modifying_surrogate_model.rst.txt 1.33 KB
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=========================
Modifying surrogate model
=========================

This tutorial extends the previous one for TiO clusters,
:ref:`searching for TiO clusters <searching-for-TiO-clusters>`. It is
therefore recomended that you do that one before the present one.

In the avove mentioned tutorial GOFEE was initialized with the following
arguments::
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    search = GOFEE(calc=calc,
                   startgenerator=sg,
                   candidate_generator=candidate_generator,
                   max_steps=100,
                   population_size=5)

however GOFEE takes a number of other arguments, including a
Gaussian Process regression (GPR) model, which is actively learned
during the search and used for cheap optimization of new candidates.

One can for example apply a GPR model with another degree of regularization
in the search. As the regularization is a parameter of the *kernel*, passed
to the GPR model, the code will look like this::

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    from gofee.surrogate.gpr import GPR
    from gofee.surrogate.kernel import double_gauss_kernel
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    kernel = double_gauss_kernel(noise=1e-6)
    gpr = GPR(kernel=kernel)

    search = GOFEE(calc=calc,
                   gpr=gpr,
                   startgenerator=sg,
                   candidate_generator=candidate_generator,
                   max_steps=100,
                   population_size=5)