# Stall in some multi-node parallel calculations

**URL:** <https://community.freefem.org/t/stall-in-some-multi-node-parallel-calculations/1143>\
**Category:** General Discussion\
**Created:** [August 6, 2021, 11:36am UTC](https://community.freefem.org/t/stall-in-some-multi-node-parallel-calculations/1143 "2021-08-06T11:36:47Z")\
**Posts on this page:** 1\
**Showing post:** 71

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**Author:** ![etj](https://avatars.discourse-cdn.com/v4/letter/e/a698b9/32.png) [@etj](https://community.freefem.org/u/etj)\
**Post date:** [August 13, 2021, 8:32am UTC](https://community.freefem.org/t/stall-in-some-multi-node-parallel-calculations/1143/71 "2021-08-13T08:32:41Z")

</div>

In `FreeFem-sources/idp/`, after applying successively the 2 patches, and modifying line 251 of `macro_ddm.idp` as `for(int debugI = 0; debugI < 2*intersection[0].n; ++debugI) mpiWaitAny(rq);`, the output for `stokes-2d-PETSc.edp` is now:

```auto
-- FreeFem++ v4.9 (Fri Jun 18 14:45:02 CEST 2021 - git v4.9)
 Load: lg_fem lg_mesh lg_mesh3 eigenvalue parallelempi 
 load: init metis (v 5 )
 The Identifier intersection does not exist 

 Error line number 207, in file ../../idp/macro_ddm.idp, before token intersection

  current line = 207 mpirank 0 / 4
Compile error : 
	line number :207, intersection
  current line = 207 mpirank 2 / 4
error Compile error : 
	line number :207, intersection
 code = 1 mpirank: 0
  current line = 207 mpirank 1 / 4
  current line = 207 mpirank 3 / 4

```

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