Alan Stevens
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891 total contributions since 2020
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Answered
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...
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...
1 día ago | 1
| accepted
Answered
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...
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...
2 días ago | 0
Answered
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...
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...
2 días ago | 1
Answered
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 ....
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 ....
2 días ago | 0
| accepted
Answered
How to use ode45 with a time dependant second order differential equation
Turn your second order equation into two simultaneous first order equations.
How to use ode45 with a time dependant second order differential equation
Turn your second order equation into two simultaneous first order equations.
3 días ago | 0
Answered
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
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
4 días ago | 0
| accepted
Answered
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
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
5 días ago | 0
Answered
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; ...
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; ...
6 días ago | 0
| accepted
Answered
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...
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...
9 días ago | 0
| accepted
Answered
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.
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.
9 días ago | 0
Answered
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...
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...
11 días ago | 1
Answered
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!
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!
11 días ago | 0
Answered
Replace a entry of a table of Bisection Method for a specific term
Try using NaN or [ ];
Replace a entry of a table of Bisection Method for a specific term
Try using NaN or [ ];
11 días ago | 0
| accepted
Answered
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...
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...
21 días ago | 0
Answered
Sun Synchronous with For Loop
When I run the program you've listed above it produces the graph you show!
Sun Synchronous with For Loop
When I run the program you've listed above it produces the graph you show!
21 días ago | 0
| accepted
Answered
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...
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...
22 días ago | 0
| accepted
Answered
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...
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...
23 días ago | 0
Answered
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]); ...
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]); ...
25 días ago | 0
Answered
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 = " ...
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 = " ...
25 días ago | 0
| accepted
Answered
How to take integral with for loop?
Add the command I = sum(final); after the loop.
How to take integral with for loop?
Add the command I = sum(final); after the loop.
26 días ago | 0
| accepted
Answered
Solving queue problem iterating through array
Try Lock19(Lock19~=-5)=0; Lock19(Lock19==-5)=3;
Solving queue problem iterating through array
Try Lock19(Lock19~=-5)=0; Lock19(Lock19==-5)=3;
26 días ago | 0
Answered
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...
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...
alrededor de 1 mes ago | 0
Answered
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. ...
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. ...
alrededor de 1 mes ago | 0
Answered
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...
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...
alrededor de 1 mes ago | 0
Answered
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) ...
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) ...
alrededor de 1 mes ago | 0
Answered
Error: ode45 Must return a column vector?
Like this? % the total time domain response % System parameters k3 = 15; k1 = 10.0; k2 = 10.0; m1 = 2.0; m2 = 6.0; L = 1.0;...
Error: ode45 Must return a column vector?
Like this? % the total time domain response % System parameters k3 = 15; k1 = 10.0; k2 = 10.0; m1 = 2.0; m2 = 6.0; L = 1.0;...
alrededor de 1 mes ago | 1
| accepted
Answered
How to solve following BVP ODE?
Weird ODE and initial boundary condition! You can solve for small values of x using the following (where y(x=0) was chosen by t...
How to solve following BVP ODE?
Weird ODE and initial boundary condition! You can solve for small values of x using the following (where y(x=0) was chosen by t...
alrededor de 1 mes ago | 1
| accepted
Answered
Array indexes must be positive integers or logical values.
Looks like you are using SUM when you want sum. Change to: SUM= E1*sum(V(3:IOUT+1,JOUT+2)).... Also, in line 59, you should h...
Array indexes must be positive integers or logical values.
Looks like you are using SUM when you want sum. Change to: SUM= E1*sum(V(3:IOUT+1,JOUT+2)).... Also, in line 59, you should h...
alrededor de 1 mes ago | 1
| accepted
Answered
How to get real solutions of a "system of nonlinear equations"?
If you are willing to do the differentiation by hand then the following works % L = 2*x^2 -2*x*y+y^3 + lambda*(x^2 + y^2 -4); ...
How to get real solutions of a "system of nonlinear equations"?
If you are willing to do the differentiation by hand then the following works % L = 2*x^2 -2*x*y+y^3 + lambda*(x^2 + y^2 -4); ...
alrededor de 1 mes ago | 0
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