matrix/coloring.py

This example looks at coloring methods for sparse matrices

View output (PDF) | source (python)

See also
casadi::Sparsity::uni_coloring();
casadi::Sparsity::uni_coloring
Sparsity uni_coloring(const Sparsity &AT=Sparsity(), casadi_int cutoff=std::numeric_limits< casadi_int >::max()) const
Perform a unidirectional coloring: A greedy distance-2 coloring algorithm.
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24 from casadi import *
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28 def color(A):
29  print("="*80)
30  print("Original:")
31  print(repr(DM(A,1)))
32  print("Colored: ")
33  print(repr(DM(A.uni_coloring(),1)))
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35 A = Sparsity.diag(5)
36 color(A)
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40 color(Sparsity.dense(5,10))
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46 color(A+Sparsity.triplet(5,5,[0],[4]))
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50 color(A+Sparsity.triplet(5,5,[4],[0]))
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54 color(A+Sparsity.triplet(5,5,[0]*5,list(range(5))))
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59 color(A+Sparsity.triplet(5,5,list(range(5)),[0]*5))
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65 def color(A):
66  print("="*80)
67  print("Original:")
68  print(repr(DM(A,1)))
69  print("Star colored: ")
70  print(repr(DM(A.star_coloring(1),1)))
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72 color(A)
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76 color(Sparsity.dense(5,5))
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80 color(A+Sparsity.triplet(5,5,[0]*5,list(range(5)))+Sparsity.triplet(5,5,list(range(5)),[0]*5))
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87 A = DM([[1,1,0,0,0,0],[1,1,1,0,1,1],[0,1,1,1,0,0],[0,0,1,1,0,1],[0,1,0,0,1,0],[0,1,0,1,0,1]])
88 A = sparsify(A)
89 color(A.sparsity())