span>
  model.zsrc = d(1):d(1)*2:d(1)*(n(1)-2);
  model.xsrc = d(1)*2;
  model.zrec = d(1):d(1):d(1)*(n(1)-2);
  model.xrec = d(1)*(n(1)-2);

  [zz xx] = odn2grid(o,d,n);

<span class="comment">% The true model and initial model are</span>
  figure;subplot(1,2,1)
  imagesc(zz,xx,vel);xlabel(<span class="string">'X [m]'</span>);ylabel(<span class="string">'Z [m]'</span>);a =caxis;colorbar
  title(<span class="string">'True model'</span>)

  subplot(1,2,2)
  imagesc(zz,xx,velini);xlabel(<span class="string">'