.. _method-coliny_solis_wets-no_expansion:

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no_expansion
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Don't allow expansion of the search pattern


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**Specification**

- *Alias:* None

- *Arguments:* None

- *Default:* algorithm may expand pattern size


**Description**


In general, pattern search methods can expand and contract their step
lengths.  SCOLIB pattern search methods contract the step length by
the value ``contraction_factor``, and they expand the step length by
the value (1/contraction_factor).  The ``expand_after_success`` control
specifies how many successful objective function improvements must
occur with a specific step length prior to expansion of the step
length, whereas the ``no_expansion`` flag instructs the algorithm to
forgo pattern expansion altogether.