# Error in parallel unstructured VTKHDF file

**URL:** https://discourse.vtk.org/t/error-in-parallel-unstructured-vtkhdf-file/13961
**Category:** Support
**Created:** [May 31, 2024, 2:03pm UTC](https://discourse.vtk.org/t/error-in-parallel-unstructured-vtkhdf-file/13961 "2024-05-31T14:03:30Z")
**Posts on this page:** 4
**Page:** 1

<div class="post-metadata">

### Author: ![sori](https://discourse.vtk.org/user_avatar/discourse.vtk.org/sori/32/8920_2.png) [@sori](https://discourse.vtk.org/u/sori)
#### Post date: [May 31, 2024, 2:03pm UTC](https://discourse.vtk.org/t/error-in-parallel-unstructured-vtkhdf-file/13961/1 "2024-05-31T14:03:30Z")

</div>

Hello,

I’m trying to make my own parallel VTKHDF writing routine.  
For the serial execution, the output file looks fine and it could be opened well through Paraview.  
However, for the parallel run, the mesh doesn’t show nicely as was intended (also sometimes Paraview is killed).  
I couldn’t find any clue for the fix.  
Below I attached h5dump output of the serial and parallel files.  
Thank you in advance!

Serial

```auto
HDF5 "output.hdf" {
GROUP "/" {
   GROUP "VTKHDF" {
      ATTRIBUTE "Type" {
         DATATYPE H5T_STRING {
            STRSIZE 16;
            STRPAD H5T_STR_NULLTERM;
            CSET H5T_CSET_ASCII;
            CTYPE H5T_C_S1;
         }
         DATASPACE SCALAR
         DATA {
         (0): "UnstructuredGrid"
         }
      }
      ATTRIBUTE "Version" {
         DATATYPE H5T_STD_I32LE
         DATASPACE SIMPLE { ( 2 ) / ( 2 ) }
         DATA {
         (0): 2, 0
         }
      }
      DATASET "Connectivity" {
         DATATYPE H5T_STD_I32LE
         DATASPACE SIMPLE { ( 144 ) / ( 144 ) }
         DATA {
         (0): 16, 9, 2, 18, 11, 19, 3, 10, 9, 16, 2, 1, 2, 9, 10, 18, 2, 18,
         (18): 14, 16, 8, 5, 12, 15, 12, 13, 7, 8, 18, 2, 14, 10, 16, 15, 9,
         (35): 18, 3, 19, 11, 13, 15, 6, 16, 5, 15, 14, 18, 16, 6, 15, 16,
         (51): 14, 0, 3, 8, 7, 1, 0, 8, 5, 13, 3, 8, 11, 3, 13, 8, 7, 2, 14,
         (70): 6, 16, 4, 7, 8, 12, 8, 7, 4, 0, 8, 5, 4, 12, 4, 5, 8, 0, 7,
         (89): 17, 14, 6, 2, 14, 17, 6, 3, 10, 17, 2, 3, 17, 10, 19, 14, 17,
         (106): 10, 2, 14, 10, 17, 19, 16, 15, 1, 9, 16, 1, 15, 5, 8, 1, 15,
         (123): 9, 8, 15, 1, 5, 3, 13, 17, 19, 3, 17, 13, 7, 14, 17, 13, 19,
         (140): 14, 13, 17, 7
         }
      }
      DATASET "NumberOfCells" {
         DATATYPE H5T_STD_I32LE
         DATASPACE SIMPLE { ( 1 ) / ( 1 ) }
         DATA {
         (0): 36
         }
      }
      DATASET "NumberOfConnectivityIds" {
         DATATYPE H5T_STD_I32LE
         DATASPACE SIMPLE { ( 1 ) / ( 1 ) }
         DATA {
         (0): 144
         }
      }
      DATASET "NumberOfPoints" {
         DATATYPE H5T_STD_I32LE
         DATASPACE SIMPLE { ( 1 ) / ( 1 ) }
         DATA {
         (0): 20
         }
      }
      DATASET "Offsets" {
         DATATYPE H5T_STD_I32LE
         DATASPACE SIMPLE { ( 37 ) / ( 37 ) }
         DATA {
         (0): 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60,
         (16): 64, 68, 72, 76, 80, 84, 88, 92, 96, 100, 104, 108, 112, 116,
         (30): 120, 124, 128, 132, 136, 140, 144
         }
      }
      DATASET "Points" {
         DATATYPE H5T_IEEE_F64LE
         DATASPACE SIMPLE { ( 20, 3 ) / ( 20, 3 ) }
         DATA {
         (0,0): 0, 0, 0,
         (1,0): 0.294, 0, 0,
         (2,0): 0.294, 0.294, 0,
         (3,0): 0, 0.294, 0,
         (4,0): 0.018, 0.018, 0,
         (5,0): 0.126, 0.018, 0,
         (6,0): 0.126, 0.126, 0,
         (7,0): 0.018, 0.126, 0,
         (8,0): 0, 0, 0.019,
         (9,0): 0.294, 0, 0.019,
         (10,0): 0.294, 0.294, 0.019,
         (11,0): 0, 0.294, 0.019,
         (12,0): 0.018, 0.018, 0.019,
         (13,0): 0.018, 0.126, 0.019,
         (14,0): 0.126, 0.126, 0.019,
         (15,0): 0.126, 0.018, 0.019,
         (16,0): 0.211929, 0.0987857, 0,
         (17,0): 0.0987857, 0.211929, 0,
         (18,0): 0.211929, 0.0987857, 0.019,
         (19,0): 0.0987857, 0.211929, 0.019
         }
      }
      DATASET "Types" {
         DATATYPE H5T_STD_U8LE
         DATASPACE SIMPLE { ( 36 ) / ( 36 ) }
         DATA {
         (0): 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
         (16): 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
         (31): 10, 10, 10, 10, 10
         }
      }
   }
}
}

