Plotting of null surfaces and Warning: Matrix is singular to working precision.

2 views (last 30 days)
Problem: I have the following three sets of equation which i need to plot as planes in 3D system.
I ,N and T are there variables representing the null surfaces .Now i don't have to solve them, instead i just have to plot them as planes and see their intersections. Here is the plot i am supposed to get,
graph.png
My attempt: I tried to use meshgrid and surf to plot the plane but i don't understand how to proceed with the first two. The third one i tried like
[T N] = meshgrid(0:0.01:5);
I= (0.33*(0.3+T))/((T+0.2)*(0.3+T)-0.01*T);
surf(T,N,I);
This led me to a warning: Matrix is singular to working precision. I checked if somewhere the denominator vanishes but they don't.
For the second i tried:
[I N] = meshgrid(0:0.01:5);
T= 1-I/3-N/1.5;
surf(I,N,T);
But again this did give something but nothing like the above figure. I could be completly wrong with my attempt here, hence any guidance or a small code will be extremely helpful. The variable I, T, and N are Immune, Tumor and Normal in the above figure.
Thank you.
  3 Comments
Vira Roy
Vira Roy on 22 Dec 2019
Thanks David for the reply. Earlier one member had commented the similar solution as your but seems he deleted his reply.
Though your problem does solve the issue, I was having problem plotting the other equations as a plane in the same plot. Like the second equation along with the code you gave.
Mu problem is do i have to use two different meshgrid to plot the other equations or i can use the same meshgrid.
Let me show what i did.
[T N] = meshgrid(0:0.05:3.5);
I1= (0.33*(0.3+T))./((T+0.2).*(0.3+T)-0.01*T); %the code you suggested
I2= 3-2.*N-3.*T; %this is the second equation with I in LHS
surf(T,N,I1, 'EdgeColor','none');
hold on
surf(T,N,I2, 'EdgeColor','none');
view(30,30)
This doesn't work and hence my problem, how should i proceed to plot all of them in the same graph. Any help or guidance would be helpful.
Thank you.
David Goodmanson
David Goodmanson on 22 Dec 2019
Hi Vira,
I don't believe the second and third equations correspond to the figure in your question. For the third equation, if you plug in T = 0 you get 1.5 for any N, but the figure shows 5. For the second equation, if you plug in N=0 T=0 you get 3, but the figure (up from the back corner where you can't actually see the origin T=0,N=0) shows 9.

Sign in to comment.

Answers (0)

Products


Release

R2016a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!