class PDensityMatrix: public PEmbeddedParticles

checks if there is a grid border between bin-1 and bin

Reads a density matrix which must be organized in one of the the two following way

Method 1:
x [y] [z] f1 f2 f3 ....

The first column contains the bin center on the x-axis, the following
columns the values of 1 or more matrices. Optionally, for 2- and 3-dimensional
matrixes, the first colum might be followed by the y- and z-value of the bin center

The matrixes support variable bin width, the flag "use_bin_width" should be used
to select of the sample statistics should be corrected by the bin width

Method 2:
"section value 1"
x [y] [z] f0 f1 f2 ....

"section value 2"
x [y] [z] f0 f1 f2 ....


Here, the syntax is like in method 1, but if lines have only one number,
they are considered to be a "selection number". Which of the sections should be read
and used to fill the internal matrix, can be selected by "min_selection" and "max_selection"
The section is used if "min_selection" <= "section value" <= "max_selection"

In your macro, to select one of the matrixes, use
  matrix->SetMatrix(N);
where N corresponds to fN, e.g.
  matrix->SetMatrix(2);
uses the values f2 as defined above

 Read the particles from the defined stack and copy this to the official
 particle stream