The program has been written such that it should handle almost any typing error when giving commands and hopefully all errors that result from calculation with erroneous data. When an error is found an error message is displayed that should get you back on track. See the manual for a complete list of error messages.
Error messages concerning the command language are explained in the -> command language section of the online help. Application specific commands are described here and are grouped as follows:
APPL Errors specific to PDFFIT structure functions PDF Errors specific to PDFFIT PDF calculation and fit func.Each error message is displayed together with the corresponding category <cccc> and the error number <numb> in the form:
****CCCC****message **** numb ****
Type help error <cccc> <numb> to get an explanation for the error
message and hints for possible steps to correct the situation.
In the default mode PDFFIT returns the standard prompt and you can continue the execution from this point. You can set the error status to "exit" by the ==>'set' command. In this case PDFFIT terminates if an error is detected. This option is useful to terminate a faulty sequence of commands when running PDFFIT in the batch mode of your operating system.
This category lists error messages that are specific to structure related functions of PDFFIT.
Error : -2 : Improper limits for atom number
Either of the upper or lower limits used on the 'append' command is
outside the range of atoms present in the crystal. Check whether
the limits are both positive, the upper limit is higher or equal to
the lower limit and whether both limits are less or equal to the
number of atoms present in the crystal. The number of atoms in the
crystal can be checked with the command: "eval n[1]".
Error : -3 : No atoms selected yet
The plot and waves can only be run for selected atoms. Use the 'select'
command to select individual atom types or to select all atoms present
in the crystal.
Error : -7 : Unknown space group symbol
The crystal file contains an unknown space group. Check the spelling of
the space group symbol. The allowed space groups are all 230 space
groups in the Int. Tables for Crystallography plus the space groups
given for alternative settings and cell choices of the monoclinic
space groups.
Error : -10 : Too many Atoms in crystal
The maximum number of atoms that can be stored in the structure
is determined by the parameter NMAX in the file "crystal.inc".
By inserting new atoms or by defining too large a crystal on the
'read' command, this number was exceeded. If necessary, change the
value of the parameter NMAX and recompile the program.
Error : -12 : Number of points must be > zero
The value of the parameter given on the 'abs' or 'ord' command is
less than one. This value represents the number of data points
calculated along the respective direction.
The value must be at least one or higher.
Error : -14 : Invalid space group & lattice constants
While reading a new cell the program checks the space group and the
lattice constants for consistency. Either a space group was given
that is not included in the program, or the lattice constants do
not fulfill the constraints imposed by the space group. Check the
space group symbol and the lattice constants given in the input file.
Error : -19 : Atom number outside limits
The number of the atom is either less than one, larger than the current
number of atoms in the crystal or even larger than the maximum
number of atoms allowed in your implementation.
Check the value of the parameter(s) on the 'remove' and 'switch'
commands or check the index of the variables "m", "x", "y" or "z".
Check the number of atoms present in the crystal by the command:
'eval n[1]'.
Error : -20 : Unknown element, no Fourier calculated
An element was detected in the list of atoms for which there is no
scattering curve available. The Fourier transform is not calculated
at all. Check the name of all atoms present in the crystal using
the 'asym' and 'chem' commands. If a charged ion was given, this
valence might not be present in the list of scattering curves.
Refer to Appendix b of the manual for a list of internally stored
names.
If the 'scat' and/or 'delf' commands were used, any name may be used.
Check whether the commands were used properly.
Error : -21 : No element present, no Fourier calculated
There are no elements present at all in the crystal. The Fourier
transform is not calculated at all. Most likely, the Fourier
was called before a structure or unit cell was read, or an error
occurred during the reading of the structure or unit cell.
Error : -26 : Too many different atoms in crystal
The maximum number of different atoms allowed in your implementation
was exceeded. No more new types of atoms can be inserted into the
structure. Check the chemistry of your crystal by the 'asym' and
'chem' commands. All atoms are considered different types that are
chemically different, have different charge or a different temperature
coefficient. If all types are needed, modify the parameter "maxscat"
in the file "param.inc" and recompile the program. See chapter 9.1
of the manual for further information.
Error : -27 : No atom of this type present in crystal
An atom was selected for displacement by a wave or for plotting that
does not exist within the crystal. Check the spelling of the atom
name, and the chemistry of the crystal by the 'asym' and 'chem'
commands.
Error : -28 : Input parameters must be > zero
This function/command requires non-negative parameters.
Check the values of the parameters and the explanation for the function
or command used for valid ranges of numerical input.
Error : -32 : Length of vector is zero
An attempt was made to calculate the angle between two vectors
while one of them is of length zero. Check the parameters given
on the 'bang' or 'rang' command for proper numbers.
Error : -35 : Volume of unit cell <= zero
The volume of the unit cell was calculated as zero or a negative
value.