```

Parallel

```auto
HDF5 "output.hdf" {
GROUP "/" {
   GROUP "VTKHDF" {
      ATTRIBUTE "Type" {
         DATATYPE H5T_STRING {
            STRSIZE 16;
            STRPAD H5T_STR_NULLTERM;
            CSET H5T_CSET_ASCII;
            CTYPE H5T_C_S1;
         }
         DATASPACE SCALAR
         DATA {
         (0): "UnstructuredGrid"
         }
      }
      ATTRIBUTE "Version" {
         DATATYPE H5T_STD_I32LE
         DATASPACE SIMPLE { ( 2 ) / ( 2 ) }
         DATA {
         (0): 2, 0
         }
      }
      DATASET "Connectivity" {
         DATATYPE H5T_STD_I32LE
         DATASPACE SIMPLE { ( 144 ) / ( 144 ) }
         DATA {
         (0): 15, 8, 2, 16, 10, 17, 3, 9, 8, 15, 2, 1, 2, 8, 9, 16, 2, 16,
         (18): 13, 15, 7, 4, 11, 14, 11, 12, 6, 7, 16, 2, 13, 9, 15, 14, 8,
         (35): 16, 3, 17, 10, 12, 14, 5, 15, 4, 14, 13, 16, 15, 5, 14, 15,
         (51): 13, 0, 3, 7, 6, 1, 0, 7, 4, 12, 3, 7, 10, 3, 12, 7, 6, 2, 13,
         (70): 5, 15, 18, 6, 7, 11, 7, 6, 18, 0, 7, 4, 18, 11, 18, 4, 7, 0,
         (88): 6, 19, 13, 5, 2, 13, 19, 5, 3, 9, 19, 2, 3, 19, 9, 17, 13, 19,
         (106): 9, 2, 13, 9, 19, 17, 15, 14, 1, 8, 15, 1, 14, 4, 7, 1, 14, 8,
         (124): 7, 14, 1, 4, 3, 12, 19, 17, 3, 19, 12, 6, 13, 19, 12, 17, 13,
         (141): 12, 19, 6
         }
      }
      DATASET "NumberOfCells" {
         DATATYPE H5T_STD_I32LE
         DATASPACE SIMPLE { ( 2 ) / ( 2 ) }
         DATA {
         (0): 18, 18
         }
      }
      DATASET "NumberOfConnectivityIds" {
         DATATYPE H5T_STD_I32LE
         DATASPACE SIMPLE { ( 2 ) / ( 2 ) }
         DATA {
         (0): 72, 72
         }
      }
      DATASET "NumberOfPoints" {
         DATATYPE H5T_STD_I32LE
         DATASPACE SIMPLE { ( 2 ) / ( 2 ) }
         DATA {
         (0): 18, 2
         }
      }
      DATASET "Offsets" {
         DATATYPE H5T_STD_I32LE
         DATASPACE SIMPLE { ( 38 ) / ( 38 ) }
         DATA {
         (0): 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60,
         (16): 64, 68, 72, 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48,
         (32): 52, 56, 60, 64, 68, 72
         }
      }
      DATASET "Points" {
         DATATYPE H5T_IEEE_F64LE
         DATASPACE SIMPLE { ( 20, 3 ) / ( 20, 3 ) }
         DATA {
         (0,0): 0, 0, 0,
         (1,0): 0.294, 0, 0,
         (2,0): 0.294, 0.294, 0,
         (3,0): 0, 0.294, 0,
         (4,0): 0.126, 0.018, 0,
         (5,0): 0.126, 0.126, 0,
         (6,0): 0.018, 0.126, 0,
         (7,0): 0, 0, 0.019,
         (8,0): 0.294, 0, 0.019,
         (9,0): 0.294, 0.294, 0.019,
         (10,0): 0, 0.294, 0.019,
         (11,0): 0.018, 0.018, 0.019,
         (12,0): 0.018, 0.126, 0.019,
         (13,0): 0.126, 0.126, 0.019,
         (14,0): 0.126, 0.018, 0.019,
         (15,0): 0.211929, 0.0987857, 0,
         (16,0): 0.211929, 0.0987857, 0.019,
         (17,0): 0.0987857, 0.211929, 0.019,
         (18,0): 0.018, 0.018, 0,
         (19,0): 0.0987857, 0.211929, 0
         }
      }
      DATASET "Types" {
         DATATYPE H5T_STD_U8LE
         DATASPACE SIMPLE { ( 36 ) / ( 36 ) }
         DATA {
         (0): 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
         (16): 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
         (31): 10, 10, 10, 10, 10
         }
      }
   }
}
}

