## 4.3. Decomposing Unstructured Calculations

The decomposition of unstructured parts is applied automatically in a similar method to the decomposition of SPH grids.

Load in CYRAIL from the samples directory within the Workbench distribution.

Convert this structured model into unstructured parts by selecting the Import > Convert IJK Parts to Unstructured menu item and selecting all of the available options:

This makes two unstructured parts called VOLUME 1 and VOLUME 2. Rename these parts to TARG and CYLINDER in the parts menu.

Go to the Parallel panel and tick the box to activate parallel processing. Add a decomposition set and call it TWO:

You will see that there are two sections within the Decomposition Sets area of the menu (Manual and Automatic). For unstructured parts, the second section should be used. Clicking Set Decompositions activates a window in which the information regarding the decomposition can be entered:

All the unstructured parts within the model will be displayed in the Parts to be decomposed window and all are highlighted by default. To decompose the model over two tasks (task 1 and task 2) enter `2` into the Number of Tasks box and click Decompose Now:

Click the check button.

Select the Plot parallel decomposition option in the Parallel Processing window if you want to see the parallel decomposition.

If you want to decompose the part TARG in Task 2, click Set Decomposition again and highlight only TARG, enter `2` into the Start Task box, and click Decompose Now:

In a similar manner the model can be decomposed over 4 slaves:

and over 8 slaves:

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