Added note on design goals

docs/src/index.md

@@ -9,6 +9,25 @@ provides fully static multivectors (Clifford numbers) in arbitrary dimensions an
 in many cases, sparse representations of multivectors are more efficient, for spaces of low
 dimension, dense static representations may provide a performance and convenience advantage.
 
+## Design goals
+
+The goal of this package is to provide a multivector implementation that:
+  * Allows for the construction of multivectors in arbitrary metrics, with coefficients that subtype
+any instance of `Real` or `Complex`.
+  * Provides data structures of fixed sizes that represent multivectors. This allows for instances
+to be allocated on the stack or stored inline in an `Array` rather than as pointers to individually
+allocated instances.
+  * Provides dense representations of multivectors, as well as convenient sparse representations,
+which can be constructed from each other, converted in a way that guarantees representability, and
+allows for promotion between instances.
+  * Subtypes `Number`: The term "Clifford number" emphasizes the perspective of multivectors as an
+extension of the real numbers, in the same way that complex numbers and quaternions extend them.
+(It should be noted that both complex numbers and quaternions are Clifford algebras!)
+  * Aggressively optimizes all mathematical operations, utilizing `fma` operations and SIMD
+instructions whenever possible.
+  * Interoperates with automatic differentiation tools and other packages which allow for the
+implementation of operations from geometric calculus.
+
 ```@index
 ```