anchor.diff:       1 '                        3    2     2  6     '
             write(*,*)
        1 '                        :    :      :       '
  -      endif
  -C      write(*,*)
  -C     1 '-LQR|-SVD          Solve LS problem with QR/LQ factorization ',
  -C     2                     'or SVD (NO SVD OPTION YET!)'
  +          write(*,*)
  +      endif
         write(*,*)
        1 '-h                  Online help'
         write(*,*)
        1 '-d                  Detailed online help'
         write(*,*)
  -      write(*,*)
  -     1 '  *File format depends on 2-D or 3-D'
  -      write(*,*)
         STOP
         END
  -
  -C dgelsd (M,N,NRHS,A,LDA,B,LDB, S, RCOND, RANK, WORK, LWORK, IWORK, INFO)
  -C S(min(M,N))
  -C RCOND = tolerance fraction (Values of S < RCOND*S(1) are set to zero)
  -C RANK: integer
  -C IWORK(3*min(M,N)*nlvl+11*min(m,n))
  -
  
positive.code: 
  C----------------------------------------------------------------------C
  
        SUBROUTINE green3d(A,b,obs,flt,nobs,nflt)
        IMPLICIT none
        REAL*8 pi,d2r
        PARAMETER (pi=4.0d0*atan(1.0d0),d2r=pi/1.8d2)
        INTEGER OBSMAX,PARMAX
        PARAMETER (OBSMAX=10000,PARMAX=100)
        REAL*8 flt(PARMAX,7),obs(OBSMAX,6),A(OBSMAX,PARMAX),b(OBSMAX,1)
        INTEGER i,j,jj,nobs,nflt
        REAL*8 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 Poisson ratio = 0.25
        vp = 7.0d3
        vs = vp/dsqrt(3.0d0)
        dens = 3.0d3
  C Load model matrix, A
        slip = 1.0d0
        do 151 j = 1,nflt
            xflt = flt(j,1)
            yflt = flt(j,2)
  
negative.code:   151 continue
  C Load observation vector, b
        do 154 i = 1,nobs
            b(i,1)        = obs(i,4)
            b(i+nobs,1)   = obs(i,5)
            b(i+2*nobs,1) = obs(i,6)
    154 continue
  C In 3-D, each observation corresponds to three rows in A, b
  