/*
* Copyright (C) 2004-2007 Rajarshi Guha <rajarshi@users.sourceforge.net>
*
* Contact: cdk-devel@lists.sourceforge.net
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package org.openscience.cdk.qsar.descriptors.molecular;
import org.openscience.cdk.annotations.TestClass;
import org.openscience.cdk.annotations.TestMethod;
import org.openscience.cdk.exception.CDKException;
import org.openscience.cdk.graph.PathTools;
import org.openscience.cdk.graph.matrix.AdjacencyMatrix;
import org.openscience.cdk.interfaces.IAtomContainer;
import org.openscience.cdk.qsar.DescriptorSpecification;
import org.openscience.cdk.qsar.DescriptorValue;
import org.openscience.cdk.qsar.IMolecularDescriptor;
import org.openscience.cdk.qsar.result.IDescriptorResult;
import org.openscience.cdk.qsar.result.IntegerResult;
import org.openscience.cdk.tools.manipulator.AtomContainerManipulator;
/**
* A topological descriptor combining distance and adjacency information.
* This descriptor is described by Sharma et al. {@cdk.cite SHA97} and has been shown
* to correlate well with a number of physical properties. The descriptor is also reported to
* have good discriminatory ability.
* <p>
* The eccentric connectivity index for a hydrogen supressed molecular graph is given by the
* expression
* <center>
* \xi^{c} = \sum_{i = 1}{n} E(i) V(i)
* </center>
* where E(i) is the eccentricity of the i<sup>th</sup> atom (path length from the
* i<sup>th</sup> atom to the atom farthest from it) and V(i) is the vertex degree of the
* i<sup>th</sup> atom.
*
* <p>This descriptor uses these parameters:
* <table border="1">
* <tr>
* <td>Name</td>
* <td>Default</td>
* <td>Description</td>
* </tr>
* <tr>
* <td></td>
* <td></td>
* <td>no parameters</td>
* </tr>
* </table>
*
* Returns a single value with name <i>ECCEN</i>
* @author Rajarshi Guha
* @cdk.created 2005-03-19
* @cdk.module qsarmolecular
* @cdk.githash
* @cdk.set qsar-descriptors
* @cdk.dictref qsar-descriptors:eccentricConnectivityIndex
*/
@TestClass("org.openscience.cdk.qsar.descriptors.molecular.EccentricConnectivityIndexDescriptorTest")
public class EccentricConnectivityIndexDescriptor implements IMolecularDescriptor {
private static final String[] names = {"ECCEN"};
public EccentricConnectivityIndexDescriptor() {}
@TestMethod("testGetSpecification")
public DescriptorSpecification getSpecification() {
return new DescriptorSpecification(
"http://www.blueobelisk.org/ontologies/chemoinformatics-algorithms/#eccentricConnectivityIndex",
this.getClass().getName(),
"$Id$",
"The Chemistry Development Kit");
}
/**
* Sets the parameters attribute of the EccentricConnectivityIndexDescriptor object
*
*@param params The new parameters value
*@exception CDKException Description of the Exception
*/
@TestMethod("testSetParameters_arrayObject")
public void setParameters(Object[] params) throws CDKException {
// no parameters for this descriptor
}
/**
* Gets the parameters attribute of the EccentricConnectivityIndexDescriptor object
*
*@return The parameters value
*/
@TestMethod("testGetParameters")
public Object[] getParameters() {
// no parameters to return
return(null);
}
@TestMethod(value="testNamesConsistency")
public String[] getDescriptorNames() {
return names;
}
/**
* Gets the parameterNames attribute of the EccentricConnectivityIndexDescriptor object
*
*@return The parameterNames value
*/
@TestMethod("testGetParameterNames")
public String[] getParameterNames() {
// no param names to return
return(null);
}
/**
* Gets the parameterType attribute of the EccentricConnectivityIndexDescriptor object
*
*@param name Description of the Parameter
*@return The parameterType value
*/
@TestMethod("testGetParameterType_String")
public Object getParameterType(String name) {
return (null);
}
/**
* Calculates the eccentric connectivity
*
*@param container Parameter is the atom container.
*@return An IntegerResult value representing the eccentric connectivity index
*/
@TestMethod("testCalculate_IAtomContainer")
public DescriptorValue calculate(IAtomContainer container) {
IAtomContainer local = AtomContainerManipulator.removeHydrogens(container);
int natom = local.getAtomCount();
int[][] admat = AdjacencyMatrix.getMatrix(local);
int[][] distmat = PathTools.computeFloydAPSP(admat);
int eccenindex = 0;
for (int i = 0; i < natom; i++) {
int max = -1;
for (int j = 0; j < natom; j++) {
if (distmat[i][j] > max) max = distmat[i][j];
}
int degree = local.getConnectedBondsCount(i);
eccenindex += max * degree;
}
IntegerResult retval = new IntegerResult(eccenindex);
return new DescriptorValue(getSpecification(), getParameterNames(), getParameters(),
retval, getDescriptorNames(), null);
}
/**
* Returns the specific type of the DescriptorResult object.
* <p/>
* The return value from this method really indicates what type of result will
* be obtained from the {@link org.openscience.cdk.qsar.DescriptorValue} object. Note that the same result
* can be achieved by interrogating the {@link org.openscience.cdk.qsar.DescriptorValue} object; this method
* allows you to do the same thing, without actually calculating the descriptor.
*
* @return an object that implements the {@link org.openscience.cdk.qsar.result.IDescriptorResult} interface indicating
* the actual type of values returned by the descriptor in the {@link org.openscience.cdk.qsar.DescriptorValue} object
*/
@TestMethod("testGetDescriptorResultType")
public IDescriptorResult getDescriptorResultType() {
return new IntegerResult(1);
}
}