+ Real den = (count * sqx - sqr (sx));
+ if (!count || !den)
+ {
+ programming_error ("minimise_least_squares (): Nothing to minimise\n"
+ "This means that vertical spacing is triggered\n"
+ "before line breaking\n");
+ *coef = 0.0;
+ *offset = count ? sy / count : 0.0;
+ }
+ else
+ {
+ *coef = (count * sxy - sx * sy) / den;
+ *offset = (sy - (*coef) * sx) / count;
+ }