Polat plot with colors depending on values.

Question

Danila Zharenkov 2014-2-16

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/116356-polat-plot-with-colors-depending-on-values

回答： Danila Zharenkov 2014-3-11

Hello,

I'm solving PDE system numerically, as a result I've got the matrix sized (size(r), size(theta)) with values of function in different polar coords (radius, angle). I need to plot the surface like on this picture

The color of point must depend on value from result matrix.

Is there any built-in solution for this task? Here is the main part of my code, if it helps.

    for t=1:nt-1
    for i=2:nr-1
        for j=2:nth-1
            %derivatives
            d2udr2= (u(i+1,j,t)-2*u(i,j,t)+u(i-1,j,t))/hr^2;
            d2udth2= (u(i,j+1,t)-2*u(i,j,t)+u(i,j-1,t))/hr^2;
            dudr=(u(i+1,j,t)-u(i-1,j,t))/(2*hr);
            d2vdr2= (v(i+1,j,t)-2*v(i,j,t)+v(i-1,j,t))/hr^2;
            dvdr=(v(i+1,j,t)-v(i-1,j,t))/(2*hr);
            d2vdth2= (v(i,j+1,t)-2*v(i,j,t)+v(i,j-1,t))/hr^2;
            %centre nodes
            u(i,j,t+1)=u(i,j,t)+ht*(psi*(d2udr2+(1/r(i))*dudr+d2udth2)+u(i,j,t)*(1-k*v(i,j,t)));%u(i,j,t)*(1-ro*b*v(i,j,t))*(1-b*v(i,j,t)-u(i,j,t))); %u(i,j,t)*(1-u(i,j,t)-c*v(i,j,t)));
            v(i,j,t+1)=v(i,j,t)+ht*(mu*(d2vdr2+(1/r(i))*dvdr+d2vdth2)+a*v(i,j,t)*(1-x*u(i,j,t)));%a*v(i,j,t)*(1-q*u(i,j,t))*(1-u(i,j,t)-b*v(i,j,t)));%a*v(i,j,t)*(1-c*u(i,j,t)-b*v(i,j,t)));
        end
    end
    %boundaries for r
    for j=1:nth
        u(1,j,t+1)=u(3,j,t+1);
        u(nr,j,t+1)=u(nr-2,j,t+1);
        v(1,j,t+1)=v(3,j,t+1);
        v(nr,j,t+1)=v(nr-2,j,t+1);
    end
        u(:,1,t+1)=u(:,nth-1,t+1);
        v(:,1,t+1)=v(:,nth-1,t+1);
        u(:,nth,t+1)=u(:,2,t+1);
        v(:,nth,t+1)=v(:,2,t+1);
%         %corners
        u(1,1,t+1)=u(1,2,t+1);
        u(1,nth,t+1)=u(1,nth-1,t+1);
        u(nr,1,t+1)=u(nr-1,1,t+1);
        u(nr,nth,t+1)=u(nr-1,nth,t+1);
        v(1,1,t+1)=v(1,2,t+1);
        v(1,nth,t+1)=v(1,nth-1,t+1);
        v(nr,1,t+1)=v(nr-1,1,t+1);
        v(nr,nth,t+1)=v(nr-1,nth,t+1);
  end