add AbstractArray compatability to readme

Author: JaredCrean2

README.md

@@ -53,6 +53,16 @@ Currently, most of the Vector Beginner and Intermediate functions are implimente
   * For each Petsc object, you must create a type that holds a void pointer called pobj and use that in place of the (incorrect) type generated by Clang.jl
   * For every function you add, create a test
 
+## Compatability with AbstractArray
+A limited vocabulary of functions are provided that can operate on Petsc vectors
+and matrices as well as AbstractArrays.  They are:
+
+`set_values1!`
+`get_values1!`
+`PetscMatAssemblyBegin`
+`PetscMatAssemblyEnd`
+
+
 ## Directory Structure
   `/src` : source files.  PETSc.jl is the main file containing initialization, with the functions for each type of Petsc object in its own file.  All constants are declared in `petsc_constants.jl`.