MATLAB: How to plot 3-d using surf(xyu) where -1

Question

PROGRAM Jacobi_method
IMPLICIT NONE
! Declare Variables
Real, allocatable :: x(:),y(:),u(:,:), v(:,:),u_old(:,:)
Real:: xy,h,Smax,tolerence,error
Integer:: i,j,JI
Print *, 'Enter the space size:'
read*, xy
Print*, 'Enter the final space:'
read*, Smax
h=Smax/xy !The size of spacestep
Print*, 'This gives stepsize of space h=',h
error = 1.d0
tolerence = 10E-4
JI = 20   ! Total number of space stepsize
allocate (x(0:JI),y(0:JI),u(0:JI+1,0:JI+1),v(0:JI+1,0:JI+1),u_old(0:JI+1,0:JI+1))
open(10,file='Jacobi_method.m')
!Initial Conditions
x(0)= -1.0
x(JI)= 1.0
y(0)= -1.0
y(JI)= 1.0
do i=0,JI
do j=0,JI
x(i)=  -1 + i*h   ! x-axix
y(j)=  -1 + j*h   ! y-axis
u(i,j)= 0         ! Entire Boundary is zero
end do
end do
while (error .GT. tolerence) do  ! To stop
  do i=1, JI-1
    do j=1,JI-1
u_old(i,j)= u(i,j)  ! To store the old values
!Using 5-point scheme Formulae and rearranging the equation
v(i,j)= 0.25*(u(i+1,j)+u(i,j+1)+u(i-1,j)+u(i,j-1)+h**2) 
      end do
     end do
      do i=1, JI-1
       do j=1, JI-1
  u(i,j)= v(i,j)  ! Giving the new values
          end do
        end do
error =0.d0        ! Now, error reading the value of zero
     do i=1,JI-1
       do j=1, JI-1
error = error + abs(u(i,j)- u_old(i,j))  ! To Stop
        end do
         end do
        end do
!Print out the Approximate solution in matlab to get output and plot 
write(10,*)  'xyu =['                           
     do i=0, JI
       do j=0,JI
write(10,*) y(j),x(i),u(i,j)
 end do
 end do
write(10,*) ']'
write(10,*) "  surf(xyu)"                      !Ploting diagram x,y,u
write(10,*) "xlabel('x'),ylabel('y'),legend('Approximate Jacobi Scheme')"
close(10) 
END PROGRAM Jacobi_method

Note: This is fortran code to generate output and plot the graphs in the matlab. There are no errors in fortran code and i can generate the outputs of u(i,j) between but -1<x<1 and -1<y<1 . I want to plot the graph of u(i,j) between -1<x<1 and -1<y<1 in the matlab but the plots is not properly working between -1 to 1 in both x-axis and y-axis.

To answer my question: you can look out the code after this (!Print out the Approximate solution in matlab to get output and plot) which is code for the matlab.

To make it clear, here is the output i want to plot generate by fortran code into matlab:

