added prerequisites to README.txt

diff --git a/README.txt b/README.txt
index edf351f7a499cc96af6178482016be3aa6fa8d93..2ff284e776da625c5331b499b59ff5a7b9dd1ad5 100644 (file)
--- a/README.txt
+++ b/README.txt
@@ -1,6 +1,12 @@
 Strong simulation of multi-Pauli measurements using minimal stabilizer state decompositions
 -------------------------------------------------------------------------------------------
 
+PREREQUISITES:
+
+You will need the Lapacke library to run strongsim[1-12]_rellerr.c (in particular, the lapacke.h header).
+For instance, in Debian, you can obtain this by running:
+$ sudo apt install liblapacke-dev
+
 BUILD:
 
 1. We start with the code that scales quadratically with stabilizer rank because it calculates expectation values to zero relative error. Build code for stabilizer rank tensor multiple you'd like to use. Here we choose k=6.