CODEWITHSUNDEEP
arraystypesfortranfortran90gfortran
Eddie E Massey III
Eddie E Massey III

Reputation: 383

How do you return a typed array in Fortran?

I made a type in fortran called waveform and I made a function that reads through a file and makes an array of waveform types.

I want the function to return my waveform array, but I can't seem to figure out how to return the final array.

Below is my function

 !@param none                                                                                           
 !@return array of the configuration file                                                               

  function getWilloughby()


integer::it !iterator for do loop                                                                    
integer::size = 56661 !Expected dimension of waveforms array                                         

integer::io

real::x 
real::y 

real::lat

real::windspeed !Wind speed at that point                                                            
real::a !Willougby A parameter                                                                       

real::startX
real::startY

real::data(600)


type(waveform), allocatable ::waveforms(:) !An array to hold all waveforms                           
type(waveform), allocatable ::waveformsOut(:) !An array to hold all waveforms                        
allocate(waveforms(size))
allocate(waveformsOut(size))



open(1, file="Willoughby56_530-w.txt")

!Load configuration parameters                                                                       
read(1,*) windSteps, windStart, windInc, xSteps, ySteps, yInc, xInc, lat, xStart, yStart

write(*,*) "The wind parameters are" ,windStart, windSteps, windInc


write(*,*) "Loading Model Waveform data"

it = 1 !Iterator for do loop                                                                         

do
   it  = it + 1
   read(1,*, IOStat = io) x, y, windspeed, lat, a , startX, startY, data

   if(io > 0) then
      write(*,*) 'Check input. There was an error parsing the file'
      write(*,*) 'The error number is:' ,io
      exit
   else if (io < 0) then

      write(*,*) 'Finished reading the Willoughby configuration file'
      exit
   else
      !Read the Willoughby config file                                                               
      !Load each model waveform into a waveform type                                                 
      !Place the waveform into the waveforms array                                                   
      !write(*,*) "Waveform:", x, y, windspeed, lat, a, startX, startY, data                         
      waveforms(it)%x = x

      waveforms(it)%y = y
      waveforms(it)%windspeed = windspeed
      waveforms(it)%lat = lat
      waveforms(it)%startX = startX
      waveforms(it)%startY = startY
      waveforms(it)%data = data
      !write(*,*) waveforms(it)%data                                                                 
   end if
end do

write(*,*) waveforms


  end function getWilloughby

When I want to call the function from my main program like so, I get an error:

type(waveform), allocatable::modelwaveforms(:) 
modelwaveforms = getWilloughby()

Gfortran Compier error:

  modelwaveforms = getWilloughby()
               1
  Error: Can't convert REAL(4) to TYPE(waveform) at (1)

If I change the modelwaveforms(:) array into a REAL array like the error says, it compiles, but only gives me one value from the array.

What am I doing wrong?

Upvotes: 1

Views: 134

Answers (1)

casey
casey

Reputation: 6915

You are not defining a type for getWilloughby so it is defaulting to real under implicit typing (use implicit none to turn off implicit typing so you'll get an error about not defining the return type).

To fix this you will need to define the return type, e.g.:

type(waveform), allocatable, dimension(:) :: getWilloughby ! return value

If you have a different variable that you want to be returned by the function, you can define the function as:

function getWilloughby() result(someOtherVariableName)

and make sure that someOtherVariableName is of type type(waveform)

and if the function is not in a module, you will need to define an explicit interface in the Fortran file that calls the function, e.g.

interface
  function getWilloughby()
    type(waveform), allocatable, dimension(:) :: getWilloughby
  end function
end interface

Upvotes: 2

Related Questions