matrix/scc.py

This example looks at scc

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See also
casadi::Sparsity::scc();
casadi::diagcat();
casadi::Sparsity::scc
casadi_int scc(std::vector< casadi_int > &index, std::vector< casadi_int > &offset) const
Find the strongly connected components of the bigraph defined by the sparsity pattern.
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24 from casadi import *
25 import numpy
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29 A = diagcat(1,DM([[2,3],[3,4]]),DM([[5,6,7],[6,8,9],[7,9,10]]),11)
30 print(A)
31 A.sparsity().spy()
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33 numpy.random.seed(2)
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37 perm = list(numpy.random.permutation(list(range(A.size1()))))
38 AP = A[perm,perm]
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40 print(AP)
41 AP.sparsity().spy()
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45 n,p,r = AP.sparsity().scc()
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47 APrestored = AP[p,p]
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49 print(APrestored)
50 APrestored.sparsity().spy()
51 print("# blocks: ", n)
52 print("block boundaries: ", r[:n])