You can download the source code of Yeti from this page. Instructions to build and install Yeti are given in the Installation Section.
The following Yeti source packages are available:
I have precompiled Yorick and Yeti on various architectures. The following packages are available:
Pre-compiled FFTW Library
For Yeti-FFTW plugin, you need FFTW version 2.1.5 (the new API in version 3 is not supported). You can download the code of FFTW from the official site then compile and install FFTW library yourself (you'll need the double precision version for Yeti). Otherwise, you can download and install one of the following precompiled versions: