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Building a Cosmic Emulator
In
order to build an emulator several steps have to be carried
out. First, one has to generate the predictions from a set of
cosmologies spanning the parameter space of interest. From these
predictions, an interpolation scheme has to be build. In our case,
we obtain the predictions for the power spectra from a set of
high-performance precision simulations. The cosmological models
are selected via an orthogonal array Latin Hypercube design and the emulator itself is generated using Gaussian Process Modeling.
Many details on the procedure can be found in our
papers
and selected presentations.
Emulator for the Nonlinear Matter Power
Spectrum
The first emulator we release is for
the nonlinear matter power spectrum. We provide predictions
out to k~1 h/Mpc at high accuracy and for redshifts between z=0
and z=1. The emulator package is a C code. The
code can be
downloaded here. Please
read the readme.txt carefully for compile and run instructions.
Update: Version 1.1 now available
The updated emulator version now has the redshift as a separate
input, so one can choose any redshift between z=0 and z=1. In
addition, the new version includes the Fortran wrapper to make the
code easy to use with already existing software, such as
CosmoMC. We provide to makefile, makefileC and makefileF. Copy the
one you would like to use into makefile and simply do make. The
fortran code works with the gnu-compiler. The main code mainF.f
should be easily modifiable. The code can be downloaded here. New: (Sept. 08,
2010) We added some lines to emu.c to free up memory which is
important for calculating multiple power spectra. Thanks to Tim
Eifler for pointing this out.
Mailing list
If you are interested in receiving emails
about updates and news on the cosmic emulators, please send an email to
heitmann.at.lanl.gov. We have set up a new email list, cosmicemu.at.lanl.gov.
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