```

---

<div class="post-metadata">

### Author: ![lgivord](https://discourse.vtk.org/user_avatar/discourse.vtk.org/lgivord/32/3543_2.png) [@lgivord](https://discourse.vtk.org/u/lgivord)
#### Post date: [June 3, 2024, 6:17am UTC](https://discourse.vtk.org/t/error-in-parallel-unstructured-vtkhdf-file/13961/2 "2024-06-03T06:17:03Z")

</div>

hello @sori,

UnstructuredGrid in parallel is expected to work, however just with a dump its a bit hard, I could find what is missing in your file if you can share it (your .vtkhdf file in parallel and in serial would be nice).

Bests,

---

<div class="post-metadata">

### Author: ![sori](https://discourse.vtk.org/user_avatar/discourse.vtk.org/sori/32/8920_2.png) [@sori](https://discourse.vtk.org/u/sori)
#### Post date: [June 3, 2024, 6:33am UTC](https://discourse.vtk.org/t/error-in-parallel-unstructured-vtkhdf-file/13961/3 "2024-06-03T06:33:19Z")

</div>

Hello @lgivord, and thank you for reply!  
I was not able to upload hdf file because I’m a new user.

And… I just realized that I’ve been erroneously using the “global” index for the index data.  
It was fixed by duplicating `Points` data on multiple processes and use “local” index for the `Connectivity` data.

I think the problem is related to the previous one, but I didn’t notice [VTKHDF point ownership - Support - VTK](https://discourse.vtk.org/t/vtkhdf-point-ownership/13913).

Thank you

---

<div class="post-metadata">

### Author: ![lgivord](https://discourse.vtk.org/user_avatar/discourse.vtk.org/lgivord/32/3543_2.png) [@lgivord](https://discourse.vtk.org/u/lgivord)
#### Post date: [June 3, 2024, 6:39am UTC](https://discourse.vtk.org/t/error-in-parallel-unstructured-vtkhdf-file/13961/4 "2024-06-03T06:39:09Z")

</div>

Nice!