From OS X Scientific Computing
What is it?
Are there other options?
The main alternative is MacPorts (formerly DarwinPorts). I don't use it much because fink seems to have more scientific-related software. However, the two can peacefully coexist (they are cooperative projects, not competitors for your free software dollars).
Also, many third-party unix programs can be installed into /usr/local manually without fanfare. Many people prefer to do things that way. Package management systems exist to help ease the burden of system administration and keeping things up to date and running, but you should not feel obligated to make use of them.
Having said that, you are nuts if you don't, or at least have way more spare time on your hands than I do.
Do this First
Be sure you have the most current release.
Almost everything you need in Fink assumes you have installed X11. Be sure to do this before you begin.
Apple has dropped X11 again, so we are back to installing a third-party application. Fortunately, this appears to be fairly seamless, thanks to the Xquartz project.
Download Xquartz X11 and install it. It will install into /opt/X11
Installing Fink on 10.11
Please go to the page entitled Fink_for_10.11
Getting your fink installation to use packages that I have pre-compiled
Please go to the page Getting your fink installation to use packages that I have pre-compiled