
	Where results make sense

Topic: Incidence matrix

Related Topics

Biadjacency matrix

Adjacency matrix

Algebraic graph theory

Spectral graph theory

Connected graph

Graph theory

Identity matrix

Null space

Cycle space

Adjacency list

Spanning tree (mathematics)

Bipartite graph

Graph drawing

Cograph

Vector space

In the News (Tue 17 Nov 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	Incidence matrix - Wikipedia, the free encyclopedia
		The incidence matrix of a signed graph is a generalization of the oriented incidence matrix.
		The column of an oriented incidence matrix that corresponds to a loop is all zero, unless the graph is signed and the loop is negative; then the column is all zero except for ±2 in the row of its incident vertex.
		In this case the incidence matrix is also a biadjacency matrix of the Levi graph of the structure.
	en.wikipedia.org /wiki/Incidence_matrix (721 words)

	Adjacency matrix - Wikipedia, the free encyclopedia
		In the special case of a finite, simple graph, the adjacency matrix is a (0,1)-matrix with zeros on its diagonal.
		The relationship between a graph and its adjacency matrix is studied in spectral graph theory.
		The adjacency matrix of an undirected graph is symmetric, and therefore has a complete set of eigenvalues and orthogonal eigenvector basis.
	en.wikipedia.org /wiki/Adjacency_matrix (812 words)

	Graph theory - Open Encyclopedia (Site not responding. Last check: 2007-10-08)
		In general, there are four ways to represent a graph in a computer system: The incidence list representation, the incidence matrix representation, adjacency list representation, and the adjacency matrix representation.
		Incidence matrix - This representation uses a matrix of M edges by N vertices.
		Adjacency matrix - there is an N by N matrix, where N is the total number of vertices in the graph.
	open-encyclopedia.com /Graph_theory (881 words)

	Matrices Help Relationships
		Label the rows and columns of matrix by E, J, and P. Place a 1 in a cell of the matrix provided the row label of the cell is related to the column label of that cell.
		To see why, set up the incidence matrix for the relationship between faces and edges of a deltahedron by "is a face containing the edge".
		Hence the sum of all the ones in the incidence matrix is 3F, where F is the number of faces in the given deltahedron.
	www.cut-the-knot.org /blue/relation.shtml (738 words)

	Incidence matrix -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-10-08)
		The incidence matrix is related to the (additional info and facts about adjacency matrix) adjacency matrix of its line graphgraph by the following theorem:
		where is the adjacency matrix of the line graph of, is incidence matrix, and is the (A scalar matrix in which all of the diagonal elements are unity) identity matrix of dimension q.
		In this case the incidence matrix is also a (additional info and facts about biadjacency matrix) biadjacency matrix of the (additional info and facts about Levi graph) Levi graph of the structure.
	www.absoluteastronomy.com /encyclopedia/i/in/incidence_matrix.htm (129 words)

	Eigenvalues of an incidence matrix
		With matrix theory we will show that there are only a small number of values for n for which there exists a network of flights between n cities satisfying the given conditions.
		Let A be the incidence matrix for the relationship "there is a direct flight between", with the rows and columns of A labelled by the cities.
		The matrix J is a very simple matrix so we know what its eigenvalues are, namely 0 n-1 times and n once.
	www.cut-the-knot.org /blue/airline.shtml (1238 words)

	UCF Computer Science Colloquium (Site not responding. Last check: 2007-10-08)
		A matrix with the property that the determinant of each of its sub-square matrices is 1, -1 or 0 is said to be totally unimodular.
		In his second paper, the concept of the incidence matrix of a graph was introduced indirectly as coefficients of Kirchhoff current law equations, indicating incidence relationships between nodes and edges of a circuit whose connection structure is the graph.
		The total unimodularity of the incidence matrix, the fundamental loop matrix, and the fundamental cutest matrix of a graph is known to have played an important role implicitly in the development of the circuit theory as well as the flow and/or tension theory since Kirchhoff.
	longwood.cs.ucf.edu /csdept/colloq/2002-03/03-03-11.html (404 words)

