Mr. Roman Pearce

## 1683 Reputation

19 years, 242 days
CECM/SFU
Research Associate

I am a research associate at Simon Fraser University and a member of the Computer Algebra Group at the CECM.

## Solving Sparse Linear Systems in Maple...

Maple

What is the largest linear system that Maple can solve? You might be surprised to find out. In this article we present strategies for solving sparse linear systems over the rationals. An example implementation is provided, but first we present a bit of background. Sparse linear systems arise naturally from problems in mathematics, science, and engineering. Typically many quantities are related, but because of an underlying structure only a small subset of the elements appear in most equations. Consider networks, finite element models, structural analysis problems, and linear programming problems.

## Improvements to Maple 11 Groebner...

Maple 11

Maple 11 has been out for a while now so hopefully people have it. I thought I would write a short post detailing some of what was done in the area of Groebner bases. If you run the examples in Maple 10 and Maple 11, I would appreciate it if you could post the times and the specifications of your computer.

## spam report button...

I would like a button attached to comments to report posts as spam. To make this useful (as opposed to unproductive) you would need a program to construct a daily list of all spam posts, so that the moderators are not inundated with spam reports (thereby producing more spam).

## bookmarks for help...

I find that when I'm working on something new I consistently end up reading the same set of help pages over and over. The "History" option in the help system has been very useful to me, but I would like to see a "Bookmarks" option added to Maple's help system as well.

## Turn loops into seqs with assign...

Maple
Consider the following three problems: 1) given a list [a,b,c,d,e], return the list [a=1,b=2,c=3,d=4,e=5] 2) given a nested list [a, [b, [c, [d, [e]]]]] return the list [a,b,c,d,e] 3) given an integer in base 10, compute it's base b representation First I will show you what not to do:
```L := [a,b,c,d,e];
M := [];
for i from 1 to nops(L) do
M := [op(M), L[i]=i];
end do;
```
Building up lists (and sets) incrementally is quadratic time, because each iteration of the loop allocates linear storage to hold the new list. The standard solution is a loop with a temporary variable, assigning to a table:
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