MATLAB POLYSPACE RELEASE NOTES Manuel d'utilisateur télécharger pdf (Page 49)

More About Matrices and Arrays

Scalar Expansio

Matrices and sca

lars can be combined in several different ways. For example,

ascalarissubtr

acted from a matrix by subtracting it from each element. The

average value of

the elements in our magic square is 8.5, so

B=A-8.5

forms a matrix w

hose column sums are zero:

7.5 -5.5 -6.5 4.5

-3.5 1.5 2.5 -0.5

0.5 -2.5 -1.5 3.5

-4.5 6.5 5.5 -7.5

sum(B)

ans =

0000

With scalar expan

sion, MATLAB assigns a s pe c if ied scala r to all i n dices in a

range. For exampl

B(1:2,2:3) = 0

zeroes out a port

ion o f

7.5 0 0 4.5

-3.5 0 0 -0.5

0.5 -2.5 -1.5 3.5

-4.5 6.5 5.5 -7.5

Logical Subscrip

ting

The logical vecto

rs created from logical and relational operations can be us ed

to reference suba

rrays. Suppose

X is an ordinary matrix and L is a matri x of

thesamesizetha

t is the result of some logical operation. Then

X(L) specifies

the elements of

where the elements of L are nonzero.

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MATLAB POLYSPACE RELEASE NOTES Manuel d'utilisateur Page 49