The coprimeness tests illustrated in Example 4.3 can be carried out automatically by using the functions LeftCoprime and RightCoprime. LeftCoprime[system] | test if the matrices d and n in the left matrix-fraction system are relatively left prime | LeftCoprime[m{1}, m2, var]
RightCoprime[system]
RightCoprime[m{1}, m2, var] | test if the two polynomial matrices m{1} and m{2}, in the variable var, are relatively left prime
test if the matrices n and d in the right matrix-fraction system are relatively right prime
test if the two polynomial matrices m{1} and m{2}, in the variable var, are relatively right prime |
Testing the coprimeness. Make sure the application is loaded. Here are the matrices N(s) and D(s) of a right matrix-fraction model of a system. Out[3]= | ![](HTMLImages/LeftCoprime.en/LeftCoprime.en_i_3.gif) |
Out[5]= | ![](HTMLImages/LeftCoprime.en/LeftCoprime.en_i_5.gif) |
This constructs a block matrix . Out[7]= | ![](HTMLImages/LeftCoprime.en/LeftCoprime.en_i_7.gif) |
This is its Smith form. Out[9]= | ![](HTMLImages/LeftCoprime.en/LeftCoprime.en_i_9.gif) |
Since the leading 2 × 2 block of the Smith form is equal to the identity matrix I2, the two polynomial matrices describing the right matrix-fraction model are relatively right prime, or coprime, and hence no lower-order version exists that would create the same transfer-function matrix. Here is the same result obtained at once using the function RightCoprime. Out[11]= | ![](HTMLImages/LeftCoprime.en/LeftCoprime.en_i_11.gif) |
Here is the corresponding right matrix-fraction object. Out[13]= | ![](HTMLImages/LeftCoprime.en/LeftCoprime.en_i_13.gif) |
You can also apply the function RightCoprime directly to the matrix-fraction object. Out[15]= | ![](HTMLImages/LeftCoprime.en/LeftCoprime.en_i_15.gif) |
Here is a LeftMatrixFraction object. Out[17]= | ![](HTMLImages/LeftCoprime.en/LeftCoprime.en_i_17.gif) |
You can equally apply the function LeftCoprime directly to the matrix-fraction object. Out[19]= | ![](HTMLImages/LeftCoprime.en/LeftCoprime.en_i_19.gif) |
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