	The Working Basis Matrix
		Most of the columns of this matrix are columns of the problem's node-arc incidence matrix.
		B (n x k) are the node-arc incidence matrix columns of the nontree arcs.
		Because the C matrix consists of columns of the constraint coefficient matrix, the maintenance of C from iteration to iteration simply entails changing information specifying which columns of the constraint coefficient matrix compose C.
	www.uni.edu /sasdoc/ormp/chap4/sect49.htm (464 words)

	[No title] (Site not responding. Last check: 2007-10-08)
		Prove that each of the rows of the nodal incidence matrix is orthogonal to each of the rows of the loop incidence matrix.
		It follows that there will be zeros in all of the positions of the row of the A matrix that correspond to nonzero entries in the row of the B matrix.
		Then their entries will both be positive in the row of the nodal incidence matrix, A. On the other hand, upon considering any loop orientation, then one of these branches must be directed along the orientation of the loop and the other must be directed against it.
	www.eecs.lehigh.edu /~ece420/hw7_sol.html (348 words)

	Assignment 0 (Site not responding. Last check: 2007-10-08)
		The incidence matrix for the sample strings used above is shown below.
		For example, the diagonal sequence from position (7, 1) to position (11,5) in the matrix above indicates that the substring from character 7 to character 11 in string 1 matches the one from character 1 to character 5 in string 2.
		An obvious and simple algorithm for matching two strings, given their incidence matrix, is to look for the longest sequence of trues along one of the main diagonals.
	www.cs.toronto.edu /~dianeh/148/97s/a0/handout/a0.html (1505 words)

	A procedure for generating incidence matrices
		Finally, as an advanced example, we show how to compute an incidence matrix from a list of edges in a network.
		The directed edges can be given as a list of pairs [i,j] where i is the beginning node of the edge and j is the ending node.
		Thus, from a list of these pairs, we should be able to generate the incidence matrix.
	www.math.okstate.edu /~wrightd/5593/maple-intro/node19.html (266 words)

	Abstract Definitions and Examples of Graphs
		The ideas of adjacency and incidence can be used to come up with different ways of representing a graph.
		You could also try making an incidence matrix and trying to re-construct a graph from the information contained in the matrix.
		For example, notice that all the entries on the main diagonal of the matrix are zero.
	www.math.lsa.umich.edu /mmss/coursesONLINE/graph/graph2 (1796 words)

	REPORT BRIEF (Site not responding. Last check: 2007-10-08)
		Once the system functional requirements model is built and the relationships between functional elements are obtained, an incidence (interaction) matrix for system functions is constructed (see Figure 2).
		A function-function incidence matrix can be restructured using the clustering algorithm developed in this research to obtain the clusters in the incidence matrix (see Figure 3).
		From the modularity matrix in Figure 3 the functional modules for the system are obtained (see Figure 4).
	www.engin.umd.umich.edu /ceep/tech_day/2002/reports/IMSEReport10 (770 words)

	R: Generate system matrix for LDEs (Site not responding. Last check: 2007-10-08)
		Generate the system matrix for the linear differential equations determined by a compartment model.
		Given a description of the system and a vector of parameter values this function returns the system matrix.
		This function is intended for use in a general system for solving compartment models, as described in Bates and Watts (1988).
	math.furman.edu /~dcs/courses/math47/library/nlme/html/LDEsysMat.html (132 words)

	Covariances (JMSL)
		More observations are being deleted from the output covariance matrix than were originally entered (the corresponding row,column of the incidence matrix is less than zero).
		Indicates correlation matrix except for the diagonal elements which are the standard deviations
		The corresponding row,column of the incidence matrix is less than zero.
	www.vni.com /products/imsl/jmsl/v20/api/com/imsl/stat/Covariances.html (662 words)

	Graph theory Article, Graphtheory Information (Site not responding. Last check: 2007-10-08)
		This canalso apply to directed graphs by ensuring the first vertex be defined as the source or destination while the second should bedefined as the opposite.
		This can sometimesresult in "overkill" in an undirected graph as vertex 3 may be in the list for node 2, then node 2 must be in the list for node3.
		Thisrepresentation is easier to find all the nodes which are connected to a single node, since these are explicitly listed.
	www.anoca.org /graphs/edges/graph_theory.html (837 words)

