Unexpected MATLAB operator.( error)

clear all

K=10;

well=-1000;

iw=16; 

jw=6;

eps=0.0001;

nx= 50; 

ny=10;

H=1000;

w=1.7; 

u=ones(nx+1,ny+1)*100; 

h=H/ny; 

maxit=400; 

tol=eps*h*h;

for m =1 : maxit  

      numi=0;   

      j= 1;   

      for i = 2 :nx 

          utemp= (( 2*u(i,j+1) + u(i+1,j) + u(i-1,j))*0.25);  

          utemp= (1-w)*u(i,j) + w*utemp;   

          error= abs(utemp - u(i,j)); 

          u(i,j)=utemp;   

          if (error < tol) 

              numi=numi +1;  

          end

      end

      for j = 2 : ny  

          for i = 2 : nx 

              utemp= (( u(i,j-1) + u(i-1,j) + u(i+1,j) + u(i,j+1))*0.25);

                            if ((i==iw) & (j==jw)) 

                                utemp= (( u(i,j-1) + u(i-1,j) + u(i+1,j) + u(i,j+1) + well/K)*0.25);

                            end

                            utemp= (1-w)*u(i,j) + w*utemp;

                            error= abs(utemp - u(i,j));  

                            u(i,j)=utemp; 

                            if (error < tol) 

                                numi=numi +1;   

                            end

          end

      end

      j= ny + 1; 

      for i = 2 : nx  

          utemp= (( 2*u(i,j-1) + u(i+1,j) + u(i-1,j))/4);  

          utemp= (1-w)*u(i,j) + w*utemp;  

          error= abs(utemp - u(i,j));  

          u(i,j)=utemp; 

          if (error < tol)

              numi=numi +1;  

          end

      end

      if (numi == (nx-1)*(ny+1)) break; end 

end

>darcy2d

>m  

        27  

> numi  

      539

   surf(u)

contour(u)

----------------------------------------------------------------

After execution in matlab:

??? Error: File: darcy1.m Line: 53 Column: 1

Unexpected MATLAB operator.

LINE 53:  >darcy2d

Answer 1

[Jonathan Sullivan]

Does your code actually have those carrots in there?

>darcy2d

If so, remove the carrots and your problem will be solved

darcy2d

Answer 2

[Walter Roberson]

The part from

>darcy2d

onward is an illustration of how to use the file. From there on should not be saved in the file. Everything before that should be saved into a file named darcy2d.m . Then to use it, at the command line invoke

darcy2d
surf(u)
contour(u)

Those commands should not be saved as part of the .m file.