/*
* 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 javax.vecmath.Point3d;
import org.openscience.cdk.annotations.TestClass;
import org.openscience.cdk.annotations.TestMethod;
import org.openscience.cdk.config.IsotopeFactory;
import org.openscience.cdk.exception.CDKException;
import org.openscience.cdk.geometry.GeometryTools;
import org.openscience.cdk.interfaces.IAtom;
import org.openscience.cdk.interfaces.IAtomContainer;
import org.openscience.cdk.interfaces.IMolecularFormula;
import org.openscience.cdk.qsar.DescriptorSpecification;
import org.openscience.cdk.qsar.DescriptorValue;
import org.openscience.cdk.qsar.IMolecularDescriptor;
import org.openscience.cdk.qsar.result.DoubleArrayResult;
import org.openscience.cdk.qsar.result.DoubleArrayResultType;
import org.openscience.cdk.qsar.result.IDescriptorResult;
import org.openscience.cdk.tools.ILoggingTool;
import org.openscience.cdk.tools.LoggingToolFactory;
import org.openscience.cdk.tools.manipulator.MolecularFormulaManipulator;
import Jama.EigenvalueDecomposition;
import Jama.Matrix;
/**
* A descriptor that calculates the moment of inertia and radius of gyration.
* Moment of inertia (MI) values characterize the mass distribution of a molecule.
* Related to the MI values, ratios of the MI values along the three principal axes
* are also well know modeling variables. This descriptor calculates the MI values
* along the X, Y and Z axes as well as the ratio's X/Y, X/Z and Y/Z. Finally it also
* calculates the radius of gyration of the molecule.
* <p/>
* The descriptor generates 7 values in the following order
* <ul>
* <li>MOMI-X - MI along X axis
* <li>MOMI-Y - MI along Y axis
* <li>MOMI-Z - MI along Z axis
* <li>MOMI-XY - X/Y
* <li>MOMI-XZ - X/Z
* <li>MOMI-YZ Y/Z
* <li>MOMI-R - Radius of gyration
* </ul>
* One important aspect of the algorithm is that if the eigenvalues of the MI tensor
* are below 1e-3, then the ratio's are set to a default of 1000.
* <p/>
* <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>
*
* @author Rajarshi Guha
* @cdk.created 2005-02-07
* @cdk.builddepends Jama-1.0.2.jar
* @cdk.depends Jama-1.0.2.jar
* @cdk.module qsarmolecular
* @cdk.githash
* @cdk.set qsar-descriptors
* @cdk.dictref qsar-descriptors:momentOfInertia
* @cdk.keyword moment of inertia
*/
@TestClass("org.openscience.cdk.qsar.descriptors.molecular.MomentOfInertiaDescriptorTest")
public class MomentOfInertiaDescriptor implements IMolecularDescriptor {
private static ILoggingTool logger =
LoggingToolFactory.createLoggingTool(MomentOfInertiaDescriptor.class);
private static final String[] names = {
"MOMI-X", "MOMI-Y", "MOMI-Z",
"MOMI-XY", "MOMI-XZ", "MOMI-YZ", "MOMI-R"
};
@TestMethod("testGetSpecification")
public DescriptorSpecification getSpecification() {
return new DescriptorSpecification(
"http://www.blueobelisk.org/ontologies/chemoinformatics-algorithms/#momentOfInertia",
this.getClass().getName(),
"$Id$",
"The Chemistry Development Kit");
}
/**
* Sets the parameters attribute of the MomentOfInertiaDescriptor object.
*
* @param params The new parameters value
* @throws CDKException Description of the Exception
* @see #getParameters
*/
@TestMethod("testSetParameters_arrayObject")
public void setParameters(Object[] params) throws CDKException {
// no parameters for this descriptor
}
/**
* Gets the parameters attribute of the MomentOfInertiaDescriptor object.
*
* @return The parameters value
* @see #setParameters
*/
@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 MomentOfInertiaDescriptor object.
*
* @return The parameterNames value
*/
@TestMethod("testGetParameterNames")
public String[] getParameterNames() {
// no param names to return
return (null);
}
/**
* Gets the parameterType attribute of the MomentOfInertiaDescriptor object.
