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Re: Complexity explosion in linear solve


carlos at colorado.edu wrote:

>> Try Method->"OneStepRowReduction" (without quotes, if in versions < 6) and
--------------------------------------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>> see if that helps.

<snip>

>> Daniel Lichtblau
>> Wolfram Research
> 
> When I tried that option under version 5.2 for Mac OS X,
> the expression returns unevaluated.  I could not find documentation
> for it; what does it do?

<snip>

Have you tried without quotes? Without quotes surrounding the value for 
the option, the following works fine on my system.

In[1]:=
$Version
mat = {{1, 2, 3}, {1, 3, 4}};
b = {5, 8};
x = LinearSolve[mat, b, Method -> OneStepRowReduction]

Out[1]=
5.2 for Microsoft Windows (June 20, 2005)

Out[4]=
{-1, 3, 0}

(More information can be found in Michael Trott's _The Mathematica 
GuideBook for Programming_, p 826: "Method is an option for the commands 
LinearSolve, Inverse, RowReduce (to be treated soon), and NullSpace. It 
defines the internal algorithm to be used in the computation. Default: 
Automatic. Admissible: DivisionFreeRowReduction or CofactorExpansion or 
OneStepRowReduction.")

HTH
-- 
Jean-Marc


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