Steps to install and run lpsolve on a Mac

There are several ways to install lpsolve on a Mac. Here is one way.

1. Go to the Sourceforge page for lpsolve.
2. Click the big green Download button and, when prompted, save the downloaded file to your Downloads folder.

   This will download the latest source code for lpsolve to your machine. It does not take long: lpsolve is a small program. The file will have a name like lp_solve_5.5.2.11_source.tar.gz. (The 5.5.2.11 is a version; you might get a new version.)

3. In Finder, navigate to your Downloads folder and double-click on the downloaded file.

   This will decompress the file and expand it into a set of folders. You should then see a folder named something like lp_solve_5.5 in your Downloads folder, together with the downloaded .gz file.

4. Open the application Terminal on your machine.

   You may find it in the Utilities folder inside your applications folder.

5. In Terminal, navigate to your Downloads folder. To do this, in the Terminal window, type the following commands, each followed by the enter key:

   cd
   cd Downloads
   cd lp_solve_5.5
   cd lp_solve
   sh ccc.osx
   

This last command runs the shell script ccc.osx to set up lpsolve. You may see some warnings; you can probably ignore them.
However, if you see an error like "xcrun: error: invalid active developer path", this most likely indicates that the lpsolve install script is looking for xcode command-line tools on your machine and cannot find them. In this case, try adding the xcode tools with this command:
xcode-select --install
It will take a few moments to this do installation. Then open a new terminal window, and try step #5 above again.
These commands will create a sub-folder, bin containing the executable lp_solve (it may be in a further sub-folder, named something like osx64.)
6. Navigate to the subfolder containing lp_solve by executing these commands in Terminal:

   cd bin
   cd osx64
   ls
   

   This last command, ls, will list the files in this folder: you should see lp_solve listed. This is the executable application.

7. To test lpsolve and see that you've installed it, you will need a test lp file. You can use test.lp. Use Finder to put this file in the same folder with lp_solve.
8. In Terminal, run lp_solve on this file with the command

   ./lp_solve test.lp
   

   lpsolve will run and give you the following result:

   Value of objective function: 4.61764706
   
   Actual values of the variables:
   x                         3.58824
   y                         1.02941
   

   This indicates that these values of x and y, the minimum sum x+y, 4.61764706, is achieved with x=3.58824 and y=1.02941 (approximately) while satisfying the specified constraints.

9. Congratulations! You have succesfully installed lpsolve!

Additional notes

• After the above installation lp_solve now lives in that one location deep down in your Downloads folder. You can move lp_solve anywhere you want to, so you might want to move it somewhere else (I periodically delete everything in my Downloads folder so it's not a good permanent home for anything. I recommend moving it somewhere else, somewhere safe. Let's say that you put it in a folder called lpsolve that you create in your Applications folder. Then what you can do is create an alias so that, in Terminal, you can run lp_solve from any location.

  To create an alias, you will need to edit your bash profile. In your home directory, there may be a file like .bash_profile (if it is not there, you can create it). Note that this is a "hidden" file (since it starts with a dot), so you may not see it in Finder. You will need to make hidden files visible; depending on your OS version, there are various ways to do this. In Terminal, the command

  ls -a

  will list all files in the current directory, including hidden ones. If you don't see .bash_profile, you can create one. Either edit .bash_profile and add this line:

  alias lp_solve='/Applications/lpsolve/lp_solve'
  

  or create a new file, .bash_profile, containing that line.

  Save the file, then restart Terminal and you will be able to execute lp_solve from any folder (which will be useful since you will likely create multiple folder for the different LPs we'll be looking at in the course.) The command to execture lp_solve will look like

  lp_solve test.lp
  

  where test.lp is the text file containing the LP you want to solve. Note that the "./" is not needed if you make the alias (the ./ indicates to the operating system that you want to run the application lp_solve that is right there in the current directory. With the alias, the operating system is told where to find the application.)
  
  Alternatively, in Terminal, the command

  echo 'alias lp_solve="/Applications/lpsolve/lp_solve"' >> .bash-profile
  

  will add the alias to .bash_profile without using an editor (or create it if the file does not already exist). This also will not require you to make hidden files visible in Finder.