Users.Graphics.Plots

About plots generated by the Matlab/Octave version of WavePacket

The Matlab/Octave version of WavePacket comes with sophisticated visualization, typically generated "on the fly", i. e. while a numerical simulation (qm_bound, qm_propa) or our movie generator (qm_movie) is running.

There is a plethora of settings for the plot layout, all of which can be optionally overwritten in your initialization file qm_init.m, see also our description of variable "plots". However, for a beginner we recommend to simply use the default settings. It is also recommended that you look at the demo examples in the WavePacket central Wiki. Of particular importance is the choice of the plot type in these files, e.g., for the densities to be visualized as a contour plot, you have to create an object of type contour

plots.density = vis.contour;

in your initialization file qm_init.m. Note that the respective class definition is found in package folder +vis inside the folder Sources. Various optional settings can be realized by assigning the class properties some desired values, e.g.

plots.density.energy = true;
plots.density.expect = true;

which specifies both the (potential and/or kinetic) energy as well as (position and/or momentum) expectation values to be drawn in addition to the contour representation of the densities.

For a complete list of other plot types, see the following list:

In 1 dimension

class	description	example
curve	Curve plots in position (DVR) or in momentum (FBR) representation	see here
polar	Polar plots ("quantum flowers")	see here
contour	Contour plots of Wigner representations	see here or here
surface	Surface plots of Wigner representations	see here
flux	Stem plots of probability fluxes	see ???
scatter	Scatter plots (trajectories "traj" only)	see ???
bar	Bar graph (state vectors "ket" only)	see here

In 2 dimensions

class	description	example
contour	Contour plots in position (DVR) or in momentum (FBR) representation	see ???
surface	Surface plots in position (DVR) or in momentum (FBR) representation	see here
flux	Quiver plots of probability fluxes	see ???
bar	Bar graph (density matrices "rho" only)	see here

In 3 dimensions

class	description	example
surface	Iso-surfaces in position (DVR) or in momentum (FBR) representation	see here

In any number of dimensions

class	description	example
reduced_1d	Reduced densities in each dimension	see here
reduced_2d	Reduced densities in pairs of dimension	see ???

Plots of expectation values

In addition to the animated plots of the density evolution, the Matlab/Octave version of WavePacket also creates plots of expectation values, also 'on the fly'. For this to happen, you will have to issue the following command

plots.expect = vis.expect;

This serves to create an object of class expect. For more details, also on the various settings/properties thereof, see here

Plots of spectra

In addition to the plots of the evolution of densities and expectation values, the Matlab/Octave version of WavePacket can optionally create plots of absorption spectra, calculated as Fourier transforms of temporal autocorrelation functions. Only available for propagations of wavefunctions!

In order do this and also to export these plots as files (default file names: wave_spectrum.jpg, wave_spectrum.fig), you will have to issue the following commands

plots.spectrum        = vis.spectrum;
plots.spectrum.export = true;

This serves to create an object of class spectrum. For more details, also on the various settings/properties thereof, see here

[Burkhard Schmidt]

Should soon be rewritten using function handles