BUG: `calculate_distance_matrix` does not compute all distance pairs.

[bifbof]

In calculate_distance_matrix we can either compare an X to itself or to another Y. The code does some optimization for X in assuming that the computation is symmetric and only doing half of the pairs (e.g. (x[0], x[1]) has the same result as (x[1], x[0])). But the same thing is done if a Y is provided, here (x[0], y[1]) can be different to (x[1], y[0]). This code triggers the bug:

import geopandas as gpd
import trackintel as ti
from shapely.geometry import Point
a = [(0, Point(0, 0)), (1, Point(1, 1))]
b = [(0, Point(10, 10)), (1, Point(20, 20))]
a = gpd.GeoDataFrame(a, columns=["id", "g"], geometry="g")
b = gpd.GeoDataFrame(b, columns=["id", "g"], geometry="g")
res = ti.geogr.calculate_distance_matrix(a, b)
assert res[0,0] != 0

Further the whole implementation is full of bugs and smaller issues, things I found at a quick glance:

• the n_job default value is non-valid value 0
• this assert compares a variable to itself
• this assignment makes no sense with non-symmetric matrices
• this else branch is unreachable, because we set Y to not None here
• this line forgets to pass kwds
• this is a ValueError and not an AttributeError
• The docstring is confusing in multiple places

Further the test suite for this function is not useful. All except one test only compare the output of the function to different output of the function or to nothing at all. The one exception does not provide a Y.