I need to output a matrix with FORTRAN. I have a working code that calculates the values, but instead of a matrix, I get single a column. The matrix is huge, ixj = ~2000x2000.

Here is my sample code:

```
  open(19, file="results1.txt", status="old", position="rewind", 
 & action="write") 

  do j=0,p
  do i=0,o
  write(19,*) mat_user_yield_surface(d, eps(i), deps(j), 200.0d0)
  end do
  end do

  close(19)

```