anchor.diff:            wid = flt(j,6)
             len = flt(j,7)
   C         variables for rotating to fault reference frame
  -          t = d2r*(90.0d0-str)
  +          t = d2r*(90.0d0-str) ! t for "theta"
             cost = dcos(t)
             sint = dsin(t)
             do 152 i = 1,nobs
  
positive.code: 
  C----------------------------------------------------------------------C
  
        SUBROUTINE lsq(Ain,bin,xout,OBSMAX,PARMAX,nobs,npar)
  C----
  C Solve generalized least squares problem Ax = b.
  C On input, arrays Ain and bin are given maximum dimensions:
  C     Ain(OBSMAX,PARMAX)
  C     bin(OBSMAX,1)
  C To operate with LAPACK generalized inverse tools, convert arrays from
  C maximum size to operating size:
  
negative.code: 
  C----------------------------------------------------------------------C
  
        SUBROUTINE green3d(A,b,obs,flt,nobs,nflt,haf)
  C----
  C Create Green's functions for 3-D case and load model matrix.
  C----
        IMPLICIT none
        REAL*8 pi,d2r
        PARAMETER (pi=4.0d0*atan(1.0d0),d2r=pi/1.8d2)
        INTEGER OBSMAX,FLTMAX
        PARAMETER (OBSMAX=2500,FLTMAX=2000)
        REAL*8 obs(OBSMAX,6),flt(FLTMAX,7)
        REAL*8 A(OBSMAX,FLTMAX),b(OBSMAX,1)
        INTEGER i,j,jj,nobs,nflt
        REAL*8 haf(3),vp,vs,dens
        REAL*8 xflt,yflt,zflt,xobs,yobs,zobs,dx,dy
        REAL*8 wid,len,dip,rak,slip,str
        REAL*8 gfx,gfy,gfz
        REAL*8 ddip,dstr,t,cost,sint
  C Half-space properties
        vp = haf(1)
        vs = haf(2)
        dens = haf(3)
        print *,haf(1),haf(2),haf(3)
  C Compute Green's functions and load model matrix, A
        slip = 1.0d0 ! unit slip for Green's functions
        do 151 j = 1,nflt
            xflt = flt(j,1)
            yflt = flt(j,2)
  