MTDATA – Phase Diagram Software from the National Physical Laboratory

 

 

 

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PLOT

Function:

allows the user to plot graphs based on information stored in an existing graphics results file. Facilities within this command allow the graphics file to be selected, a directory of graphics results files (ie those with the extension ".GPH") to be obtained, the title and size of the plot and the way chemical formulae are printed to be changed, annotation (key) to the plot to be removed, the listing of the settings (constraints) in terms of moles and mass plot to be interchanged and output to be directed to the screen, a file or both. Use of this command also allows the user to obtain results in tabular form and to superimpose experimental data on graphs. See also ORDINATE, ABSCISSA and LASER.

Parameters:

directory

title_of_plot

key output

frame_size

constraints

tabulate

experimental_file

Defaults:

filename = <name of current graphics resultsfile>

title_of_plot = <name and date of graphics results file>

output = screen_and_file

constraints = as set up by user in calculation

tabulate = no_table

experimental_file = none

Examples:

plot filename = "project27" !

plot key = subscript !

plot output = file_only !

plot frame_size = reduced !

plot constraint = mass !

plot go


Parameter values:

FILE

takes the value <"filename">.

The default file is the last graphics results file calculated in the current session of MULTIPHASE. This file is automatically loaded if the command PLOT is followed by any other parameter than FILE or DIRECTORY. Otherwise the named file must have been previously calculated and in the current directory. The filename must be in quotes and does not need to include the file extension (which is ".GPH"). To obtain a list of GPH files use the parameter DIRECTORY.

DIRECTORY

does not require a value and should be followed by <CR>. A listing of graphics results files in the current directory, ie those with the extension ".GPH", is obtained.

TITLE_OF_PLOT

takes the value <"title"> or DEFAULT.

The default title is the root name of the graphics results file just calculated followed by a sequential number plus the date and time of calculation. The limit in size of a user defined title is 80 characters.

KEY

takes the values NO_KEY_NO_LABELS/NO_KEY_BUT_LABELS/CHARACTER_LABELS/SUBSCRIPT_MODE/DEFAULT

This refers to a KEY which is printed by DEFAULT to the right of all graphs formed by more than one curve. It matches the numbers used to label each curve to a list of the phases, substances or components considered in the graph's calculation. Single numbers may be used to refer to groups of curves if they overlap or are packed closely together. The element stoichiometry numbers in the phase, substance or component names can be subscripted by selecting SUBSCRIPT_MODE. The construction of the key can be suppressed altogether, along with the labelling of curves, by selecting the NO_KEY_NO_LABELS option. To suppress the key but leave the curve labels intact the NO_KEY_BUT_LABELS option can be used. In this latter case to make sense of the labels a previous graph with a key and a similar choice of ordinate would have to be consulted. Selecting CHARACTER_LABELS causes curves to be labelled with the appropriate phase, substance or component names rather than numbers. The construction of the key is also suppressed. Names tend to be much longer than numbers so more free space is needed on each plot for character labelling than for numeric labelling. Hence this option is not recommended for plots with many lines spaced closely together. In such cases numeric labelling is much more efficient. See also CONSTRAINTS.

OUTPUT

takes the values SCREEN_ONLY/FILE_ONLY/SCREEN_AND_FILE

Output can be directed to the screen or a plotfile or to both by selecting from SCREEN_ONLY, FILE_ONLY or SCREEN_AND_FILE, which is the default.

FRAME_SIZE

takes the values DEFAULT/REDUCED

The user can select the DEFAULT or REDUCED frame size. REDUCED is 70% of the linear dimension of the DEFAULT size and gives a relatively greater line thickness, which may be more suitable for use in slides, publications or reports.

CONSTRAINTS

takes the values MOLES/MASS

The settings imposed by the user (overall quantities of each component, temperature, pressure etc) are printed to the right of each graph, below the key if one appears. Amounts of components are given in moles if originally entered by the user in moles, or as masses if entered as masses. Occasionally it may be useful to switch between the two. This is done by selecting, as appropriate, "CONSTRAINTS=MOLES" or "CONSTRAINTS=MASS".

EXPERIMENTAL_FILE

takes the value <"filename">

This is used to superimpose experimental data from a file, stored in an MTDATA metafile format (see UTILITY handbook) on MULTIPHASE plots.

TABULATE

takes the values SEQUENTIAL/MULTIPLE_COLUMN/SPREADSHEET/NO_TABLE

This parameter is used to generate a table of abscissa and ordinate values instead of the graphical output produced by GO. By default the tabular output takes the form of a SEQUENTIAL list of abscissa/ordinate pairs for each different ordinate variable. Alternatively a single table with MULTIPLE_COLUMNS, one for each different ordinate variable, or a table designed for reading into a SPREADSHEET may be selected. The table is sent to a file with the extension ".GTB". For example

plot tab multiple_columns !

Plot tab no_table !

The maximum number of characters per line available for MULTIPLE_COLUMN output in ".GTB" files can be adjusted by setting the MTDATA environment variable MAX_CHAR as follows:

[MAX_CHAR=80

The DEFAULT setting is 132.

GO

the entry of GO and <CR> begins the plot. No exclamation mark should be entered. An extra <CR> is necessary to clear the screen.


 

Updated 7 May 2010