<div style="line-height:1.7;color:#000000;font-size:14px;font-family:arial"><div style="line-height:1.7;color:#000000;font-size:14px;font-family:arial"><div style="line-height:1.7;color:#000000;font-size:14px;font-family:arial"><div style="line-height:1.7;color:#000000;font-size:14px;font-family:arial"><div style="line-height:1.7;color:#000000;font-size:14px;font-family:arial">i want to define a function for the computation of the equation residual in  a special way. </div><div style="line-height:1.7;color:#000000;font-size:14px;font-family:arial">does petsc provide this capbility<br><br><span title="neteasefooter"><span id="netease_mail_footer"></span></span></div><br><br><span title="neteasefooter"><span id="netease_mail_footer"></span></span></div><br><br><span title="neteasefooter"><span id="netease_mail_footer"></span></span></div><br><br><span title="neteasefooter"><span id="netease_mail_footer"></span></span></div><br><br><span title="neteasefooter"><span id=
 
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