REGISTERING AND OBTAINING FIT2D

Registering as a FIT2D User

FIT2D is available free of charge in return of an undertaking for appropriate acknowledgement of use of the program and the methods. Use of FIT2D for commercial purposes is not allowed.

The "Conditions of Use" are intended to allow freedom of use for personal academic research provided suitable acknowledgement of the program and methods is given.

Previously, a "software key" was used to control use of the program to registered users, this has now been removed from all versions. This means that users can use the program immediately, and can change computer systems without needing new keys, but has the disadvantage that there is now no record of who is using the program.

Using a Web Browser to Obtain FIT2D

The FIT2D home page is at URL:

http://www.esrf.fr/computing/scientific/FIT2D.

Here there are links to obtain documentation and the available executable files.

Obtaining FIT2D by aftp

FIT2D executables for various machine and operating system types can be obtained by anonymous ftp from www.esrf.fr (COMPAQ-ALPHA TRU64 V4, HP-800 HP-UX V10, IBM RS6000 AIX 4, Silicon Graphics Irix 6.5, PC Linux, SunOS V5 (Solaris), and Windows (95/98/ME/NT/2000 versions are presently available.)

To obtain executable files, PostScript documentation, and a "Conditions of Use" form use the following (or similar):

> ftp www.esrf.fr

user name> anonymous
enter user name and machine as password>

> cd pub
> cd expg
> cd FIT2D

> ls

(This will list the files in the directory.)

> bin
> mget fit2d*

(Here you will be prompted for the different files starting with "fit2d" enter "y" for the required executable.)

> ascii
> mget fit2d

(Here you will be prompted for the different files starting with "fit2d" enter "y" for the required PostScript file (.ps).)

> quit

(To end the ftp session.)

Having transferred the executable file by ftp you will probably want to change the file-name and have to change the file permission to make it "executable". e.g.

> mv fit2d_10.30_alpha_OSFV4.0 fit2d
> chmod +x fit2d

Now you should be able to run FIT2D:

> fit2d

This should open a window for graphics output, and produce "banner" text and other text in the terminal window. Without the "software key" the program will not enter the main menu.

Andy Hammersley

APPENDIX A: System Requirements

Memory Requirements

FIT2D uses allocation of virtual memory at run time to allow almost unlimited flexibility in the size of images which may be processed. The limits are generally set by the limitations of the underlying computer system and not by FIT2D. Within very flexible limits the user defines the sizes of work arrays at the start-up of FIT2D. Since some images may be very large it is useful to understand the storage needs.

Normally FIT2D stores 2 arrays: the current data array and the "memory". Each uses 4-byte reals as the storage element per pixel. Additionally the "FIT" sub-menu creates a "masking" array which is 1-byte per pixel. This is used for fitting operations and for powder diffraction re-binning. Thus in general 9-bytes per pixel may be used. The program uses a small number of other arrays, also allocated dynamically e.g. for image display. So typically 5 Mbytes are needed for FIT2D even with very small data arrays. An approximate formula for the total memory requirement is:

Required memory = 9 * X_DIMENSION * Y_DIMENSION + 5 Mbytes

e.g. If X_DIMENSION = Y_DIMENSION = 1024, about 14 Mbytes total memory is required.

If X_DIMENSION = 2048, Y_DIMENSION = 4096, about 77 Mbytes is needed.

This total memory can be virtual memory and does not need to be RAM, but it is clearly advisable to be able to able to store at least one complete data-set in RAM.

If this causes problems it is possible to work with only the current data array i.e. only 4-bytes per pixel, and it is possible to work with only a sub-region of the data, or with the data rebinned into a smaller array.

For the second example it should be recommended to have 96 Mbyte of RAM (some extra memory for other users), and about 80 Mbyte of swap space per FIT2D process or similar analysis program. So perhaps 200-300 Mbytes of swap should be permanently established in a "swap file". (Using temporarily allocated swap space will cause problems as the temporary disk space gets filled up. One day a previously running program will no longer run ! Disk space is so cheap these days it's foolish to try to economise on swap space.)

Time Requirements

It is almost impossible to define time limits, owing to the flexible and interactive nature of FIT2D. Probably most users will use FIT2D for about 0.5 hours, but some will use it for much shorter or much longer periods. "Batch" style processing is possible which could involve longer periods.

This page has been produced by Andy Hammersley (E-mail: hammersley@esrf.fr). It is subject to further modification. If you have helpful suggestions, please send them to me.