Partial roll-back of ELPA_2015.02.001 release

We found a bug in the QR-decomposition, which appears for
some matrix sizes and produces wrong results!

If the QR decomposition is switched on, an appropiate warning
is shown.

This bug is still under investigation

RELEASE_NOTES

@@ -16,7 +16,8 @@ The only major change (which results in point a) is in the ELPA-2
 part of the library for real matrices:
 
 the fully blocked QR decomposition has been moved from the development part
-to the release!
+to the release! However, this is still experimental, since there is still
+a bug. For some matrix sizes the results are wrong
 
 It is now possible to use this QR decomposition by either setting an
 environment variable "ELPA_QR_DECOMPOSITION" to "yes", or to call the
@@ -36,6 +37,10 @@ c)
 The configure procedure was adapted to be more consistent. No compiler omptimization
 flags are set automatically anymore, this is up to the user at build time
 
+d)
+
+The checks for OpenMP in the configure have been improved
+
 Any incompatibles to previous version?
 ---------------------------------------
 

src/elpa2.F90

@@ -646,6 +646,11 @@ function solve_evp_real_2stage(na, nev, a, lda, ev, q, ldq, nblk,        &
      useQRActual = useQREnvironment
    endif
 
+   if (useQRActual) then
+     print *,"Carefull you use the experimental feature QR-decomposition"
+     print *,"it is possible that the results are wrong"
+   endif
+
    if (present(THIS_REAL_ELPA_KERNEL_API)) then
      ! user defined kernel via the optional argument in the API call
      THIS_REAL_ELPA_KERNEL = THIS_REAL_ELPA_KERNEL_API