# Umfpack\_di\_numeric failed error **URL:** \ **Category:** General Discussion\ **Created:** [September 28, 2023, 2:37pm UTC](https://community.freefem.org/t/umfpack-di-numeric-failed-error/2731 "2023-09-28T14:37:28Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![M\_Usman](https://avatars.discourse-cdn.com/v4/letter/m/e5b9ba/32.png) [@M\_Usman](https://community.freefem.org/u/M_Usman)\ **Post date:** [September 28, 2023, 2:37pm UTC](https://community.freefem.org/t/umfpack-di-numeric-failed-error/2731/1 "2023-09-28T14:37:28Z")
I am trying to solve natural convection flow inside a square cavity for a higher value of Rayleigh number (Ra=10^8), for this I took mesh = 200 but received “umfpack\_di\_numeric failed” error. How to deal with this problem? ---
**Author:** ![frederichecht](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/frederichecht/32/15_2.png) [@frederichecht](https://community.freefem.org/u/frederichecht)\ **Post date:** [September 28, 2023, 4:21pm UTC](https://community.freefem.org/t/umfpack-di-numeric-failed-error/2731/2 "2023-09-28T16:21:51Z")
I thick you matrix is not invertible or to big ---
**Author:** ![M\_Usman](https://avatars.discourse-cdn.com/v4/letter/m/e5b9ba/32.png) [@M\_Usman](https://community.freefem.org/u/M_Usman)\ **Post date:** [September 29, 2023, 1:02am UTC](https://community.freefem.org/t/umfpack-di-numeric-failed-error/2731/3 "2023-09-29T01:02:49Z")
Thank you Professor @frederichecht , how I can overcome this problem? ---
**Author:** ![frederichecht](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/frederichecht/32/15_2.png) [@frederichecht](https://community.freefem.org/u/frederichecht)\ **Post date:** [October 1, 2023, 8:47am UTC](https://community.freefem.org/t/umfpack-di-numeric-failed-error/2731/4 "2023-10-01T08:47:13Z")
Debug, I try to under where is the problem.