Updating readme

Signed-off-by: B Horn <b@horn.uk>

README.md

@@ -3,4 +3,40 @@
 
 ## Project Structure
 
+We have four components:
 
+### Examples
+
+Our Example code, which was used to validate the work.
+
+### Simulation
+
+Utils for simulation, one is for getting a random distribution and the other is
+a step helper to wrap a normal step function with the gloss viewport.
+
+### Visualization
+
+Helper functions for generating Gloss UIs showing off various data structures.
+
+### VRC
+
+The core of the project, this is where the variable rate logic is implemented.
+
+* `Types.hs` - Type definitions
+* `Pipeline.hs` - Pipeline based variable rate workloads. What you should ideally
+  be using.
+* `RegionOperators.hs` - Operations like Map/Stencil that work on regions.
+* `Primitives.hs` - Ideally, this is what would be provided by the core
+  accelerate language to make this easier to build.
+* `Utils.hs` - Helper functions 
+
+## Limitations
+
+This is a prototype and doesn't really preform that well. We have to `run` in
+one annoying place, but that should be fixable.
+
+Our examples being simulations need us cache the results of the computation
+every step. Real work could skip this and just get the final result.
+
+Also, the code just runs on the CPU due to CUDA versions (I have 11.2 installed
+due to running 460 series drivers, but Accelerate only supports CUDA 10)