Fit the input hard sphere Yukawa colloid I(Q) curve.
**Usage**
Initial guess, lower bound and upper bound are separated using spaces.
Q points are rescaled such that QD in 0.2:0.2:16, the sigma fitting parameter reflects the differences between the actual particle radius and the initial guesses.
**Acknowledgement**
This research was sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U. S. Department of Energy.