xyu =[  x-axis        y-axis           u(i,j)
     -1.00000        -1.00000         0.00000
    -0.900000        -1.00000         0.00000
    -0.800000        -1.00000         0.00000
    -0.700000        -1.00000         0.00000
    -0.600000        -1.00000         0.00000
    -0.500000        -1.00000         0.00000
    -0.400000        -1.00000         0.00000
    -0.300000        -1.00000         0.00000
    -0.200000        -1.00000         0.00000
    -9.999999E-02    -1.00000         0.00000
     1.490116E-08    -1.00000         0.00000
     0.100000        -1.00000         0.00000
     0.200000        -1.00000         0.00000
     0.300000        -1.00000         0.00000
     0.400000        -1.00000         0.00000
     0.500000        -1.00000         0.00000
     0.600000        -1.00000         0.00000
     0.700000        -1.00000         0.00000
     0.800000        -1.00000         0.00000
     0.900000        -1.00000         0.00000
      1.00000        -1.00000         0.00000
     -1.00000       -0.900000         0.00000
    -0.900000       -0.900000        1.723304E-02
    -0.800000       -0.900000        2.946638E-02
    -0.700000       -0.900000        3.867569E-02
    -0.600000       -0.900000        4.578741E-02
    -0.500000       -0.900000        5.130390E-02
    -0.400000       -0.900000        5.552766E-02
    -0.300000       -0.900000        5.865262E-02
    -0.200000       -0.900000        6.080576E-02
    -9.999999E-02   -0.900000        6.206776E-02
     1.490116E-08   -0.900000        6.248359E-02
     0.100000       -0.900000        6.206776E-02
     0.200000       -0.900000        6.080576E-02
     0.300000       -0.900000        5.865262E-02
     0.400000       -0.900000        5.552766E-02
     0.500000       -0.900000        5.130390E-02
     0.600000       -0.900000        4.578741E-02
     0.700000       -0.900000        3.867569E-02
     0.800000       -0.900000        2.946638E-02
     0.900000       -0.900000        1.723304E-02
      1.00000       -0.900000         0.00000
     -1.00000       -0.800000         0.00000
    -0.900000       -0.800000        2.946638E-02
    -0.800000       -0.800000        5.195795E-02
    -0.700000       -0.800000        6.945068E-02
    -0.600000       -0.800000        8.317228E-02
    -0.500000       -0.800000        9.390321E-02
    -0.400000       -0.800000        0.102157
    -0.300000       -0.800000        0.108280
    -0.200000       -0.800000        0.112506
    -9.999999E-02   -0.800000        0.114985
     1.490116E-08   -0.800000        0.115803
     0.100000       -0.800000        0.114985
     0.200000       -0.800000        0.112506
     0.300000       -0.800000        0.108280
     0.400000       -0.800000        0.102157
     0.500000       -0.800000        9.390321E-02
     0.600000       -0.800000        8.317228E-02
     0.700000       -0.800000        6.945068E-02
     0.800000       -0.800000        5.195795E-02
     0.900000       -0.800000        2.946638E-02
      1.00000       -0.800000         0.00000
     -1.00000       -0.700000         0.00000
    -0.900000       -0.700000        3.867569E-02
    -0.800000       -0.700000        6.945068E-02
    -0.700000       -0.700000        9.400019E-02
    -0.600000       -0.700000        0.113552
    -0.500000       -0.700000        0.128985
    -0.400000       -0.700000        0.140923
    -0.300000       -0.700000        0.149812
    -0.200000       -0.700000        0.155961
    -9.999999E-02   -0.700000        0.159572
     1.490116E-08   -0.700000        0.160764
     0.100000       -0.700000        0.159572
     0.200000       -0.700000        0.155961
     0.300000       -0.700000        0.149812
     0.400000       -0.700000        0.140923
     0.500000       -0.700000        0.128985
     0.600000       -0.700000        0.113552
     0.700000       -0.700000        9.400019E-02
     0.800000       -0.700000        6.945068E-02
     0.900000       -0.700000        3.867569E-02
      1.00000       -0.700000         0.00000
     -1.00000       -0.600000         0.00000
    -0.900000       -0.600000        4.578741E-02
    -0.800000       -0.600000        8.317228E-02
    -0.700000       -0.600000        0.113552
    -0.600000       -0.600000        0.138058
    -0.500000       -0.600000        0.157568
    -0.400000       -0.600000        0.172748
    -0.300000       -0.600000        0.184095
    -0.200000       -0.600000        0.191962
    -9.999999E-02   -0.600000        0.196590
     1.490116E-08   -0.600000        0.198118
     0.100000       -0.600000        0.196590
     0.200000       -0.600000        0.191962
     0.300000       -0.600000        0.184095
     0.400000       -0.600000        0.172748
     0.500000       -0.600000        0.157568
     0.600000       -0.600000        0.138058
     0.700000       -0.600000        0.113552
     0.800000       -0.600000        8.317228E-02
     0.900000       -0.600000        4.578741E-02
      1.00000       -0.600000         0.00000
     -1.00000       -0.500000         0.00000
    -0.900000       -0.500000        5.130390E-02
    -0.800000       -0.500000        9.390321E-02
    -0.700000       -0.500000        0.128985
    -0.600000       -0.500000        0.157568
    -0.500000       -0.500000        0.180491
    -0.400000       -0.500000        0.198419
    -0.300000       -0.500000        0.211868
    -0.200000       -0.500000        0.221216
    -9.999999E-02   -0.500000        0.226723
     1.490116E-08   -0.500000        0.228542
     0.100000       -0.500000        0.226723
     0.200000       -0.500000        0.221216
     0.300000       -0.500000        0.211868
     0.400000       -0.500000        0.198419
     0.500000       -0.500000        0.180491
     0.600000       -0.500000        0.157568
     0.700000       -0.500000        0.128985
     0.800000       -0.500000        9.390321E-02
     0.900000       -0.500000        5.130390E-02
      1.00000       -0.500000         0.00000
     -1.00000       -0.400000         0.00000
    -0.900000       -0.400000        5.552766E-02
    -0.800000       -0.400000        0.102157
    -0.700000       -0.400000        0.140923
    -0.600000       -0.400000        0.172748
    -0.500000       -0.400000        0.198419
    -0.400000       -0.400000        0.218585
    -0.300000       -0.400000        0.233757
    -0.200000       -0.400000        0.244326
    -9.999999E-02   -0.400000        0.250561
     1.490116E-08   -0.400000        0.252622
