You want to use allocatable arrays: PROGRAM mytest IMPLICIT NONE INTEGER :: i, j, k, mysum REAL, DIMENSION(:,:), allocatable :: c !<- c is allocatable, rank 2 ! Let array c be a k-by-k**2 array ! Determine k within the program by some means…for example, mysum=0 DO i=1, 3 mysum=mysum+1 END DO k=mysum WRITE(*,*) “k=”, … Read more
As already answered, you need to specify widths. Something like ES14.5 might work well for the floating point format. There is a short cut for the integer format: I0 will cause the compiler to use the number of digits needed.
It is call action(mySubX) provided action looks as subroutine action(sub) !either – not recommmended, it is old FORTRAN77 style external sub !or – recommended interface subroutine sub(aA, aB) integer,intent(…) :: aA, aB end subroutine end interface ! NOT BOTH!! call sub(argA, argB) provided action knows what to put there as argA, argB to represent aA, … Read more
Under the rules of current Fortran (Fortran 2008, but this is the same for when C interoperability was introduced in Fortran 2003), a Fortran procedure is not interoperable with C if it has an assumed shape dummy argument (other restrictions also apply). In your code degC, the dummy argument in the function DegCtoF, declared as … Read more
One possible solution has already been presented to you which uses a “dummy variable”, but I just wanted to add that you don’t even need a dummy variable, just a blank read statement before entering the loop is enough: open(18, file=”m3dv.dat”) read(18,*) do … The other answers are correct but this can improve conciseness and … Read more
character*40 :: string is a character string of length 40 character :: string*40 is the same character(len=40) :: string is also a character string of length 40 character :: string(40) is an array of 40 character strings of length 1 character*40 :: string(40) is an array of 40 character strings of length 40 character :: … Read more
intent(inout) and intent(out) are certainly not the same. You have noted why, although you don’t draw the correct conclusion. On entering the subroutine useless a is undefined, rather than defined. Having a variable “undefined” means that you cannot rely on a specific behaviour when you reference it. You observed that the variable a had a … Read more
There are no templates in Fortran and hence no STL. You can try FLIBS for some generic libraries. It generally uses transfer() tricks to achieve generic programming. There is a preprocessor which adds some templates to Fortran and comes with some small STL, you can try that too named PyF95++. If you have access to … Read more
I hope a real Fortran programmer comes along, but in the absence of better advice, I would only specify the shape and not the size of x(:), use a temporary array temp(size(x)), and make the output y allocatable. Then after the first pass, allocate(y(j)) and copy the values from the temporary array. But I can’t … Read more
Here’s a minimum working example. I used gfortran and wrote the compile commands directly into the setup file. gfunc.f90 module gfunc_module implicit none contains subroutine gfunc(x, n, m, a, b, c) double precision, intent(in) :: x integer, intent(in) :: n, m double precision, dimension(n), intent(in) :: a double precision, dimension(m), intent(in) :: b double precision, … Read more