two body skateboard 1st commit

README.rst

@@ -38,6 +38,19 @@ form, primarily the formation of the constraints and the Jacobian of the
 constraints, manually is a time consuming and error prone process. ``opty``
 eliminates both of those issues.
 
+opty uses its primary dependencies in the following ways:
+
+- SymPy: Symbolically discretizes the DAEs, analytically computes all necessary
+  derivatives, and generates C code to efficiently evaluate the DAEs and their
+  associated derivatives.
+- Cython + NumPy: Just-In-Time compiles the C code generated by SymPy and
+  wraps it for use with NumPy arrays.
+- cyipopt: Wraps the Ipopt C API and provides a generic NLP problem definition
+  class which opty's problem class is derived from to facilitate input and
+  output from Ipopt as NumPy arrays.
+- Ipopt: Consumes the numerical problem definition passed via cyipopt and then
+  solves it using an interior point method.
+
 .. _SymPy: http://www.sympy.org
 
 Features