+ if (isinf (f) || isnan (f) || f < 0)
+ programming_error ("insane spring constant");
+ else
+ inverse_compress_strength_ = f;
+
+ update_blocking_force ();
+}
+
+void
+Spring::set_blocking_force (Real f)
+{
+ if (isinf (f) || isnan (f))
+ {
+ programming_error ("insane blocking force");
+ return;
+ }
+
+ blocking_force_ = -infinity_f;
+ min_distance_ = length (f);
+ distance_ = max (distance_, min_distance_);
+ update_blocking_force ();