Allows the user to define the system to be
studied: in one mode, the
data are retrieved from specified databases; in the alternative mode
the data are read from a previously created file. When a database
search has been performed the data for the system under study are
written to a user-defined or system default file.
<first database on the database menu>
data = "project4" !
system = "Cu, S, /-, O, H" source = aqe aqd !
data = default !
system = "Al, H, Cl, O" output 'myalhclo' !
If the DEFINE
statement contains a reference to a
DATA_INPUT_FILE the program reads the required data from the specified
datafile. Such a datafile could have been created in a previous
run of COPLOT, MULTIPHASE or ACCESS.
If DATA = DEFAULT is used, then the data are read from the last
datafile generated with the default name, usually "def.mpi".
takes the value
specifies file to which the data resulting from the database search are to be
sent. The output file is specified in the same DEFINE statement as that of the SYSTEM
specification. If no output file root is defined then the data are written to
a system default file, typically "def.mpi" in the current directory.
OUTPUT_DATA/RESULTS does not change the name of the file that contains the results of COPLOT calculations, which is always called COPOUT.DAT and is overwritten by each new calculations.
takes the value <"component
The SYSTEM parameter
is used to define the components
of the system to be studied prior to the search of one or more
databases. Components may be elements, compounds or charged species.
For COPLOT a charged species must appear other than last in the list if
the system is to be 'open' to charge.
define system = "Cu,S,/-,H,O" !
define system = "Cu,S,H2O,H/+,O" !
will retrieve the same set of substances. Never include more than one charged somponent in the component list.
DEFINE SYSTEM is executive causing
the program to search the list
of databases specified by use of the SOURCE parameter, for the
substances that are linear combinations of the components DEFINEd.
These are written to a datafile based upon the OUTPUT_DATA/RESULTS
file root and then loaded into memory.
takes the values ALL/ <database
list>/ <"database path">/NONE_BUT<database
This defines the
databases to be searched in the
specified order. It is recommended that the SYSTEM and SOURCE
parameters are set within the same DEFINE statement. If the SOURCE
parameter is assigned a value before a DEFINE SYSTEM command is
issued the default data input file is also loaded. If a value
for the SOURCE parameter is not specified the first database in
the database menu is searched when the SYSTEM is defined. If aqueous
water or the aqueous electron is required in the system, it may be
necessary to include the AQEXTRAS database in the list.
a user-defined list
consisting of any of the databases
appearing in the database menu.
the path of a database
not on the database list.
ALL this specifies the complete
list of databases in the order in which they appear in the database
clears any previous
list and defines a new one.
When the DEFINE SYSTEM
command is executed, the databases
specified by use of the SOURCE parameter are searched in the specified
order for all the substances that are linear combinations of the
components defined by the SYSTEM. For a large number of components,
the number of substances retrieved may easily run to tens, if
not hundreds, of species. COPLOT is configured
with at least 200 substances, the actual limits depending on the
type of computer being used. The limits for a particular version
of MTDATA can be inspected by using the LIMITS
of the UTILITY module. If the number of substances
than can be supported by the COPLOT module it
practice to use the ACCESS module to perform a
screening of species, and write a reduced substance list to a
file. This may then be read by the COPLOT module using
the DEFINE DATA command.
A relationship exists
between ACCESS and COPLOT in terms of the datafiles that are generated. The purpose of using ACCESS
is to perform a preliminary
review of the data and
to enable phases and/or substances to be excluded from the MULTIPHASE
input data file created so that it is suitable, in size and form,
for use by COPLOT and other MTDATA
The recommended method for terminating an ACCESS
is to define the name of a file to which the edited data may be
SAVEd and then to issue the SAVE command. At a later date the
file may subsequently be read by the DEFINE DATA statement in COPLOT.
If such a filename has not
been defined within
the ACCESS module when the SAVE command is issued,
data are SAVEd to a default file. These data can be retrieved
in COPLOT by the command:
This procedure is to
be recommended only if the ACCESS
and COPLOT modules are used subsequently within
same session of MTDATA. Otherwise, the default
is in danger of being overwritten.