********>Bugfix 2:
Author: Ray Luo
Date: 05/2/2006

Programs: pbsa, sander

Description: sa_driver.f has a statement causing a negative number to be
             taken square root. This is not correct, but many compilers
             allow it.

Fix:  apply the following patch to amber9/src/pbsa/sa_driver.f, and to
      amber9/src/sander/sa_driver.f

------------------------------------------------------------------------------
*** sa_driver.f	Mon Apr  3 23:35:48 2006
--- sa_driver.f	Tue May  2 12:05:09 2006
***************
*** 991,997 ****
           dyij = acrd(2,jatm) - yi
           dzij = acrd(3,jatm) - zi
           d2 = dxij**2 + dyij**2 + dzij**2
!          if ( d2 >= (ri + rj)**2 ) cycle
            
           ! setting up indexes ...
            
--- 991,997 ----
           dyij = acrd(2,jatm) - yi
           dzij = acrd(3,jatm) - zi
           d2 = dxij**2 + dyij**2 + dzij**2
!          if ( d2 >= (ri + rj)**2 .or. d2 <= (ri - rj)**2 ) cycle
            
           ! setting up indexes ...
            
------------------------------------------------------------------------------

Temporary workarounds: none