Computational Physics 2006

Access to PWF Linux from home

Despite oft-repeated advice that this project is best completed before the vacation, several people appear to believe that this is a relevant point to discuss.

Assuming access to a computer and some form of internet connection, the advice given in the network access page stands.

Downloading the NAG compiler will not work from outside Cambridge, and a version downloaded from within Cambridge might work (though it should not!) but will certainly need network access in order for the licence manager to function. Without access to the licence manager, the compiler will refuse to run.

It is possible to compile code on linux.phy.pwf.cam.ac.uk and then run it on one's personal Linux machine whilst not dialed up. The recipe is:

• Compile the program on linux.phy.pwf using `f95 -Bstatic', e.g.
  f95 -Bstatic -o myprog myprog.f90 -lnag
• Copy the program to your own machine using scp on your machine, e.g.
  scp -C spqr1@linux.phy.pwf.cam.ac.uk:directory/myprog .
  (Note final `.' on above line, and replace `spqr1' by your user id and `directory/myprog' by the name of the executable to fetch, relative to your home directory, i.e. simply `myprog' if you are not using subdirectories)
• Run the executable as usual (./myprog) on your own machine. For this point a network/modem connection is not necessary.

Beware that the executables compiled in this fashion will be rather large (about 2MB), and the compiler will produce the unexpected warning:

 /usr/local/lib/NAGWare/libf96.a(open.o): In function
`__NAGf90_open': open.o(.text+0x7f5): the use of `tmpnam' is
dangerous, better use `mkstemp' 

In order to reduce download times, after compiling one can type strip myprog which should reduce its size significantly. The use of `-C' with scp ensures that decent compression is achieved over a dial-up link: it is unnecessary with a fast College connection.

It is not possible to run a program compiled under Linux on a computer running Windows.