anchor.diff:        COMMON /ZVARS0/ U3,V3,W3
         COMMON /PRODUCTS/ xx,xy,yy,dd,xd,xc,xq,yq,dq,pq
         COMMON /TAG/ thru
  +
  +      if (stdp.lt.0.0d0) then
  +          do 315 i = 1,3
  +              do 316 j = 1,3
  +                  strain(i,j) = 0.0d0
  + 316          continue
  + 315      continue
  +          return
  +      endif
   C----
         thru = 0
         do 306 i = 1,6
  
positive.code:       COMMON /ZVARS/ E3,F3,G3,H3,P3,Q3
        COMMON /MISC/ D11,Rd,Re,Rk,logRe,logRk,TH
        COMMON /TAG/ thru
  C----
  C Initialize partial derivative components
  C----
  
negative.code:       COMMON /ZVARS/ E3,F3,G3,H3,P3,Q3
        COMMON /MISC/ D11,Rd,Re,Rk,logRe,logRk,TH
        COMMON /TAG/ thru
        if (stdp.lt.0.0d0) then
            ux = 0.0d0
            uy = 0.0d0
            uz = 0.0d0
            return
        endif
  C----
  C Initialize displacement components
  C----
  