Check the lattice parameters given in the input file. Are there
any accidental "-" signs ? Do the angles form an impossible shape ?
Error : -37 : No filename defined yet
An attempt was made to write output to or read from a file without
defining a file name. PDFFIT does not provide default names for the
output of the 'plot' command or the input filenames. Check the
'outfile' command at sublevels 'output' and 'plot' or the 'content'
command at sublevel 'microdomains'.
Error : -43 : Not enough parameter for filename format
An attempt was made to generate a file name from a string like
"text%dtext" without supplying enough numerical parameters.
Check that the spelling of the sting within " " is correct. Are
there any unwanted %d combinations?. Check the number and type
of parameters following the file name.
Error : -44 : Right quotation mark missing in format
An attempt was made to generate a file name from a string like
"text%dtext" without supplying the right quotation mark.
Check the line and provide the missing ".
Error : -45 : Too many atoms in environment
The indices of all atoms found are stored in the internal variable
"res". More atoms were found that fit into the dimensions of "res".
Restrict the search for the environment to a smaller shell or
change the dimension of "res_para" in file "param.inc".
Error : -46 : Error reading title of structure
An error occurred while reading the title line of a structure or
unit cell file. Check the file for any garbage.
Error : -47 : Error reading space group symbol
An error occured while reading the space group line of a structure or
unit cell file. Check the file for any garbage.
Error : -48 : Error reading lattice constants
An error occured while reading the lattice constants of a structure
or unit cell file. Check the file for any garbage or accidental letters.
Error : -49 : Error reading atom coordinates
An error occured while reading the atom coordinates of the atom
listed. Check the file for any garbage. Is the line of the type
Name x y z B
Are there letters among the numerical values?
Error : -54 : Index outside limits
The value given is outside the proper limits allowed by this command. This usually means that an array element is outside the current dimension of an array, for example a correlation matrix or you are trying to include too many atoms in the crystal. Check the section on dimensions in the manual.
This category lists error messages that are specific PDF and refinement functions of PDFFIT.
Error : -1 : Invalid structure phase selected
The number of an invalid phase was given. One can only enter
phase specific commands when the corresponding structure was
actually read via 'read stru'.
Error : -2 : Number of phases outside limits
When trying to read another structural phase, the maximum number
of phases was exceeded. You might need to adjust the parameter
MAXPHA in 'config.inc' and recompile PDFFIT.
Error : -3 : Invalid occupancy specified
A site occupancy not in the range 0 to 1 was specified for an
atomic site. Check your input.
Error : -4 : Maximum number of data sets exceeded
When reading a PDF data set, the maximum number of data sets was
exceeded. You might need to adjust the parameter MAXDSET in the
file 'config.inc' and recompile PDFFIT.
Error : -5 : Invalid radiation type selected
The only radiation types allowed as parameter for the 'read data'
command are 'n' for neutrons and 'x' for X-rays. Check your input.
Error : -6 : Invalid data set specified
The number of an invalid data set was given. One can only enter
data set specific commands when the corresponding data file was
actually read via 'read data'.
Error : -7 : Invalid parameter constraint specified
The parameter constraint specified using 'par' is invalid. Either
it contains no "=" or tries to assign a non refinable variable to
a refinement parameter.
Error : -8 : Too many different parameters in constr.
You have entered a definition, that depends on too many different
refinement parameters. You might need to adjust the variable
MAXDPP in the file 'config.inc' and recompile PDFFIT.
Error : -9 : Inconsistency between NCELL and # atoms
When reading a structure file, the number of atoms actually found
does not match the number of atoms expected from the parameters
of the 'ncell' keyword. For 'ncell nx,ny,nz,n' you expect to read
nx.ny.nz.n atoms.
Error : -10 : Invalid parameter selected
An invalid refinement parameter was selected. Use the command
'show config' to see what the maximum number of refinement
parameters is you can use.
Error : -11 : Too many data points in experimental PDF
The PDF data file to be read contains too many data points. You
might need to adjust the parameter MAXDAT in the file 'config.inc'
and recompile PDFFIT.
Error : -12 : Cannot extend r-range for convolution
In order to calculate the PDF, the calculated function is convoluted
with a SINC function with a width determined by Qmax. In oder to
carry out the convolution a finite number of data points outside
the refinement range are needed. You have to use a lower RMAX for
the refinement or reprocess the PDF up to a higher R value.
Error : -13 : R-value out of range
You have specified a value of R that is outside the range for the
specified data set. Check your input.
Error : -14 : Parameter index in p[i] out of range
You have used a parameter index 'i' that is out of range. Note that the maximum allowed value of 'i' is determined by the maximum number of parameters that can be used for a given set of data and structural phases.