     0.100000       -0.400000        0.250561
     0.200000       -0.400000        0.244326
     0.300000       -0.400000        0.233757
     0.400000       -0.400000        0.218585
     0.500000       -0.400000        0.198419
     0.600000       -0.400000        0.172748
     0.700000       -0.400000        0.140923
     0.800000       -0.400000        0.102157
     0.900000       -0.400000        5.552766E-02
      1.00000       -0.400000         0.00000
     -1.00000       -0.300000         0.00000
    -0.900000       -0.300000        5.865262E-02
    -0.800000       -0.300000        0.108280
    -0.700000       -0.300000        0.149812
    -0.600000       -0.300000        0.184095
    -0.500000       -0.300000        0.211868
    -0.400000       -0.300000        0.233757
    -0.300000       -0.300000        0.250269
    -0.200000       -0.300000        0.261789
    -9.999999E-02   -0.300000        0.268593
     1.490116E-08   -0.300000        0.270843
     0.100000       -0.300000        0.268593
     0.200000       -0.300000        0.261789
     0.300000       -0.300000        0.250269
     0.400000       -0.300000        0.233757
     0.500000       -0.300000        0.211868
     0.600000       -0.300000        0.184095
     0.700000       -0.300000        0.149812
     0.800000       -0.300000        0.108280
     0.900000       -0.300000        5.865262E-02
      1.00000       -0.300000         0.00000
     -1.00000       -0.200000         0.00000
    -0.900000       -0.200000        6.080576E-02
    -0.800000       -0.200000        0.112506
    -0.700000       -0.200000        0.155961
    -0.600000       -0.200000        0.191962
    -0.500000       -0.200000        0.221216
    -0.400000       -0.200000        0.244326
    -0.300000       -0.200000        0.261789
    -0.200000       -0.200000        0.273989
    -9.999999E-02   -0.200000        0.281200
     1.490116E-08   -0.200000        0.283586
     0.100000       -0.200000        0.281200
     0.200000       -0.200000        0.273989
     0.300000       -0.200000        0.261789
     0.400000       -0.200000        0.244326
     0.500000       -0.200000        0.221216
     0.600000       -0.200000        0.191962
     0.700000       -0.200000        0.155961
     0.800000       -0.200000        0.112506
     0.900000       -0.200000        6.080576E-02
      1.00000       -0.200000         0.00000
     -1.00000       -9.999999E-02     0.00000
    -0.900000       -9.999999E-02    6.206776E-02
    -0.800000       -9.999999E-02    0.114985
    -0.700000       -9.999999E-02    0.159572
    -0.600000       -9.999999E-02    0.196590
    -0.500000       -9.999999E-02    0.226723
    -0.400000       -9.999999E-02    0.250561
    -0.300000       -9.999999E-02    0.268593
    -0.200000       -9.999999E-02    0.281200
    -9.999999E-02   -9.999999E-02    0.288655
     1.490116E-08   -9.999999E-02    0.291122
     0.100000       -9.999999E-02    0.288655
     0.200000       -9.999999E-02    0.281200
     0.300000       -9.999999E-02    0.268593
     0.400000       -9.999999E-02    0.250561
     0.500000       -9.999999E-02    0.226723
     0.600000       -9.999999E-02    0.196590
     0.700000       -9.999999E-02    0.159572
     0.800000       -9.999999E-02    0.114985
     0.900000       -9.999999E-02    6.206776E-02
      1.00000       -9.999999E-02     0.00000
     -1.00000        1.490116E-08     0.00000
    -0.900000        1.490116E-08    6.248359E-02
    -0.800000        1.490116E-08    0.115803
    -0.700000        1.490116E-08    0.160764
    -0.600000        1.490116E-08    0.198118
    -0.500000        1.490116E-08    0.228542
    -0.400000        1.490116E-08    0.252622
    -0.300000        1.490116E-08    0.270843
    -0.200000        1.490116E-08    0.283586
    -9.999999E-02    1.490116E-08    0.291122
     1.490116E-08    1.490116E-08    0.293616
     0.100000        1.490116E-08    0.291122
     0.200000        1.490116E-08    0.283586
     0.300000        1.490116E-08    0.270843
     0.400000        1.490116E-08    0.252622
     0.500000        1.490116E-08    0.228542
     0.600000        1.490116E-08    0.198118
     0.700000        1.490116E-08    0.160764
     0.800000        1.490116E-08    0.115803
     0.900000        1.490116E-08    6.248359E-02
      1.00000        1.490116E-08     0.00000
     -1.00000        0.100000         0.00000
    -0.900000        0.100000        6.206776E-02
    -0.800000        0.100000        0.114985
    -0.700000        0.100000        0.159572
    -0.600000        0.100000        0.196590
    -0.500000        0.100000        0.226723
    -0.400000        0.100000        0.250561
    -0.300000        0.100000        0.268593
    -0.200000        0.100000        0.281200
    -9.999999E-02    0.100000        0.288655
     1.490116E-08    0.100000        0.291122
     0.100000        0.100000        0.288655
     0.200000        0.100000        0.281200
     0.300000        0.100000        0.268593
     0.400000        0.100000        0.250561
     0.500000        0.100000        0.226723
     0.600000        0.100000        0.196590
     0.700000        0.100000        0.159572
     0.800000        0.100000        0.114985
     0.900000        0.100000        6.206776E-02
      1.00000        0.100000         0.00000
     -1.00000        0.200000         0.00000
    -0.900000        0.200000        6.080576E-02
    -0.800000        0.200000        0.112506
    -0.700000        0.200000        0.155961
    -0.600000        0.200000        0.191962
    -0.500000        0.200000        0.221216
    -0.400000        0.200000        0.244326
    -0.300000        0.200000        0.261789
    -0.200000        0.200000        0.273989
    -9.999999E-02    0.200000        0.281200
     1.490116E-08    0.200000        0.283586
     0.100000        0.200000        0.281200
     0.200000        0.200000        0.273989
     0.300000        0.200000        0.261789
     0.400000        0.200000        0.244326
     0.500000        0.200000        0.221216
     0.600000        0.200000        0.191962
     0.700000        0.200000        0.155961
     0.800000        0.200000        0.112506
     0.900000        0.200000        6.080576E-02
      1.00000        0.200000         0.00000
     -1.00000        0.300000         0.00000
    -0.900000        0.300000        5.865262E-02
    -0.800000        0.300000        0.108280
    -0.700000        0.300000        0.149812
    -0.600000        0.300000        0.184095

