Purpose: Given the parameters of two ellipses, this function calculates
the area of overlap between the two curves. If the ellipses are
disjoint, this function returns 0.0; if one ellipse is contained
within the other, this function returns the area of the enclosed
ellipse; if the ellipses intersect, this function returns the
calculated area of overlap.
More details are inside the paper.
The program is coded in C and is published under the GNU-License.
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