anchor.diff:  C Command line inputs
         CHARACTER*80 fltf,obsf,smoof,haff,ofile,annf
         REAL*8 smooth,damp
  -      INTEGER geo,p,invert,vrb
  +      INTEGER geo,p,invert,vrb,ostyle
   C Inversion array variables
         INTEGER nobs,OBSMAX,nflt,FLTMAX
         PARAMETER (OBSMAX=500,FLTMAX=500)
  
positive.code:       temp = temp0
        do 520 i = 1,nitmax
            do 514 j = 1,nflt
  C             Gibbs sampler: create variable PDFs; directly sample
                denom = 0.0d0
                do 508 jj = 1,int(slip(j,3)+0.1)
                    soln(j,1) = slip(j,1) + (dble(jj)-0.5d0)*dslip(j)
                    call calcobj(obj,misfit,length,rough,soln,gf,obs,nobs,
       1                         OBSMAX,nflt,FLTMAX,damp,smooth,smarry,
       2                         nsmoo)
                    if (obj/temp.gt.50.0d0) then
                        energy(jj) = 0.0d0
                    else
                        energy(jj) = exp(-obj/temp)
                    endif
                    denom = denom + energy(jj)
    508         continue
                test = 0.0d0
                do 509 jj = 1,int(slip(j,3)+0.1)
                    test = test + energy(jj)/denom
                    if (ran2(idum).lt.test) then ! Sample PDF
                        goto 510
                    endif
    509         continue
    510         soln(j,1) = slip(j,1) + (dble(jj)-0.5d0)*dslip(j)
                denom = 0.0d0
                do 511 jj = 1,int(rake(j,3)+0.1)
                    soln(j,2) = rake(j,1) + (dble(jj)-0.5d0)*drake(j)
                    call calcobj(obj,misfit,length,rough,soln,gf,obs,nobs,
       1                         OBSMAX,nflt,FLTMAX,damp,smooth,smarry,
       2                         nsmoo)
                    if (obj/temp.gt.50.0d0) then
                        energy(jj) = 0.0d0
                    else
                        energy(jj) = exp(-obj/temp)
                    endif
                    denom = denom + energy(jj)
    511         continue
                test = 0.0d0
                do 512 jj = 1,int(rake(j,3)+0.1)
                    test = test + energy(jj)/denom
                    if (ran2(idum).lt.test) then ! Sample PDF
                        goto 513
                    endif
    512         continue
    513         soln(j,2) = rake(j,1) + (dble(jj)-0.5d0)*drake(j)
    514     continue
  C         Compute objective function for new model
            call calcobj(obj,misfit,length,rough,soln,gf,obs,nobs,OBSMAX,
       1                 nflt,FLTMAX,damp,smooth,smarry,nsmoo)
  C         Record results in log files
  
negative.code:       p = 0
        invert = 0
        vrb = 0
        ostyle = 0
        indx = 0
        narg = iargc()
        if (narg.eq.0) call usage('!! Error: no command line arguments')
  