            

            
            
            

    

        

	
    

        
Best Answer
    

    

								

								
It is easier not to generate xyu like that. Instead, output x, then output y, then output u. Then on the MATLAB side,
   surf(x, y, reshape(u, length(x), length(y)) )
For this to work properly, when you output u, output it down the columns rather than across the rows. Or output it in matrix form with multiple columns per line.
						    
						
		
    
        

    

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     1.00000     1.00000     1.00000     0.00000     0.00000     0.00000     0.00000     0.00000     0.00000     0.00000     1.00000
     2.00000     2.00000     1.03000     0.00000   550.00000     0.00000     0.00000     0.00000     0.00000     0.00000     1.00000
     3.00000     3.00000     1.00000     0.00000     0.00000     0.00000   350.00000     0.00000     0.00000     0.00000     1.00000
     4.00000     3.00000     1.00000     0.00000     0.00000     0.00000   300.00000     0.00000     0.00000     0.00000     1.00000
     5.00000     3.00000     1.00000     0.00000     0.00000     0.00000   250.00000     0.00000     0.00000     0.00000     1.00000
     6.00000     3.00000     1.00000     0.00000     0.00000     0.00000   100.00000     0.00000     0.00000     0.00000     2.00000
     7.00000     3.00000     1.00000     0.00000     0.00000     0.00000   100.00000     0.00000     0.00000     0.00000     3.00000
     8.00000     2.00000     1.05000     0.00000   100.00000     0.00000     0.00000     0.00000     0.00000     0.00000     2.00000
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Answer 1

It is easier not to generate xyu like that. Instead, output x, then output y, then output u. Then on the MATLAB side,

   surf(x, y, reshape(u, length(x), length(y)) )

For this to work properly, when you output u, output it down the columns rather than across the rows. Or output it in matrix form with multiple columns per line.