********> bugfix.11
Author:   James Caldwell
Date:     4/25/95, amended 5/29/95 by Petr Mejzlik, changing 'atwork' to 'awork'
                   (distributed source was correct)

Programs: resp

Severity: moderate

Problem:  Lapack routine detects singular matrix

Affects:  multiple molecule fits

Cause:    elements on matrix diagonal are 0
          An earlier implementation using Numerical Recipes routines
          set these elements to 'very small'; this was lost in converting
          to Lapack.

Fix:  Make the following change to resp.f
------------------------------------------------------------------------
*** OLD resp.f
--- NEW resp.f
***************
*** 2407,2412
  c
  c  the solution "x" is returned in "b" (bwork)
  c
        call DGETRF( NATPL1,NATPL1,awork,maxq,iscr1,istat)
        if(istat.lt. 0) then
          write(6,'('' chgopt: LU decomp has an illegal value'')')

--- 2407,2419 -----
  c
  c  the solution "x" is returned in "b" (bwork)
  c
+ c     -- condition the matrix diagonal to avoid DGETRF() detecting
+ c        singularity
+ c
+       do jn = 1,natpl1
+         if (abs(awork(jn,jn)).lt. 1.d-10) awork(jn,jn) = 1.d-10
+       enddo
+ c
        call DGETRF( NATPL1,NATPL1,awork,maxq,iscr1,istat)
        if(istat.lt. 0) then
          write(6,'('' chgopt: LU decomp has an illegal value'')')
------------------------------------------------------------------------

Temporary workarounds: none