# An error occurs when I want to access the mesh information directly **URL:** \ **Category:** Using preCICE\ **Tags:** immersed-boundary, direct-mesh-access, fortran\ **Created:** [April 24, 2023, 5:35am UTC](https://precice.discourse.group/t/an-error-occurs-when-i-want-to-access-the-mesh-information-directly/1386 "2023-04-24T05:35:52Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![wufanxiaozi](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/wufanxiaozi/32/1643_2.png) [@wufanxiaozi](https://precice.discourse.group/u/wufanxiaozi)\ **Post date:** [April 24, 2023, 5:35am UTC](https://precice.discourse.group/t/an-error-occurs-when-i-want-to-access-the-mesh-information-directly/1386/1 "2023-04-24T05:35:52Z")
I want a fluid solver coupled to a solid solver for the Immersed Boundary Method. According to the official suggestion, I want to use this subroutine “precicef\_get\_mesh\_vertices\_and\_IDs()” to get the vertex coordinates of the solid mesh, but I can’t find him when compiling. I saw that this function is still in the experimental stage and may be changed later, but I am using the latest version of precice, who can tell me whether this function has changed? what should I do ? Can everyone help me! by wufan ---
**Author:** ![wufanxiaozi](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/wufanxiaozi/32/1643_2.png) [@wufanxiaozi](https://precice.discourse.group/u/wufanxiaozi)\ **Post date:** [April 24, 2023, 5:55am UTC](https://precice.discourse.group/t/an-error-occurs-when-i-want-to-access-the-mesh-information-directly/1386/2 "2023-04-24T05:55:15Z")
No error is reported for other precice’s subroutine used, but when using this function，I received an error “undefined reference to `precicef\_get\_mesh\_vertices\_and\_ids\_'” ---
**Author:** ![DavidSCN](https://avatars.discourse-cdn.com/v4/letter/d/c37758/32.png) [@DavidSCN](https://precice.discourse.group/u/DavidSCN)\ **Post date:** [April 24, 2023, 7:01am UTC](https://precice.discourse.group/t/an-error-occurs-when-i-want-to-access-the-mesh-information-directly/1386/3 "2023-04-24T07:01:45Z")
I guess your selected capitalization is wrong. This version should work > You can find out about such things on our doxygen page: [https://precice.org/doxygen/main/SolverInterfaceFortran\_8hpp.html](https://precice.org/doxygen/main/SolverInterfaceFortran_8hpp.html) I agree that having all caps `IDs` in this function name is inconsistent with the remaining API, we should probably change this part, thanks! ---
**Author:** ![wufanxiaozi](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/wufanxiaozi/32/1643_2.png) [@wufanxiaozi](https://precice.discourse.group/u/wufanxiaozi)\ **Post date:** [April 24, 2023, 7:25am UTC](https://precice.discourse.group/t/an-error-occurs-when-i-want-to-access-the-mesh-information-directly/1386/4 "2023-04-24T07:25:08Z")
Very happy with your reply, but it is case insensitive in Fortran. At the same time, I also changed to lowercase, and also reported this error ---
**Author:** ![wufanxiaozi](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/wufanxiaozi/32/1643_2.png) [@wufanxiaozi](https://precice.discourse.group/u/wufanxiaozi)\ **Post date:** [April 24, 2023, 7:40am UTC](https://precice.discourse.group/t/an-error-occurs-when-i-want-to-access-the-mesh-information-directly/1386/5 "2023-04-24T07:40:42Z")
This is my code ![image](https://global.discourse-cdn.com/free1/uploads/precice/original/2X/e/efdec5925de6761e1593e723731e867570441da3.png) and this is the error ![image](https://global.discourse-cdn.com/free1/uploads/precice/original/2X/5/5108b87e119c2c35411accf67da3b4bf14ec1340.png) ---
**Author:** ![DavidSCN](https://avatars.discourse-cdn.com/v4/letter/d/c37758/32.png) [@DavidSCN](https://precice.discourse.group/u/DavidSCN)\ **Post date:** [April 24, 2023, 7:44am UTC](https://precice.discourse.group/t/an-error-occurs-when-i-want-to-access-the-mesh-information-directly/1386/6 "2023-04-24T07:44:50Z")
Yes, you are right, the error message would also look different then. How did you install preCICE? ---
**Author:** ![wufanxiaozi](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/wufanxiaozi/32/1643_2.png) [@wufanxiaozi](https://precice.discourse.group/u/wufanxiaozi)\ **Post date:** [April 24, 2023, 8:04am UTC](https://precice.discourse.group/t/an-error-occurs-when-i-want-to-access-the-mesh-information-directly/1386/7 "2023-04-24T08:04:23Z")
Thank you DavidSCN, I compiled and installed the source code on the supercomputing machine. The quickstart and Perpendicular flap in the tutorial can be run, and I can also successfully run the calculation examples in the provided Fortran binding. ---
