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Convert a permutation vector to its corresponding matrix.
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| """ | |
| Given a permutation vector, return the corresponding permutation matrix such that | |
| `A[p,:] = P*A`. | |
| See [Wikipedia](https://en.wikipedia.org/wiki/Permutation_matrix#Definition). | |
| """ | |
| function pvec2mat(p) | |
| n = length(p) | |
| P = zeros(n,n) | |
| for i in 1:n | |
| P[i,:] = ej(n,p[i]) | |
| end | |
| return sparse(P) | |
| end |
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