Density Profile
===============

The density profile node shows the number density for each atom type.
You can choose which axis to calculate the density.

.. image:: img/dens.png
    :width: 90%
    :align: center

The ``count`` parameter controls how many slices to calculate the density profile.
Larger values gives a more detailed graph, but with more noise.

The density of each type has a different index in the 2nd axis,
so the density profile for a single type can be specified with the ``Y axis index`` of the Plotter.

The graph setup is as follows.

.. image:: img/denscon.png
    :width: 50%
    :align: center

.. highlight:: cpp

Source code (Error checking omitted)::

    #include <iostream>
    #include <cmath>
    #include <vector>
    #include <unordered_map>

    //@in 6
    double* bbox = 0;
    //@in enum X Y Z
    int axis = 0;
    //@in
    int count = 0;
    //@in parcnt 3
    double* positions = 0;
    //@in parcnt
    short* types = 0;

    //@out count typecnt
    double* density = 0;

    //@var
    int parcnt = 0;
    //@var
    int typecnt = 0;

    //@entry
    void Do () {
        double zmin = bbox[axis*2];
        double zmax = bbox[axis*2+1];
        double vol = (bbox[1]-bbox[0])*(bbox[3]-bbox[2])*(bbox[5]-bbox[4]) / count;
        double dd = 1/vol;
        std::unordered_map<short, std::vector<double>> dens;
        for (int a = 0; a < parcnt; a++) {
            auto z = (positions[a*3 + axis] - zmin)/(zmax-zmin);
            auto i = (int)floor(z*count);
            if (i < count) {
                short tp = types[a];
                dens[tp].resize(count);
                dens[tp][i] += dd;
            }
        }
        typecnt = (int)dens.size();
        if (density) delete[](density);
        density = new double[count * typecnt];
        int a = 0;
        for (auto& d : dens) {
            for (int x = 0; x < count; x++)
                density[x*typecnt + a] = d.second[x];
            a++;
        }
    }

.. raw:: latex

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