Barton Willis <willisb at unk.edu> writes:
> (%i8) m : genmatrix(lambda([i,j], 1.0/(i + j - 1)), 5,5)$ (%i9) b :
> genmatrix(lambda([i,j], 1.0),5,1)$
>
> (%i10) linsolve_by_lu(m,b, 'floatfield); (%o10) [matrix
> ([5.000000000079979],[-120.0000000015632],[630.0000000069121],[-1120.000000010609],
> [630.0000000052486]),1.0690256198668838*10^+7]
Does linsolve_by_lu solve it using LU decomposition? I can't find the
description of the function. I am using Maxima 5.13
Does linsolve use Gaussian Elimination to solve system of linear
equations?
So, is it possible to force linsolve to use floating point arithmetic
calculations with limited precision?
Sorry for replying also to you personally Barton.
> The last entry of the list in %o10 is an upper bound for the matrix
> condition number. A better value for the condition number is
>
> (%i14) mat_cond(m,1), ratprint : false; (%o14) 943655.9999980911
>
> Barton
>
> -----maxima-bounces at math.utexas.edu wrote: -----
>
>>Is?it?possible?to?force?Maxima?to?behave?more?like?Matlab?with?regard?to
>>internal?arithmetic?precision.?I?am?trying?to?solve?a?system?of?linear
>>equations?with?linsolve.?Maxima?converts?the?numbers?to?rational?numbers
>>and?does?the?gaussian?elimination?with?this?rational?numbers?and?gives
>>me?the?exact?results.?Can?I?force?Maxima?to?do?the?internal?arithmetic
>>with?limited?floating?point?precision??I?want?to?get?results?similar?to
>>Matlab.?What?I?am?saying?is:?Maxima?gives?too?perfect?solution?:)
>
>
>
--
"For, contrary to the unreasoned opinion of the ignorant, the choice of
a system of numeration is mere matter of convention."
- Blaise Pascal (1623-1662)