<div>    Dear developers:</div>
<div>I use v4.2 do relax calculation,but it appears:</div>
<div>    </div>
<div>    Message from routine iosys:<br>     pot_extrapolation='second_order' not available, using 'atomic'<br>     Message from routine iosys:<br>     wfc_extrapolation='second_order' not available, using 'atomic'</div>

<div> </div>
<div>my input file is :</div>
<div>&control<br>    title='go'<br>    calculation='relax',<br>    restart_mode='from_scratch',<br>    prefix='go'<br>    pseudo_dir = '/home/sdwang/espresso-4.1.2/pseudo',<br>
    outdir='/home/sdwang/GO/go/tmp'<br>    tprnfor=.true.<br>    tstress=.true.<br>/<br>&system    <br>    ibrav = 8, celldm(1)=4.650,celldm(2)=1.7317, celldm(3)=7.3170 ,nat=6, ntyp=2,<br>    ecutwfc = 40.0,occupations='smearing',degauss=0.01,smearing='gaussian'<br>
/<br>&electrons<br>    mixing_beta = 0.7<br>    conv_thr =  1.0d-8<br>/<br>&ions<br> ion_dynamics='bfgs',<br> bfgs_ndim=1,<br> pot_extrapolation="second_order",<br> wfc_extrapolation="second_order",<br>
/<br>ATOMIC_SPECIES<br> C   12.0  C.pz-vbc.UPF<br> O   16.0  O.pz-mt.UPF   <br>ATOMIC_POSITIONS (crystal)<br>C     0.24680   0.16962   0.07944<br>C     0.74680   0.33632   0.07944<br>C     0.24680   0.83642   0.07944<br>C     0.74680   0.66972   0.07944<br>
O     0.77674   0.49750   0.15405<br>O     0.23131   0.98180   0.00297<br>K_POINTS (automatic)<br>7 7 1 0 00</div>
<div>What is the problem?</div>
<div>Thanks!</div>
<div> </div>
<div>S D Wang</div>