Linear Algebra

http://d2l.ai/chapter_preliminaries/linear-algebra.html

We can access the scalar element aijaij of a matrix AA in :eqref: eq_matrix_def by specifying the indices for the row (ii) and column (jj), such as [A]ij[A]ij. When the scalar elements of a matrix AA, such as in :eqref: eq_matrix_def

what is :eqref: eq_matrix_def here?

Hey @gpk2000, thanks for pointing out the typo. The equation doesn’t render properly, it should mean to be equation 2.3.2.

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Thanks. Now it’s fixed. See comments in https://github.com/d2l-ai/d2l-en/issues/1448

Here are a few norm examples for the MXNet folks:

Frobenius Norms
[nav] In [51]: np.linalg.norm(np.arange(24))
Out[51]: array(65.75713)

[nav] In [52]: np.sqrt(np.sum(np.arange(24)**2))
Out[52]: array(65.757126)

L1 Norm
[ins] In [50]: np.linalg.norm(np.arange(24), ord=1)
Out[50]: array(276.)

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I don’t know where I am supposed to start thinking from to answer question 7, can someone give me some pointers?