В Thu, 3 Jan 2008 17:58:59 +0800 "Alex Rufon" <[EMAIL PROTECTED]> пишет:
> ... > > Nick. Just tell us what you think of doing. Maybe we can help. There > are a lot of brilliant people here on the list and maybe we can help > thing move along for you. ;) Thanks a lot. I have two goals. The first one adds up to doing a giant system of linear equations. The matrix A in the equation Y=A*X is rather sparse, but large. The size of matrix A is 100 million to 100 million, however, the matrix row will only have around 100 cells with the values different from zero. The description of this matrix is located in the file with 3 columns. The first two columns contain the cell's coordinates, the third column contains the value. That is, the file contains 10 billion rows. I haven't decided yet what format is better to store the data in one file. It can be either fixed length rows, or CSV. What is better from the J viewpoint ? That said, the task consists of the following: 1) read the file and generate the matrix 2) do a system of linear equations 3) save the result In a word, it's simple , but for the newbie in J it's hard to define the best way for now. Say, the process of "Connection matrix" generation described here http://www.jsoftware.com/help/dictionary/samp20.htm doesn't seem quite optimal to me for the above task solution. The second task is connected to the factor analysis, however, there are less data here. So, I believe upon the first task solution I'll acquire the experience needed to solve the second one. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