**Author:** ![wufanxiaozi](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/wufanxiaozi/32/1643_2.png) [@wufanxiaozi](https://precice.discourse.group/u/wufanxiaozi)\ **Post date:** [April 24, 2023, 8:33am UTC](https://precice.discourse.group/t/an-error-occurs-when-i-want-to-access-the-mesh-information-directly/1386/8 "2023-04-24T08:33:39Z")
Thank you David,Just now I compiled successfully, I don’t know where I modified, but it did succeed, thank you for your help. I also want to ask you a question, if I want to get the position of the solid mesh in the time loop, should I call the subroutine “precicef\_get\_mesh\_vertices\_and\_IDs” in the time loop? ---
**Author:** ![DavidSCN](https://avatars.discourse-cdn.com/v4/letter/d/c37758/32.png) [@DavidSCN](https://precice.discourse.group/u/DavidSCN)\ **Post date:** [April 24, 2023, 9:41am UTC](https://precice.discourse.group/t/an-error-occurs-when-i-want-to-access-the-mesh-information-directly/1386/9 "2023-04-24T09:41:41Z")
> [@wufanxiaozi](#): > > should I call the subroutine “precicef\_get\_mesh\_vertices\_and\_IDs” in the time loop? No, once before the time loop starts is sufficient, the meshes don’t change throughout the simulation. ---
**Author:** ![wufanxiaozi](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/wufanxiaozi/32/1643_2.png) [@wufanxiaozi](https://precice.discourse.group/u/wufanxiaozi)\ **Post date:** [April 24, 2023, 10:37am UTC](https://precice.discourse.group/t/an-error-occurs-when-i-want-to-access-the-mesh-information-directly/1386/10 "2023-04-24T10:37:40Z")
so，what should I do if I want to get solid mesh when the solid mesh deformed in time loop？ ---
**Author:** ![wufanxiaozi](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/wufanxiaozi/32/1643_2.png) [@wufanxiaozi](https://precice.discourse.group/u/wufanxiaozi)\ **Post date:** [April 24, 2023, 1:59pm UTC](https://precice.discourse.group/t/an-error-occurs-when-i-want-to-access-the-mesh-information-directly/1386/11 "2023-04-24T13:59:29Z")
I have a new problem, I set it up according to the tutorial, but when I use subrountine “precicef\_get\_mesh\_id(SolidMeshName, SolidMeshID)”, I get such an error message "preCICE:ERROR: The given Mesh ID “12395504” is unknown to preCICE .” Solid solver I used rigid\_body\_solver.cpp in quickstart, and modified it. I released the solid code and configuration files fluid solver: ![image](https://global.discourse-cdn.com/free1/uploads/precice/original/2X/b/b0de1a8315def4896a34b60feb7f1ba711d0dcfe.png) solid solver: ![image](https://global.discourse-cdn.com/free1/uploads/precice/original/2X/2/2971a0012edb8ae289cc12ebeb2ebdd927f0c1ae.png) precice-config.xml ![image](https://global.discourse-cdn.com/free1/uploads/precice/original/2X/e/efbeb59f897be89d8f63ca55668e97f8d1fb09e3.png) error: ![image](https://global.discourse-cdn.com/free1/uploads/precice/original/2X/0/0d5ff2eac570d0345991f894fb1eb8e4f524813a.png) ---
**Author:** ![wufanxiaozi](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/wufanxiaozi/32/1643_2.png) [@wufanxiaozi](https://precice.discourse.group/u/wufanxiaozi)\ **Post date:** [April 26, 2023, 6:41am UTC](https://precice.discourse.group/t/an-error-occurs-when-i-want-to-access-the-mesh-information-directly/1386/12 "2023-04-26T06:41:47Z")
I further pinned down the error on this line of code > CALL precicef\_set\_mesh\_access\_region(SolidMeshID, boundingBox) The error is “The given Mesh ID XXXX is unknown to preCICE” Even if I change the code to ` CALL precicef_set_mesh_access_region(0, boundingBox)` still the same error. ---
**Author:** ![wufanxiaozi](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/wufanxiaozi/32/1643_2.png) [@wufanxiaozi](https://precice.discourse.group/u/wufanxiaozi)\ **Post date:** [April 26, 2023, 6:45am UTC](https://precice.discourse.group/t/an-error-occurs-when-i-want-to-access-the-mesh-information-directly/1386/13 "2023-04-26T06:45:49Z")
I don’t know whether this command is necessary if I want to use “direct access to received meshes”. When I comment out this line of code, initialization succeeds. [https://precice.org/couple-your-code-direct-access.html](https://precice.org/couple-your-code-direct-access.html)