**Matrix: Davis/FX_March2010**

Description: MATLAB FileExchange, keyword analysis (March 2010)

(bipartite graph drawing) |

Matrix properties | |

number of rows | 1,319 |

number of columns | 9,498 |

nonzeros | 301,899 |

structural full rank? | no |

structural rank | 1,140 |

# of blocks from dmperm | 72 |

# strongly connected comp. | 163 |

explicit zero entries | 0 |

nonzero pattern symmetry | 0% |

numeric value symmetry | 0% |

type | integer |

structure | rectangular |

Cholesky candidate? | no |

positive definite? | no |

author | T. Davis |

editor | T. Davis |

date | 2010 |

kind | term/document graph |

2D/3D problem? | no |

Additional fields | size and type |

key | cell 1319-by-1 |

id | full 9498-by-1 |

inbook | full 1-by-1 |

Notes:

Analysis of the MATLAB FileExchange, March 2010 For the 8th Edition of the MATLAB Primer (published by CRC Press) I wrote a script that downloaded and parsed all 9489 submissions to the MATLAB File Exchange (as of March 12, 2010, 8am), at: http://www.mathworks.com/matlabcentral/fileexchange/ . Each submission was parsed to determine how many times each of 1319 keywords appears. The list of keywords to search for was obtained by parsing the MATLAB Help documentation. In the primary matrix (Problem.A), the entry A(i,j) is the nubmer of times that the ith keyword appears in the jth "file" (each of the submissions to the MATLAB File Exchange is called a "file", although each submission often consists of more than one actual file). Problem.aux.key{i} is the ith keyword, and Problem.aux.id(j) is the MATLAB File ID corresponding to the jth column of the matrix A. The first 454 rows of the A matrix correspond to the 454 functions or keywords that appear in the "MATLAB Top 500" list of most- frequently used functions, keywords, and operators in the 8th Edition of the MATLAB Primer. The remaining are operators (+ - / * . etc) to round out the "Top 500" (these do not appear in the Problem.A matrix since parsing them proved difficult). Note that some editorial adjustments were made to the Top 500. In particular, deprecated functions were removed. Some of the trigonometric functions are rarely used, but all of them were included in the "Top 500" to make a complete set. You can visualize this with semilogy(sum(A,2)). The rows of A are mostly sorted in decreasing row-sum, except for rows 430 to 470 or so. This matrix was constructed in March 2010 by Tim Davis and added to the collection in July 2012; Tim Davis is solely responsible for this matrix. It was not submitted by or authorized by The MathWorks, Inc, but since the File Exchange is now under a BSD license, this is included in the collection as a legitimate derivative work.

SVD-based statistics: | |

norm(A) | 134672 |

min(svd(A)) | 0 |

cond(A) | Inf |

rank(A) | 1,137 |

sprank(A)-rank(A) | 3 |

null space dimension | 182 |

full numerical rank? | no |

singular value gap | 8.56195e+11 |

singular values (MAT file): | click here |

SVD method used: | s = svd (full (R)) ; where [~,R,E] = spqr (A') with droptol of zero |

status: | ok |

For a description of the statistics displayed above, click here.

*Maintained by Tim Davis, last updated 12-Mar-2014.Matrix pictures by cspy, a MATLAB function in the CSparse package.
Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.
*