NullSpace[m], why different result for symbolic vs numerical matrix?
- To: mathgroup at smc.vnet.net
- Subject: [mg59206] NullSpace[m], why different result for symbolic vs numerical matrix?
- From: "Nasser Abbasi" <nma at 12000.org>
- Date: Tue, 2 Aug 2005 00:42:28 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
hello, This 5.2 on windows.
The help for NullSpace function says:
"NullSpace works on both numerical and symbolic matrices. "
But why do I get different answer if matrix A is numeric vs symbolic?
What Am I missing?
Both answers are correct in the sense that A times each of null
vectors produced does give 0.
------------
Remove["Global`*"]
A = {{0, 1, 1, 2}, {1, 2, 3, 4}, {2, 0, 2, 0}};
m1 = NullSpace[A]
m2 = NullSpace[N[A, 16]]
Out[190]= {{0, -2, 0, 1}, {-1, -1, 1, 0}}
Out[191]=
{{0.5286741846941267165032578206`16., -0.4493204281752718232493645376`16.,
-0.5286741846941267165032578206`16.,
0.488997306434699269876311179`16.},
{-0.4183886482487962269364866589`16., -0.78504329244074722971820122`16.,
0.4183886482487962269364866589`16.,
0.1833273220959755013908572806`16.}}
-------------
thanks
Nasser