Energy Versus Volume Fit Plugin

Energy Versus Volume Fit Plugin

The energy versus volume fit plugin calculates the non-linear fit of the Murnaghan Equation of State for a series of UR XML documents containing a sequence of total energy calculations for varying unit cell dimensions. Datasets are comprised of individual UR XML documents that have a definite unit cell volume and total energy. The fits of multiple datasets can be compared side-by-side on the same plot output. Also output is a table of the fit parameters including the equilibrium volume and bulk modulus.

Since not all electronic structure codes can compute the relaxation of a unit cell automatically, this plugin deals with pre-determined sequences of variable unit cell volume simulations each calculating the total energy.

Example: Silicon LDA Qbox vs Quantum Espresso

In this example we plot the fits of two data sets of uniformly distributed unit cell volume simulations of cardinality 11 each for Qbox and Quantum Espresso. The input looks like

	<uuids host="" proxy="8080">

In this case we have specified 22 UUIDs corresponding to UR XML documents and additionally stated that there are 2 datasets using the "<ndset>" element. This will direct the plugin to fit two curves: one based on each dataset of 11 documents. Each of these 11 documents are ordered such that the Qbox ones are listed first followed by the Quantum Espresso simulations, so the plugin simply bins to each set by counting the document index. The output of this transformation is

For more complicated datasets, you can also specify the size of each dataset that may be different from each other using the "<pdset>" element (instead of the "<ndset>" element) the value of which is a comma separated list of the dataset cardinalities, e.g. "<pdset>11,11</pdset>" in this case.