choclo.prism.kernel_nnu

choclo.prism.kernel_nnu(easting, northing, upward, radius)

Northing-northing-upward kernel due to a prism.

Evaluates the integration kernel for the northing-northing-upward component of the grad tensor generated by a prism [Nagy2000] on a single vertex of the prism. The coordinates that must be passed are shifted coordinates: the coordinates of the vertex from a Cartesian coordinate system whose origin is located in the observation point.

Parameters:

easting, northing, upwardfloat

Shifted easting, northing and upward coordinates of the vertex of the prism. Must be in meters.

radiusfloat

Square root of the sum of the squares of the easting, northing and upward shifted coordinates.

Returns:

kernelfloat

Value of the kernel function for the northing-northing-upward component of the grad tensor due to a rectangular prism evaluated on a single vertex. Return np.nan if radius is zero (i.e. observation point is on the vertex).

Notes

Computes the following numerical kernel on the passed shifted coordinates:

\[k_{yyz}(x, y, z) = \frac{ - y }{ (x + \sqrt{x^2 + y^2 + z^2}) \sqrt{x^2 + y^2 + z^2} }\]

Examples

>>> x, y, z = 3.1, 5.2, -3.0
>>> r = np.sqrt(x**2 + y**2 + z**2)
>>> float(kernel_nnu(x, y, z, r)) 
-0.07808384