*
* @param name Description of the Parameter
* @return The parameterType value
*/
@TestMethod("testGetParameterType_String")
public Object getParameterType(String name) {
return (null);
}
private DescriptorValue getDummyDescriptorValue(Exception e) {
int ndesc = getDescriptorNames().length;
DoubleArrayResult results = new DoubleArrayResult(ndesc);
for (int i = 0; i < ndesc; i++) results.add(Double.NaN);
return new DescriptorValue(getSpecification(), getParameterNames(),
getParameters(), results, getDescriptorNames(), e);
}
/**
* Calculates the 3 MI's, 3 ration and the R_gyr value.
*
* The molecule should have hydrogens
*
* @param container Parameter is the atom container.
* @return An ArrayList containing 7 elements in the order described above
*/
@TestMethod("testCalculate_IAtomContainer")
public DescriptorValue calculate(IAtomContainer container) {
if (!GeometryTools.has3DCoordinates(container))
return getDummyDescriptorValue(new CDKException("Molecule must have 3D coordinates"));
IAtomContainer clone;
IsotopeFactory factory;
try {
clone = (IAtomContainer)container.clone();
factory = IsotopeFactory.getInstance(container.getBuilder());
factory.configureAtoms(clone);
} catch (Exception e) {
logger.debug(e);
return getDummyDescriptorValue(e);
}
DoubleArrayResult retval = new DoubleArrayResult(7);
double ccf = 1.000138;
double eps = 1e-5;
double[][] imat = new double[3][3];
Point3d centerOfMass = GeometryTools.get3DCentreOfMass(clone);
double xdif;
double ydif;
double zdif;
double xsq;
double ysq;
double zsq;
for (int i = 0; i < clone.getAtomCount(); i++) {
IAtom currentAtom = clone.getAtom(i);
double mass = factory.getMajorIsotope(currentAtom.getSymbol()).getExactMass();
xdif = currentAtom.getPoint3d().x - centerOfMass.x;
ydif = currentAtom.getPoint3d().y - centerOfMass.y;
zdif = currentAtom.getPoint3d().z - centerOfMass.z;
xsq = xdif * xdif;
ysq = ydif * ydif;
zsq = zdif * zdif;
imat[0][0] += mass * (ysq + zsq);
imat[1][1] += mass * (xsq + zsq);
imat[2][2] += mass * (xsq + ysq);
imat[1][0] += -1 * mass * ydif * xdif;
imat[0][1] = imat[1][0];
imat[2][0] += -1 * mass * xdif * zdif;
imat[0][2] = imat[2][0];
imat[2][1] += -1 * mass * ydif * zdif;
imat[1][2] = imat[2][1];
}
// diagonalize the MI tensor
Matrix tmp = new Matrix(imat);
EigenvalueDecomposition eigenDecomp = tmp.eig();
double[] eval = eigenDecomp.getRealEigenvalues();
retval.add(eval[2]);
retval.add(eval[1]);
retval.add(eval[0]);
double etmp = eval[0];
eval[0] = eval[2];
eval[2] = etmp;
if (Math.abs(eval[1]) > 1e-3) retval.add(eval[0] / eval[1]);
else retval.add(1000);
if (Math.abs(eval[2]) > 1e-3) {
retval.add(eval[0] / eval[2]);
retval.add(eval[1] / eval[2]);
} else {
retval.add(1000);
retval.add(1000);
}
// finally get the radius of gyration
double pri;
IMolecularFormula formula = MolecularFormulaManipulator.getMolecularFormula(clone);
if (Math.abs(eval[2]) > eps) pri = Math.pow(eval[0] * eval[1] * eval[2], 1.0 / 3.0);
else pri = Math.sqrt(eval[0] * ccf / MolecularFormulaManipulator.getTotalExactMass(formula));
retval.add(Math.sqrt(Math.PI * 2 * pri * ccf / MolecularFormulaManipulator.getTotalExactMass(formula)));
return new DescriptorValue(getSpecification(), getParameterNames(), getParameters(),
retval, getDescriptorNames());
}
/**
* 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 DoubleArrayResultType(7);
}
}