Eigen is a C++ template library for linear algebra: matrices, vectors, numerical solvers, and related algorithms. I've been having trouble installing it. When I ran cmake '/home/brentonhorne/eigen-eigen-5097c01bcdc4 where /home/brentonhorne/eigen-eigen-5097c01bcdc4 is the location of the source directory extracted from the tarball I downloaded from the Eigen website, I received the error:

CMake Error at CMakeLists.txt:8 (message):

In-source builds not allowed.  Please make a new directory (called a build

directory) and run CMake from there.  You may need to remove

CMakeCache.txt.





-- Configuring incomplete, errors occurred!

Please tell me how to get past this roadblock. I do not understand much programming but if you can explain to me what I need to do in terms of what to paste into terminal I can do it! If it is needed to help me I am running 12.10.

If you need to know the contents of the INSTALL file in the source directory here they are:

Installation instructions for Eigen

***********************************



Explanation before starting

***************************



Eigen consists only of header files, hence there is nothing to compile

before you can use it. Moreover, these header files do not depend on your

platform, they are the same for everybody.



Method 1. Installing without using CMake

****************************************



You can use right away the headers in the Eigen/ subdirectory. In order

to install, just copy this Eigen/ subdirectory to your favorite location.

If you also want the unsupported features, copy the unsupported/

subdirectory too.



Method 2. Installing using CMake

********************************



Let's call this directory 'source_dir' (where this INSTALL file is).

Before starting, create another directory which we will call 'build_dir'.



Do:



  cd build_dir

  cmake source_dir

  make install



The "make install" step may require administrator privileges.



You can adjust the installation destination (the "prefix")

by passing the -DCMAKE_INSTALL_PREFIX=myprefix option to cmake, as is

explained in the message that cmake prints at the end.