<div dir="ltr"><div>Hi,</div><div><br></div><div>I am trying to compile Fortran code with PETSc 3.16 built without MPI, i.e., --with-mpi=0, and am getting the following error:</div><div><br></div><div><font face="monospace">   call MPI_Comm_rank(MPI_COMM_WORLD,rank,ierr)<br>                                         1<br>Error: Symbol ‘mpi_comm_world’ at (1) has no IMPLICIT type</font><br></div><div><br></div><div>There are no issues with PETSc 3.14 or prior versions. Any ideas as to what could be wrong?</div><div><br></div><div>I do see the following note (below) in <a href="https://petsc.org/main/docs/changes/315/">https://petsc.org/main/docs/changes/315/</a> but I am not sure if it's related:</div><div><div><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol""><br></span></div><div><i><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol"">Add configure option </span><code class="gmail-docutils gmail-literal gmail-notranslate" style="color:rgb(51,51,51);box-sizing:border-box;font-size:14px"><span class="gmail-pre" style="box-sizing:border-box">--with-mpi-f90module-visibility</span></code><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol""> </span><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol"">[default=``1``]. With</span><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol""> </span><code class="gmail-docutils gmail-literal gmail-notranslate" style="color:rgb(51,51,51);box-sizing:border-box;font-size:14px"><span class="gmail-pre" style="box-sizing:border-box">0</span></code><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol"">,</span><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol""> </span><code class="gmail-docutils gmail-literal gmail-notranslate" style="color:rgb(51,51,51);box-sizing:border-box;font-size:14px"><span class="gmail-pre" style="box-sizing:border-box">mpi.mod</span></code><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol""> </span><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol"">will not be visible in use code (via</span><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol""> </span><code class="gmail-docutils gmail-literal gmail-notranslate" style="color:rgb(51,51,51);box-sizing:border-box;font-size:14px"><span class="gmail-pre" style="box-sizing:border-box">petscsys.mod</span></code><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol"">) - so</span><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol""> </span><code class="gmail-docutils gmail-literal gmail-notranslate" style="color:rgb(51,51,51);box-sizing:border-box;font-size:14px"><span class="gmail-pre" style="box-sizing:border-box">mpi_f08</span></code><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol""> </span><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol"">can now be used</span></i></div></div><div><i><span style="font-size:1em;color:rgb(51,51,51);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol""><br></span></i></div><div>Regards,</div><div><br></div><div>Tabrez</div></div>