Structural Health Monitoring Using Smart Sensors - ideals ...

10 0 Imote2
Matlab 0
10 -20
0 10 20 30 40 50
10 0 |0|/|0|
10 -20
0 10 20 30 40 50
Order of eigenvalues
Eigenvalue
magnitude
Eigenvalue
error ratio
(a)
10 5 Imote2
Matlab 0
10 -5
0 10 20 30 40 50
10 -10 |0|/|0|
10 -20
0 10 20 30 40 50
Order of eigenvalues
Eigenvalue
magnitude
Eigenvalue
error ratio
Figure 7.4. Complex eigensolver accuracy check on 50 x 50 matrix (eigenvalues): (a)
smaller eigenvalues; and (b) larger eigenvalues.
(b)
1
2 x10-15 Order of eigenvalues
1-MAC
0.8
0.6
0.4
0.2
1-MAC
1
0
-1
0
0 10 20 30 40 50
Order of eigenvalues
(a)
-2
0 10 20 30 40 50
Figure 7.5. Complex eigensolver accuracy check on 50 x 50 matrix (eigenvector): (a)
smaller eigenvalues; and (b) larger eigenvalues.
(b)
The matrix size for which an eigenanalysis can be performed is limited by available
memory. The size of a complex double precision matrix is twice as large as that of real
double precision matrix. Double precision eigenvalues and eigenvectors of an n n
complex matrix occupies n + n B of memory. The eigensolver uses another n n
matrix internally, resulting in a need for n + n B memory in total; the size of
memory needed to keep other small internal variables are not counted. When n = 89, the
RAM space occupied by these matrices exceeds the size of the 256 kB of on-board RAM
on the Imote2.
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