brandones

1;  % script file

function res = deleted_pivot(M, i, j)
    % Calculates the deleted pivot of matrix M at row i, column j
    % as described by Greg Kuperberg in "Kasteleyn cokernels"

    % X = the jth column of M with element i removed
    X = [M(:,j)(1:i-1); M(:,j)(i+1:end)];
    % Yt = the ith row of M with element j removed
    Yt = [M(i,:)(1:j-1), M(i,:)(j+1:end)];

brandones

#!/usr/bin/python
#
# Placed at /usr/local/bin/python
# Expects pylint executable at /usr/bin/pylint
#

import os
import sys

def get_python_exec():

brandones

import networkx as nx
import numpy
import scipy.io
import scipy.linalg
import scipy.sparse.linalg
from scipy.sparse.linalg.eigen.arpack.arpack import ArpackNoConvergence


def reduce_from_matlab(mat_path, output_dim):
    mat = scipy.io.loadmat(mat_path)

brandones

function X = graph_pca(A, k)
  % A: the adjacency matrix of a graph
  % k: the number of dimensions to reduce to
  %
  % Calculates the ECTD-preserving PCA of the graph given by A.
  % See http://outobox.cs.umn.edu/PCA_on_a_Graph.pdf for background.
  L = diag(sum(A)) - A;
  Lp = pinv(L);
  [U, E] = eigs(Lp, k);
  X = E.^(1/2) * U';