Comments | ultimatepsi: Ask LJ: freeware data tools

ultimatepsi

Ask LJ: freeware data tools

Jul 02, 2009 15:16

I have a large set of numerical data is a comma-separated values text file that I want to a) plot, b) find maxima and minimum of, c) apply functions to every point of. This is the kind of thing that I used to use Matlab for, but I don't have access to Matlab anymore and it isn't cheap. Excel or OpenOffice Calc can do these tasks, but I don't have ( Read more... )

ask lj, data analysis, math, software, work

Comments 13

londo July 2 2009, 19:53:44 UTC

For plotting, Excel is probably the way to go, especially if you only have 5000 rows.

For the other stuff - have you considered some sort of database? sqlite is nicely lightweight.

ultimatepsi July 2 2009, 20:08:12 UTC

I'm going to have more rows at some point. Not being designed for large n is the problem with OpenOffice.

Will sqlite let me do math operations?

londo July 2 2009, 20:13:23 UTC

Probably. There's nothing wrong with "SELECT column, sqrt(column) FROM table" in SQL syntax, but sqlite doesn't support everything.

MySQL may have better support for more math functions, but will take a little while to install, as opposed to sqlite, which is so small and easy to install that the Perl database interface driver for it comes with a complete copy of sqlite itself just in case.

sirroxton July 2 2009, 19:58:48 UTC

The god-grade answer is R, but that's... hard. I'd really have to recommend getting a copy of Excel somehow.

ultimatepsi July 2 2009, 20:30:45 UTC

R seems a lot like MatLab, but it also doesn't like reading comma-separated value. WTF, that's a standard format.

sirroxton July 2 2009, 21:04:22 UTC

Why do you say that? R has "read.csv".

ultimatepsi July 2 2009, 21:13:39 UTC

Ah, so apparently it's only the documentation that is lacking. *sigh*

Thread 5

dariusk July 2 2009, 20:12:40 UTC

You can use Octave. It's the open source version of MATLAB -- it's even compatible with 95% of M-script.

http://www.gnu.org/software/octave/

fiddledragon July 2 2009, 20:29:02 UTC

If you need something that is actually Matlab at some point, Brandeis has it on some of the library computers, so long as you don't mind transporting your data back and forth.

randysmith July 2 2009, 20:56:58 UTC

I haven't played with it as much as I'd like, but the combination of Numpy, Scipy, and matplotlib (all python packages) would probably let you do what you want (presuming you don't mind hacking in python). I'm somewhat excited about matplotlib as a plotting tool, but still need to get my feet (and knees, and etc.) thoroughly wet.

You could use OpenOffice for an open source version of excel, but I have no idea how good their plotting support is.

coriolinus July 3 2009, 03:09:25 UTC

This would also be my first approach to your problem as described.