4470 0.7410; 0.8500 0.3250 0.0980; 0.9290 0.6940 0.1250...

14 days ago | 1

Transpose x from a row vector to a column vector using the transpose operator. The program is prompting the x does not have correct values. the code i have entered is below
You probably meant x = [1:5]; % ie the ; is after the ] However, it seems to work ok for me as you wrote it!

14 days ago | 0

Replace a entry of a table of Bisection Method for a specific term
Try using NaN or [ ];

14 days ago | 0

| accepted

Plotting the intersection of a composition function
Do you mean something like this? Sfn = @(x) (x+1/4).*(x<=1/2) + (x+3/4).*(x>1/2); x = linspace(0,1,100); n=10; S = zeros(n,n...

24 days ago | 0

Sun Synchronous with For Loop
When I run the program you've listed above it produces the graph you show!

24 days ago | 0

| accepted

Integration of a function with variable parameter
Do you mean something like this? H = @(tau, lam, tt) lam./exp(tt-tau); T=50; step=1000; h=T/step; t=0:h:T; lambda = rand(1...

25 days ago | 0

| accepted

How to get sinusodial behaviour from 2nd order ode using function handle?
You coud try implementing the function along these lines (obviously, you will need to use your own values for alpha etc): alpha...

26 days ago | 0

How to find absolute maximum value of (x*(x-.25)*(x-.5)*(x-1))
You could just do something like gx = @(x) ((x.^4) -(1.75*x.^3)+(0.875*x.^2)-(0.125*x)); X = roots([4, -5.25, 1.75, -0.125]); ...

28 days ago | 0

I want to see N,M first and then K,M in the same legend. I can see only N,M like the attached picture.
Do you mean like this? N = [10 20 30 40 50]; M = [1 2 3 4 5]; K=[1 3 5 6 7]; x = linspace(0, 1, 17); legendString = "N = " ...

28 days ago | 0

| accepted

How to take integral with for loop?
Add the command I = sum(final); after the loop.

29 days ago | 0

| accepted

Solving queue problem iterating through array
Try Lock19(Lock19~=-5)=0; Lock19(Lock19==-5)=3;

29 days ago | 0

Sum of even numbers
Like so s = test(6); disp(s) function s = test(n) if n <= 0 %for n<= 0 the result would be 0 s = 0; els...

1 month ago | 0

Stopping ode45 when encountering errors and retrieving results
The following makes your example work. However, I suspect your real problem is more complicated. If so, you should upload it. ...

1 month ago | 0

After comma precision tracking for if statement
Here's one possibility a=85.0093792283283; b=85.0093791964294; a = floor(a*10^3); b = floor(b*10^3); if a==b disp('n...

1 month ago | 0

help me solve this if statement
Remove the ] in the top line! Then number = randi([0,9]) evens = [2,4,6,8]; odds = [1,3,5,7,9]; if ismember(number,evens) ...

1 month ago | 0

𝑦 = 2𝑐𝑜𝑠3𝑥
help plot

1 month ago | 0