	CS267: Notes for Lecture 23, April 9, 1999
		Note the similarity between the Laplacian graph of the mesh, and the matrix for the discrete Poisson equation, introduced in Lecture 13.
		Given any n-by-n sparse symmetric matrix A, Lanczos computes a k-by-k symmetric tridiagonal matrix T, whose eigenvalues are good approximations of the eigenvalues of T, and whose eigenvectors can be used to get approximate eigenvectors of A. Building T requires k matrix-vector multiplications with A; this is typically the most expensive part of the algorithm.
		In the matrix K, this means that there are few nonzero entries far from the diagonal, because these would correspond to an edge from a v(i) to a v(j) widely separated in the sorted list.
	www.cs.berkeley.edu /~demmel/cs267/lecture20/lecture20.html (7067 words)

	IBM Research \| People \| Alan Hoffman (Site not responding. Last check: 2007-10-08)
		The eigenvalues of the adjacency matrix of a graph, Proc.
		Estimation of eigenvalues of a matrix and the theory of linear inequalities, Proc.
		On the distance matrix of a graph, Journal of Graph Theory 1:85-88 (1977) (with R. Graham And H. Hosoya).
	www.research.ibm.com /people/a/ajh (2931 words)

	Homework 4.4
		Draw the graph represented by each incidence matrix.
		Input: Matrix A the nxn adjacency matrix of a simple graph G. Output: Total number of degrees in the graph.
		Input: Matrix A the nxn adjacency matrix of a graph G. Output: True if the graph contains a loop and false if not.
	www.omegamath.com /Discrete/hwk4.4.html (452 words)

	Matlog Reference
		x n matrix of predecessor indices, where P(i,j) is the index of the predecessor to node 'j' on the path from 's(i)' to 'j',where P(i,i) = 0 and P(i,j) = NaN is 'j' not on path to 's(i)' (use PRED2PATH to convert P to paths) = path from 's' to 't', if s
		X = randX(P,n) Generates n x d matrix X of n random d-dimensional NF locations, where each dimension is within the min and max EF locations of P (if m = 1, then each X(i,:) = P).
		A = tri2adj(T) T = n x 3 matrix, where each row defines indices for one of n triangles A = (sparse) m x m adjacency matrix, m is the maximum index value Converts set of triangles defined by X and Y vector indices into A. Useful for ploting results from DELAUNAY triangulation using GPLOT.
	www.ie.ncsu.edu /kay/matlog/MatlogRef.htm (3281 words)

	PlanetMath:
		ill-conditioned (in matrix condition number) owned by stevecheng
		incidence relation (in incidence geometry) owned by CWoo
		irreducible matrix (in reducible matrix) owned by mps
	planetmath.org /encyclopedia/I (1524 words)

	Homework 4.4
		Hint: Look at the adjacency matrix for problems 2 and 4.
		Below is an adjacency matrix A for a graph G. Use matrices, (A + A
		Use your graphing calculator or other matrix program.
	www.omegamath.com /Discrete/cp4.4.html (546 words)

	Incidence matrix
		In mathematics, the incidence matrix of a graph G is a p × q matrix where p and q are the number of vertices and edges respectively, such that if the vertex and edge are incident and 0 otherwise.
		where and are the adjacency matrix and incidence matrix respectively and is the identity matrix of dimension q.
		Talking much about oneself can also be a means to conceal oneself.
	www.brainyencyclopedia.com /encyclopedia/i/in/incidence_matrix.html (132 words)

	Peter Olver's Matlab Programs
		graph.m - finds incidence matrix and plots a graph
		incidence.m - computes incidence matrix from edge matrix
		cgraph.m - finds incidence matrix and plots complete graph
	www.math.umn.edu /~olver/matlab.html (497 words)

Try your search on: Qwika (all wikis)