From 620ea1aa3ac4c148e89f5db62d32b40004e4f819 Mon Sep 17 00:00:00 2001
From: Paolo Giannozzi <p.giannozzi@gmail.com>
Date: Fri, 21 Feb 2020 15:27:02 +0000
Subject: [PATCH] Additional info on AMD libraries

---
 Doc/user_guide.tex | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/Doc/user_guide.tex b/Doc/user_guide.tex
index 6a2465680..3b9ca3345 100644
--- a/Doc/user_guide.tex
+++ b/Doc/user_guide.tex
@@ -1130,8 +1130,14 @@ is that I also saw some strange numbers when using libflame/aocl 2.1.
 export MKL_DEBUG_CPU_TYPE=5
 \end{verbatim}
 which gives an additional 10-20\% speedup with MKL 2020,
-while for earlier versions the speedup is greater than 200\%.''
-(Info by Tobias Kl\"offel, Feb. 2020)
+while for earlier versions the speedup is greater than 200\%.
+[...] Another note, there seem to be problems using FFTW interface
+of MKL with  AMD cpus. To get around this problem, one has to
+additionally set
+\begin{verbatim}
+export MKL_CBWR=AUTO
+\end{verbatim}
+`` (Info by Tobias Kl\"offel, Feb. 2020)
 
 \subsubsection{Linux PC clusters with MPI}
 \label{SubSec:LinuxPCMPI}