 distance - computes the distance between two points.

 diff_sq_distance - computes the squared distance between two points.

 perp_dist - given a point in space and the slope and a point on a line,
             computes the perpendicular distance from the first point to
             the line.
 compute_slope - computes the slope of the line between two points.

 compute_y - given the x coordinate, slope, and another point on the
             line, computes the corresponding y coordinate.
 applyparam3_to_point - takes an x and y coordinate pair and applies
                        the specified Least Squares parameters with
                        three degrees of freedom.
 chkfindparam3 - finds the best fit between two corresponding sets of
                 points while checking for errors in the location of
                 the hypothesized points.
 findparam3 - finds the best fit between two corresponding sets of
              points using Least Squares with 3 degrees of freedom.
 determinant3 - computes the determinant for Least Squares with 3
                degrees of freedom.
 scale1param3 - computes the first scale parameter for Least Squares
                with 3 degrees of freedom.
 scale1param3 - computes the second scale parameter for Least Squares
                with 3 degrees of freedom.
 deltaparam3 - computes the translation parameter for Least Squares
                with 3 degrees of freedom.
 lsq_ind_line_params - given a list of indirectly addressed datapoints,
                       computes the slope and y-intercept using Least
                       Squares.
 lsq_line_params - given a list of datapoints, computes the slope
                   and y-intercept using Least Squares.
 determinant2 - computes the determinant given accumulated x and x*x
                and the number of datapoints.
 scaleparam - computes the scale parameter for Least Squares with 2
              degrees of freedom.
 deltaparam - computes the translation parameter for Least Squares
              with 2 degrees of freedom.
 compute_mean - takes a list of integers and computes the mean.

 within_mean_slope - heuristic used in constreader, tests both a
                     distance within a factor of the given mean and
                     a slope within a given tolerance.
 sumints - computes the summation of the given integer list, sum(x).

 sumprodints - computes the summation of two integer lists pointwise
               multiplied, sum(x*y).
