graph-theory

How do I run graphx with Python / pyspark?

by

You should look at GraphFrames (https://github.com/graphframes/graphframes), which wraps GraphX algorithms under the DataFrames API and it provides Python interface. Here is a quick example from https://graphframes.github.io/graphframes/docs/_site/quick-start.html, with slight modification so that it works first start pyspark with the graphframes pkg loaded pyspark –packages graphframes:graphframes:0.1.0-spark1.6 python code: from graphframes import * # Create a Vertex DataFrame … Read more

Spectral Clustering a graph in python

by

Without much experience with Spectral-clustering and just going by the docs (skip to the end for the results!): Code: import numpy as np import networkx as nx from sklearn.cluster import SpectralClustering from sklearn import metrics np.random.seed(1) # Get your mentioned graph G = nx.karate_club_graph() # Get ground-truth: club-labels -> transform to 0/1 np-array # (possible … Read more

Register allocation and spilling, the easy way?

by

I’ve used a greedy approach in a JVM allocator once, which worked pretty well. Basically start at the top of a basic block with all values stored on the stack. Then just scan the instructions forward, maintaining a list of registers which contain a value, and whether the value is dirty (needs to be written … Read more

How to detect if adding an edge to a directed graph results in a cycle?

by

If I understood your question correctly, then a new edge (u,v) is only inserted if there was no path from v to u before (i.e., if (u,v) does not create a cycle). Thus, your graph is always a DAG (directed acyclic graph). Using Tarjan’s Algorithm to detect strongly connected components (http://en.wikipedia.org/wiki/Tarjan%27s_strongly_connected_components_algorithm) sounds like an overkill … Read more

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)