This page is designed to enable the easy download, installation, and running of MinGW-3.1.0-1. (Running gcc -v should reveal the compiler is gcc version 3.2.3.)

Download and Installation:

In order to install this on your computer you need to have administrator access to your machine (which you have automatically on your personal machines, but probably not if it is a University owned computer). If you do not normally have administrator access you will want to make sure that you set it so that all users have full access to the MinGW folder on the C drive.

1. Download the latest executable file: http://prdownloads.sf.net/mingw/MinGW-3.1.0-1.exe?use_default=umn saving it in whatever temporary directory you usually save such files in. (It is about 15mb, so it may take a while on a dial-up connection.)

2. Run the executable...
   • clicking Next if you really want to install
   • clicking Yes after reading and agreeing to the License Agreement
   • clicking Next when it wants to set it up in the C:\MinGW\ directory
   • clicking Next when it asks if you want the default architecture...
   • and finally clicking Install

3. Set your computers PATH variable to c:\MinGW\bin;%PATH%
   
   
   • For Windows 95/98/Me:
     These variables are set in the autoexec.bat file, which is stored in the root directory of your hard disk. So, you need to edit this file and add to the line:
     PATH=C:\MINGW\bin;%PATH%
     You can do this by opening this file in Notepad or any other editor, adding the two lines at the end, and then saving the changes.
     
     
   • For the Windows NT/2000/XP: These variables can be set by going to the Control Panel, selecting System, and then locating the environment (or advanced, environment) section. You need to add a new variable named PATH (or edit it if already present) and set its value to C:\MINGW\bin;%PATH%
   
   If there is already another path variable there you add this code to it by separating it from the previous one with a semi-colon (;). I found that it was also necessary to remove a previous PATH entry for a Fortran compiler I no longer used.

4. Restart your computer so the changes can take place

Compiling Fortran:

To see if it all works we can try compiling and running a short program. At first, anyway, we will store all of our programs in a directory called Programs inside the MinGW directory.

1. Use either My Computer or Explorer to make a directory called Programs inside the C:\MinGW directory. Then you can close whatever you used to make that directory.

2. Open either Notepad or WordPad and copy into it the following code¹:

     program Convert
     implicit none
     ! -----------------------------------------------Declare
     real*4 tempC, tempF, FACTOR
     integer*2 ZERO_SHIFT
     parameter (ZERO_SHIFT = 32, FACTOR = 5./9.)
     ! -----------------------------------------------Input
     print*, "Enter the temperature in Fahrenheit ..."
     read*, tempF
     ! -----------------------------------------------Compute
     tempC = FACTOR * (tempF - ZERO_SHIFT)
     ! -----------------------------------------------Output
     print*, "The corresponding Centigrade temperature is "
     print*, tempC, " degrees."
     end
   

   and save it as convert.for. Note that you will need to choose the option All Files for Save as Type in Notepad. If you are using WordPad you will need to choose Text Document or something similar.

3. Choose Run under the Start menu and open command or cmd.

4. Get to your directory using:

   c:
   cd c:\mingw\programs
   

5. Type g77 -ffree-form convert.for -o convert.exe

6. Type convert

Making DLLs:

The following instructions will construct a DLL (a program you can call from R) to raise an entire string of real numbers to some integer power.

1. Save the following code² in the c:\MinGW\Programs directory as testit.f :

         subroutine TESTIT(x,n,m)
         dimension x(n)
         do 10 i=1,n
   10      x(i)=x(i)**m
         end
   

   Notice that this is a subroutine and not a function. Therefore it modifies values that were sent to it and returns them (x is changed in this case). In particular the name of that variable has to be included in the subroutine line.

2. Use the DOS window to go to the c:\MinGW\Programs directory.

3. Run the following:

   g77 -O2 -c testit.f
   dllwrap --export-all-symbols testit.o -o testit.dll
   

To run this subroutine from R (raising each of the numbers 1 to 5 to the power -2) you would run the following:

dyn.load("c:/MinGw/Programs/testit.dll")
.C("testit_",as.single(1:5),as.integer(5),as.integer(-2))[[1]][1:5]

The first line loads the dll and the second one runs it. Notice that we need to specify what format the subroutine is reading the variables in as. (There is also a .Fortran function but it was behaving oddly in some cases when I tried it out).

A function to call this routine might be a bit easier to use:

testit<-function(x=1.0,m=1){
  if (is.loaded("testit_")==T){
    n<-length(x)
    return(.C("testit_",as.single(x),as.integer(n),as.integer(m))[[1]][1:n])
  }
  else{
    warning("testit.dll was not loaded")
    NULL
  }
}

You would then use testit(1:5,-2) to replicate the above answer.

Credits:

The information and sample programs on this page were pilfered liberally from:

• http://www.mingw.org/
• http://www.colicsoft.com/pub/Installing_MinGW.htm
• ¹ Professor Hamzeh Roumani http://www.cs.yorku.ca/~roumani/fortran/ at York University
• ² Venables, W.N. & B.D. Ripley. S Programming. New York: Springer-Verlag, 2000.

Created: 1/16/04 - B. Habing
Last Updated: 1/17/04 - B.Habing

This page ( www.stat.sc.edu/~habing/courses/740/mingw.html) is maintained by Brian Habing (habing@stat.sc.edu). The views and opinions expressed in this page are strictly those of the page author. The contents of the page have not been reviewed or approved by the University of South Carolina.