# Results of the LUBBY2 problem

**URL:** <https://discourse.opengeosys.org/t/results-of-the-lubby2-problem/1100>\
**Category:** Help & Support\
**Created:** [December 28, 2022, 4:13pm UTC](https://discourse.opengeosys.org/t/results-of-the-lubby2-problem/1100 "2022-12-28T16:13:21Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Mohamad](https://discourse.opengeosys.org/letter_avatar_proxy/v4/letter/m/ba9def/32.png) [@Mohamad](https://discourse.opengeosys.org/u/Mohamad)\
**Post date:** [December 28, 2022, 4:13pm UTC](https://discourse.opengeosys.org/t/results-of-the-lubby2-problem/1100/1 "2022-12-28T16:13:21Z")

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Hallo everyone,

after solving the LUBBY2 problem, i plotted the results (displacement versus time) usng ParaView. I noticed that the results i got show a linear relation between the two aforementioned variables. Whereas the results on the OGS website show a nonlinear relation. Can somebody help me?

Thank you in advance

 ![image](https://discourse.opengeosys.org/uploads/default/original/1X/f2465d79dfd9d231ae384d31b2040f1fb913e782.png)

 ![image](https://discourse.opengeosys.org/uploads/default/original/1X/47f6df1601b36fb571859ffc5477014c9869e614.png)

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<div class="post-metadata">

**Author:** ![chleh](https://discourse.opengeosys.org/user_avatar/discourse.opengeosys.org/chleh/32/854_2.png) [@chleh](https://discourse.opengeosys.org/u/chleh)\
**Post date:** [January 2, 2023, 6:50am UTC](https://discourse.opengeosys.org/t/results-of-the-lubby2-problem/1100/2 "2023-01-02T06:50:59Z")

</div>

Hi Mohamad,

I guess you are referring to [this test case](https://www.opengeosys.org/docs/benchmarks/small-deformations/mechanics-lubby2-shear-traction/) with [this prj file](https://gitlab.opengeosys.org/ogs/ogs/-/blob/master/Tests/Data/Mechanics/Burgers/cube_1e3.prj)

In the test OGS first makes one time step of 0.0001 s and afterwards several 0.01 s timesteps:

```auto
                <time_stepping>
                    <type>FixedTimeStepping</type>
                    <t_initial>0</t_initial>
                    <t_end>1</t_end>
                    <timesteps>
                        <pair>
                            <repeat>1</repeat>
                            <delta_t>0.0001</delta_t>
                        </pair>
                        <pair>
                            <repeat>100</repeat>
                            <delta_t>0.01</delta_t>
                        </pair>
                    </timesteps>
                </time_stepping>

```

However, OGS only outputs the initial condition, the first timestep and the last timestep:

```auto
        <output>
            <type>VTK</type>
            <prefix>cube_1e3</prefix>
            <timesteps>
                <pair>
                    <repeat>1</repeat>
                    <each_steps>1</each_steps>
                </pair>
                <pair>
                    <repeat>1</repeat>
                    <each_steps>10000000</each_steps>
                </pair>
            </timesteps>
            ...
        </output>

```

If you change the output configuration to the following you should see the desired nonlinear curve:

```auto
        <output>
            <type>VTK</type>
            <prefix>cube_1e3</prefix>
            <timesteps>
                <pair>
                    <repeat>1000</repeat>
                    <each_steps>1</each_steps>
                </pair>
            </timesteps>
            ...
        </output>

```

Since our test cases are run very often during the OGS development we typically reduce them to the bare minimum, e.g. by restriciting output or limiting the simulation time.