Update README

README.md

@@ -1,14 +1,50 @@
 # Autopen
 
-(As in [the device](https://en.wikipedia.org/wiki/Autopen), and a [pen](https://en.wikipedia.org/wiki/Pen_%28enclosure%29) for [assorted](https://en.wikipedia.org/wiki/LLaMA) [macrofauna](https://lmsys.org/blog/2023-03-30-vicuna/))
+A text editor that lets you view the text through the eyes of an LLM, see what it expects and what it finds surprising, generate continuations,
+and seamlessly explore different alternatives at every point - as in [the device](https://en.wikipedia.org/wiki/Autopen), and a [pen](https://en.wikipedia.org/wiki/Pen_%28enclosure%29) for [assorted](https://en.wikipedia.org/wiki/LLaMA) [macrofauna](https://lmsys.org/blog/2023-03-30-vicuna/).
+
+![Screenshot](/screenshots/screenshot.png?raw=true)
+
+LLMs are essentially functions that produce, given any piece of text, a probability distribution over words and word fragments that may immediately follow it.
+This true nature is hidden by the way in which LLMs are usually deployed: the LLM is applied to an input string to obtain a distribution, the distribution is *sampled* in some way to pick a single word or fragment to attach, and the resulting extended string is fed back as an input, over and over again. Thus, the LLM becomes a device that produces a single possibly endless stream of text, which (depending on the sampling procedure) may be nondeterministic.
+
+The abstraction of LLMs into "writing machines" is certainly compelling, and has by now given rise to endless forms most beautiful of applications. Used in this way,
+the model becomes a slightly unruly building block without regard to the probabilities of each choice that is made or the possibilities that the sampler discards. However, to really understand how a given model ticks, how its "thought patterns" emerge and what gives rise to its mistakes and idiosyncrasies, we need a way to look at that data.
+
+Autopen was created for that purpose. It can:
+
+* Edit text.
+
+* Load and execute any LLM in the GGUF format that [llama.cpp](https://github.com/ggerganov/llama.cpp) can run.
+
+* Highlight the text in real time to visualise which tokens are "surprising" to the model (have low probability).
+
+* Generate and simultaneously display multiple continuations at each point in the text, ordered by descending probability according to the LLM.
+
+* Flip through these continuations (Alt-⬆⬇) and emit them into the buffer (Alt-⮕). 
 
 [![Demonstration video](https://img.youtube.com/vi/1O1T2q2t7i4/maxresdefault.jpg)](https://www.youtube.com/watch?v=1O1T2q2t7i4)
 
+This project is powered by [llama.cpp](https://github.com/ggerganov/llama.cpp), [dear imgui](https://github.com/ocornut/imgui) and [imgui-filebrowser](https://github.com/AirGuanZ/imgui-filebrowser/), as well as SDL2 and OpenGL.
+
+The code that is original to this project is licensed under the GNU GPL v3.
+
+### Known limitations
+
 This is not release-quality software. Expect crashes, unexpected behaviour and terrible code.
 
-Everything is licensed under the GNU GPL version 3. At this stage, I don't intend to accept pull requests.
+* Currently, models with SPM tokenization (such as Phi-3.5) are broken. This can be worked around with with a simple patch to llama.cpp, but that is a bit of a deployment nightmare.
+
+* Crashes due to out-of-memory conditions and bugs are not handled gracefully.
+
+* Save/load function for the buffer is a TODO. Copypaste to/from the text editor of your choice.
+
+* Due to imgui's rendering model, there is nontrivial idle CPU usage (which grows with your monitor's framerate). A smart throttling scheme would be useful.
 
 ### To build
+Currently a mess.
+
+On Linux (possibly outdated):
 ```
 git clone https://github.com/ocornut/imgui.git
 cd imgui
@@ -23,6 +59,9 @@ cmake .
 make
 ```
 Dependencies may include SDL2 and more.
+
+On Windows: try the VS2022 .sln file (and vcpkg). imgui should be cloned as on Linux, and llama.cpp should be cloned and built with a configuration matching the Release/Debug setting you pick (as libcommon has to be statically linked). Some adjustment of include and library directories will probably be necessary.
+
 ### To run
 ```
 ./cmake-build-Release/output/autopen