# Running a forward simulation using my own slip model returns an error

**URL:** <https://community.geodynamics.org/t/running-a-forward-simulation-using-my-own-slip-model-returns-an-error/3053>\
**Category:** PyLith\
**Created:** [July 29, 2023, 3:20am UTC](https://community.geodynamics.org/t/running-a-forward-simulation-using-my-own-slip-model-returns-an-error/3053 "2023-07-29T03:20:49Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![saeedmohanna](https://yyz2.discourse-cdn.com/flex036/user_avatar/community.geodynamics.org/saeedmohanna/32/1546_2.png) [@saeedmohanna](https://community.geodynamics.org/u/saeedmohanna)\
**Post date:** [July 29, 2023, 3:20am UTC](https://community.geodynamics.org/t/running-a-forward-simulation-using-my-own-slip-model-returns-an-error/3053/1 "2023-07-29T03:20:49Z")

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Hello,

When attempting to run a forward simulation, pylith (v2.2.2) displays the following error relating to reading the spatialdb file for slip after I run the command ‘pylith eqsim.cfg’ in terminal:

 ![issue](https://canada1.discourse-cdn.com/flex036/uploads/geodynamics/original/2X/b/bd2e698c3b9303f74154f609226d8069b51b1635.png)

I am confused as to why its experiencing this error. I ran the example provided without any issues. I use the exact same formatting as in the example for 2D reverse faulting’s eqsims. The main difference is this is being run in 3D. I cannot use a newer version of pylith as the mesh I am using is written for this version.

I have attached a .zip file showing what the spatial db file looks like.  
[eqslip.spatialdb.zip](https://community.geodynamics.org/uploads/short-url/3rY9vvHSdZRjRY0gSRmD1SO9Gan.zip) (628 Bytes)

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<div class="post-metadata">

**Author:** ![baagaard](https://yyz2.discourse-cdn.com/flex036/user_avatar/community.geodynamics.org/baagaard/32/615_2.png) [@baagaard](https://community.geodynamics.org/u/baagaard)\
**Post date:** [July 30, 2023, 1:36am UTC](https://community.geodynamics.org/t/running-a-forward-simulation-using-my-own-slip-model-returns-an-error/3053/2 "2023-07-30T01:36:39Z")

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There are a few couple with the spatial database.

1. For a 3D problem, you need to specify all 3 components of fault motion (left-lateral-slip, reverse-slip, and fault-opening).
2. The number of items should be the same for `value-names` and `value-units and match `num-values`.

Meshes constructed for PyLith v2 will work with v3; however, the `.cfg` files must be updated.

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<div class="post-metadata">

**Author:** ![saeedmohanna](https://yyz2.discourse-cdn.com/flex036/user_avatar/community.geodynamics.org/saeedmohanna/32/1546_2.png) [@saeedmohanna](https://community.geodynamics.org/u/saeedmohanna)\
**Post date:** [July 31, 2023, 8:04pm UTC](https://community.geodynamics.org/t/running-a-forward-simulation-using-my-own-slip-model-returns-an-error/3053/3 "2023-07-31T20:04:37Z")

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I just tried specifying all 3 components and ensuring the number of items for value-names, value-units = num-values = 3 (see attached .zip).

I get the following error:

 ![issue](https://canada1.discourse-cdn.com/flex036/uploads/geodynamics/original/2X/e/e45e13762f90f4dc9a7165f4080a50c6d2081921.png)

I re ran it and got the same error.

[eqslip.spatialdb.zip](https://community.geodynamics.org/uploads/short-url/wfXIPfDJAO8hYJkb3FuHMmzcekW.zip) (560 Bytes)

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<div class="post-metadata">

**Author:** ![baagaard](https://yyz2.discourse-cdn.com/flex036/user_avatar/community.geodynamics.org/baagaard/32/615_2.png) [@baagaard](https://community.geodynamics.org/u/baagaard)\
**Post date:** [July 31, 2023, 8:56pm UTC](https://community.geodynamics.org/t/running-a-forward-simulation-using-my-own-slip-model-returns-an-error/3053/4 "2023-07-31T20:56:17Z")

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Your header indicates you have 24 points (`num-locs=24`) but you only provide 18 points.