Subsections

• Graphics User Interface (GUI) Start-Up
• ``Keyboard'' Interface Start-Up

Start-up of FIT2D

When FIT2D is started you should see a screen of text similar to this one³on the terminal screen from where you typed fit2d:

                      --------------------------------
                      PROGRAM  FIT2D  Version: V12.008
                      ________________________________

        Copyright 1987-2004 Andy Hammersley / ESRF (hammersley@esrf.fr)

FIT2D: 2-D Detector Calibration/Correction; File re-formatting; 2-D Fitting

                      YOU CAN ALWAYS ENTER:   ?
              FOR FURTHER EXPLANATION OF REQUIRED INPUT

                    No commercial software used !
See ``CHANGES'' (keyboard menu) for important changes
 
 
!!! NOTE: ``SYMBOLS'' commands replaced with ``VARIABLES''
!!! commands in "KEYBOARD" menu

Note the version number that you are using⁴.

At the same time the graphics window should be filled with the FIT2D graphics ``banner'' and the FIT2D logo and four buttons (unless FIT2D has been started in the ``keyboard'' interface mode).

Graphics User Interface (GUI) Start-Up

The default interface to FIT2D is the graphics user interface (GUI) which uses the graphics window with ``point and click'' user interaction.

The areas with yellow background and blue text are graphically active i.e. they can be clicked upon to select a command, or in later forms a file name.

In this case (see front cover, Page 1) there are four buttons:

• CONDITIONS This explains the conditions of use.

• I ACCEPT To accept the conditions of use, and enter the main interface selection menu.

• DON'T ACCEPT To exit FIT2D immediately.

• HELP For general explanation on the graphics user interface.

Now and at any time the graphics window is active i.e. the cursor and cross-hair can be moved with the mouse (or other graphics pointing device), the graphics window can be resized by dragging on one of the corners of the window. After user re-sizing FIT2D will re-size the window to the largest window with the same aspect ratio as previously within the user defined region, although a minimum size is specified below which the window cannot be reduced.

To enter FIT2D you must click on the I ACCEPT button which conveys acceptable of the ``Conditions of Use'' which are detailed within the text form obtained by clicking on the CONDITIONS button.

If you don't accept the ``Conditions of Use'' then click on the DON'T ACCEPT button and FIT2D will exit immediately. (This is also useful when you remember that you should be doing something else, or want to work from a different directory, etc.)

After the I ACCEPT button has been clicked the following form should appear (unless command-line options have been used to specify the equivalent information; see Section 20, Page ):

Figure 1: FIT2D Program Array Dimensions Form

The four vertical buttons allow the size (number of elements) of the internal program arrays and the number and type of arrays to be specified. Unlike many other programs FIT2D is completely versatile in the size of images (and 1-D data-sets) which can be treated (although system constraints will impose limits at some level).

Thus when FIT2D is started it is necessary to specify the size of the internal arrays used to store data. Normally you will want the arrays to be as large as the data to be input. The precise size will vary from application to application. The arrays can be larger or smaller than the data input from file. If the arrays are smaller then not all of the data can be input at full resolution. If the arrays are bigger, then only the region input will be used, but sometimes it can be useful to specify array sizes larger than the size of the input data.

The X-DIMENSION button allows the number of pixels in the first array dimension (horizontal as displayed) to be specified.

The Y-DIMENSION button allows the number of pixels in the second array dimension (vertical as displayed) to be specified.

The MEMORY button allows the creation of ``memory'' arrays or not. All operations except for very basic display require the ``memory'' to exist, so by default this boolean variable has the value ``YES''. Normally this should not be changed. Only if there is a problem of insufficient computer memory, and only image display is required would this be set to ``NO''.

The VARIANCES button allows variance arrays to be created or not. Variance arrays are necessary if error propagation is to be carried out [3], but this nearly doubles total computer memory requirements and will slow down many operations. This should only be selected if error propagation is being used in the data analysis.

The other buttons (blue text on a yellow background) are general forms buttons. See Section 4.3, Page  for general information on the interactive graphical forms.

When the form values are correct, click on the O.K. button and the program array will be created and the main interfaces menu will appear:

Figure 2: FIT2D Scientific Interfaces Main Menu

Assuming the ``Scientific Interfaces'' menu has appeared you have entered FIT2D and are ready to select one of the graphical interfaces or the KEYBOARD INTERFACE. These are described below.

``Keyboard'' Interface Start-Up

When FIT2D is started-up in the ``keyboard'' interface mode e.g. by using the -key option on the command-line (see Section 20, Page  for further information), or when the graphics system cannot start-up for some reason, the line:

X DIMENSION FOR ARRAYS (Range: 1 to 1000000) [512]:

appears beneath the FIT2D banner text within the terminal window.

This is a prompt line for user input. If you click inside the terminal window⁵ and enter a question mark (?), you should see the following text:

X DIMENSION FOR ARRAYS (Range: 1 to 1000000) [512]:?
Here you are asked to define the size of the program arrays.  These will
be used to store data "inside" FIT2D.  Normally you will want the arrays
to be at least as large as the image data to be input. If the dimensions
are larger this does little harm,  but is wasteful of system  resources.
If the arrays are smaller then not all of  an image can be input at full
resolution.  Some input options allow an image to  be re-binned on input
or for a sub-region of the image to be input.

This prompt and the next prompt:

Y DIMENSION FOR ARRAYS (Range: 1 to 1000000) [512]:

define the sizes of the internal arrays which are used to store data. As images can vary in size, FIT2D allows great flexibility in the size of data that can be input. Very large images may be treated, but the computer system on which FIT2D is running may not be set-up to allow enough memory to be used. Users are recommended to use as little memory as they need. The program arrays do not need to be exactly the size of input data: if they are bigger the extra space is not used initially, but may be used by certain commands; if the arrays are smaller than images to be input, then only part of the image will be input, or with some input options there is the choice to ``re-bin'' the data on input.

The next prompt allows you to create variance arrays or not:

CREATE VARIANCE ARRAYS [NO]:

If you don't know whether or not to create variance arrays it is best not to create them (the default is not to create them). Creating variance arrays doubles the requirements for virtual memory, and is only useful for a few specialist commands.

Assuming no error occurs the next prompt is:

Main menu: ENTER COMMAND [INPUT DATA]:

You have now started FIT2D and entered the ``Main menu''. See Section 14, Page  for help on general usage of the FIT2D ``keyboard'' interface .

If instead you get an message like the following:

STATUS: The error was identified in module:
IO: Input/Output and Status

STATUS: Position where error condition was identified
Subroutine IO_MALLOC V0.1

STATUS: The error condition has been classified as:
Bad memory allocation: Memory allocation failed
RESET ``status'' [YES]:

then the memory allocation has failed i.e. the system cannot give FIT2D as much virtual memory as you have requested. This means that the program arrays have not been created and normal operations will not work. It may be possible to re-define smaller memory requirements using the DIMENSIONS command (See Section 15.28, Page ), or to ask other users to stop some processes to free more virtual memory, or to ask the system administrator to increase the system quotas.