# MatLab2Fortran question

1. Jun 10, 2009

### quZz

What is the shortest way to convert this MatLab line

[x,y] = meshgrid(0:hx:xm, 0:hy:ym);

to F90?

2. Jun 10, 2009

### minger

Code (Text):

PROGRAM create_arrays

IMPLICIT NONE

INTEGER :: i,j,hx,hy,mx,my
REAL :: xcount,ycount,xint,yint
REAL,DIMENSION(:,:),ALLOCATBLE :: x,y

xcount = 0.0
ycount = 0.0
xint = REAL( (mx-1)/hx )
yint = REAL( (my-1)/hy )
ALLOCATE( x(mx/hx),&
y(mx/hx) )

DO i=0,xm,hx
DO j=0,ym,hy
x(i,j) = xcount
y(i,j) = ycount
ycount = ycount + yint
END DO
ycount = 0.0
xcount = xcount + xint
END DO

DEALLOCATE( x,y )

END PROGRAM

Note that for laziness I'm assuming that you'll ALWAYS be starting from zero. Also, the allocate will only work if the maximum divided by the "stride" is an integer.

Rather than specify it like matlab does with the meshgrid command (I had to look it up), I would specify and a range and a number of points. That way the allocate is easy (allocate to number of points), and the interval is simply the range divided by the number of points.

Either way, it'll get you close. You'll need to put the actual variables in there somehow, by either direct specification or by read/write commands; up to you.

3. Jun 11, 2009

### quZz

Thank you, minger, but I think i found a shorter way: instead of the do cycle

x = SPREAD((/(hx*j, j = 0,Nx)/), 1, Nx+1)
y = SPREAD((/(hy*j, j = 0,Ny)/), 2, Ny+1)

4. Jun 11, 2009

Very nice!