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PLOT

Function:

The PLOT command is used to obtain diagrams comparing the values of properties calculated using the LIST PROPERTY command with experimental data entered using the LIST VALUE command. Two types of diagram can be plotted, bar charts of ERRORs (differences between calculated and experimental results divided by corresponding experimental uncertainties entered using the LIST UNCERTAINTY command) or lines joining calculated VALUEs associated with the same abscissa variable (specified using the LIST ABSCISSA command) overlaid with symbols representing experimental data. The various LIST commands necessary to make PLOTs possible are usually provided in an EXPERIMENTAL_FILE (see DEFINE).

Parameters:

errors

values

Defaults:

All “experiments” (property and experimental data combinations) established using a LIST PROPERTY command are plotted, unless specific experiment numbers or labels, as appropriate, are given.

Examples:

plot errors experiment !

plot errors exp(1,2,10,11,13) !

plot values experiment(deltah) !

plot values exp(smith) !

Parameter values:


ERRORS

takes the value EXPERIMENT[(*)] where [ ] indicates an optional entry

The ERRORS parameter is used to generate a bar chart where each bar represents the difference between a calculated result accessed using LIST PROPERTY and an experimental value specified using LIST VALUE, divided by an experimental UNCERTAINTY entered using LIST UNCERTAINTY. Dividing by an UNCERTAINTY allows errors associated with different types of PROPERTY (mole fractions and Gibbs energies, for example) to be compared on a common basis. All or selected LIST PROPERTY values may be included.

The LIST commands associating an experimental VALUE, UNCERTAINTY and LABEL with each calculated PROPERTY  usually appear in an EXPERIMENTAL_FILE (see DEFINE).

EXPERIMENT(*)  is used to select results for inclusion in an ERRORS chart. This is done by appending a list of PROPERTY numbers or LABELs (see LIST PROPERTY) to the EXPERIMENT keyword, in brackets. If the EXPERIMENT keyword is entered without brackets, all available results are selected. For example:

plot errors experiment(1,3,5,10,12) !
plot errors exp !

Part of a LABEL can be entered to select results with different LABELs beginning with the same group of letters.

Typical output generated using plot errors experiment is shown on the next page.

VALUES

VALUES takes the value EXPERIMENT[(*)] where [ ] indicates an optional entry

The VALUES parameter is used to generate graphs in which calculated PROPERTY values accessed using LIST PROPERTY are plotted as ordinate and a variable specified using LIST ABSCISSA, common to each PROPERTY, is plotted as abscissa. Symbols representing experimental data, entering using LIST VALUE, with error bars based upon uncertainties specified using LIST UNCERTAINTY, are superimposed. All or selected LIST PROPERTY values may be included.

The LIST commands associating an experimental VALUE, UNCERTAINTY and an ABSCISSA variable with each calculated PROPERTY usually appear in an EXPERIMENTAL_FILE (see DEFINE).

EXPERIMENT(*)  is used to select results for inclusion in a plot. This is done by appending a list of PROPERTY numbers or LABELs (see LIST PROPERTY) to the EXPERIMENT keyword, in brackets. The same ABSCISSA variable should be associated with each selected PROPERTY (see LIST ABSCISSA). If the EXPERIMENT keyword is entered without brackets, all available results are selected. For example:    

plot values experiment(1,3,5,10,12) !
plot values exp !

Part of a LABEL can be entered to select results with different LABELs beginning with the same group of letters.

Typical output generated using plot values experiment is shown on the next page.

 

Updated 4 August 2010