Low level Haskell bindings to the [C levmar (Levenberg-Marquardt)
library](http://www.ics.forth.gr/~lourakis/levmar/)

See the [levmar](http://hackage.haskell.org/package/levmar) package
for a high-level wrapper around this package.

The Levenberg-Marquardt algorithm is an iterative technique that finds
a local minimum of a function that is expressed as the sum of squares
of nonlinear functions. It has become a standard technique for
nonlinear least-squares problems and can be thought of as a
combination of steepest descent and the Gauss-Newton method. When the
current solution is far from the correct one, the algorithm behaves
like a steepest descent method: slow, but guaranteed to converge. When
the current solution is close to the correct solution, it becomes a
Gauss-Newton method.

Both unconstrained and constrained (under linear equations and box
constraints) Levenberg-Marquardt variants are included.  All functions
have `Double` and `Float` variants.

Note that the included C library is lightly patched to make it
pure. This way the functions can be used inside `unsafePerformIO`.

License
=======

All files **except** those in the `levmar-2.4` directory fall under
the BSD3 license. The levmar C library, which is bundled with this
binding, falls under the GPL. If you build a program which is linked
with this binding then it is also linked with levmar. This means such
a program can only by distributed under the terms of the GPL.