# MPI REDUCE with sparse matrices

**URL:** https://community.freefem.org/t/mpi-reduce-with-sparse-matrices/2600
**Category:** General Discussion
**Created:** [July 12, 2023, 3:22pm UTC](https://community.freefem.org/t/mpi-reduce-with-sparse-matrices/2600 "2023-07-12T15:22:14Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![Loic](https://avatars.discourse-cdn.com/v4/letter/l/e9c0ed/32.png) [@Loic](https://community.freefem.org/u/Loic)
#### Post date: [July 12, 2023, 3:22pm UTC](https://community.freefem.org/t/mpi-reduce-with-sparse-matrices/2600/1 "2023-07-12T15:22:14Z")

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Hello all,

When doing MPI REDUCE on sparse matrices,  
Does anyone know what this problem means ? and how to solve it ?

```plaintext
6 **** MPI_Reduce sparse matrix: warning missing term in pattern 300
3 **** MPI_Reduce sparse matrix: warning missing term in pattern 300
3 **** MPI_Reduce sparse matrix: warning missing term in pattern 20
6 **** MPI_Reduce sparse matrix: warning missing term in pattern 20

```

Thank you in advance,

Best regards,

Loïc,