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I have my matrix $h$ of size $2N\times 2N$ in this form

$$h=\begin{pmatrix} a & b \\ c & d \end{pmatrix} $$ where $a,b,c,d$ are smaller matrices which i don't know. Is there any simple way to get this matrix? $$\begin{pmatrix} a &0& b&0 \\ 0 &a& 0&b\\ c &0& d&0 \\ 0 &c& 0&d\\ \end{pmatrix} $$

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  • $\begingroup$ Check out KroneckerProduct $\endgroup$
    – chuy
    Commented Jun 25, 2019 at 14:41

1 Answer 1

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MatrixForm[h = {{a, b}, {c, d}}]

$ h=\left( \begin{array}{cc} a & b \\ c & d \\ \end{array} \right)$

KroneckerProduct[h, IdentityMatrix@2] // MatrixForm

$ \left( \begin{array}{cccc} a & 0 & b & 0 \\ 0 & a & 0 & b \\ c & 0 & d & 0 \\ 0 & c & 0 & d \\ \end{array} \right)$

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  • $\begingroup$ thank you,it is exactly what i wanted! $\endgroup$
    – Alexander Nikolaenko
    Commented Jun 25, 2019 at 14:53

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