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Question: ConditionNumber (floating-point case)

Question: ConditionNumber (floating-point case)

fbackelj 271 Maple
linear-algebra norm
December 10 2015
2

How does one explain this? 

> 

restart;
> 

A := Matrix( 3, 3, [ 1, 1, 1, 1, 0, 0, 1, -1, 1 ] );
LinearAlgebra[ConditionNumber]( A );
linalg[cond]( A );

A := Matrix(3, 3, {(1, 1) = 1, (1, 2) = 1, (1, 3) = 1, (2, 1) = 1, (2, 2) = 0, (2, 3) = 0, (3, 1) = 1, (3, 2) = -1, (3, 3) = 1})

  

6

  

6

  
> 

B := evalf( A );
LinearAlgebra[ConditionNumber]( B );
linalg[cond]( B );

B := Matrix(3, 3, {(1, 1) = 1., (1, 2) = 1., (1, 3) = 1., (2, 1) = 1., (2, 2) = 0., (2, 3) = 0., (3, 1) = 1., (3, 2) = -1., (3, 3) = 1.})

  

3.000000000

  

6.000000000

  


Is this not a valid way for creating a floating-point matrix?
Otherwise, how do I explain the wrong result here?

-- Regards,

Franky

 
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