/*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Arithmetic.java
* Copyright (C) 2008-2012 University of Waikato, Hamilton, New Zealand
*
*/
package weka.core.pmml;
import java.util.ArrayList;
import weka.core.Attribute;
import weka.core.Utils;
/**
* Built-in function for min, max, sum, avg, log10,
* ln, sqrt, abs, exp, pow, threshold, floor, ceil and round.
*
* @author Mark Hall (mhall{[at]}pentaho{[dot]}com)
* @version $Revision 1.0 $
*/
public class BuiltInMath extends Function {
/**
* For serialization
*/
private static final long serialVersionUID = -8092338695602573652L;
/**
* Enum for the math functions.
*/
enum MathFunc {
MIN ("min") {
double eval(double[] args) {
return args[Utils.minIndex(args)];
}
boolean legalNumParams(int num) {
return (num > 0);
}
String[] getParameterNames() {
return null; // unbounded number of parameters
}
},
MAX ("max") {
double eval(double[] args) {
return args[Utils.maxIndex(args)];
}
boolean legalNumParams(int num) {
return (num > 0);
}
String[] getParameterNames() {
return null; // unbounded number of parameters
}
},
SUM ("sum") {
double eval(double[] args) {
return Utils.sum(args);
}
boolean legalNumParams(int num) {
return (num > 0);
}
String[] getParameterNames() {
return null; // unbounded number of parameters
}
},
AVG ("avg") {
double eval(double[] args) {
return Utils.mean(args);
}
boolean legalNumParams(int num) {
return (num > 0);
}
String[] getParameterNames() {
return null; // unbounded number of parameters
}
},
LOG10 ("log10") {
double eval(double[] args) {
return Math.log10(args[0]);
}
boolean legalNumParams(int num) {
return (num == 1);
}
String[] getParameterNames() {
return new String[] {"A"};
}
},
LN ("ln") {
double eval(double[] args) {
return Math.log(args[0]);
}
boolean legalNumParams(int num) {
return (num == 1);
}
String[] getParameterNames() {
return new String[] {"A"};
}
},
SQRT ("sqrt") {
double eval(double[] args) {
return Math.sqrt(args[0]);
}
boolean legalNumParams(int num) {
return (num == 1);
}
String[] getParameterNames() {
return new String[] {"A"};
}
},
ABS ("abs") {
double eval(double[] args) {
return Math.abs(args[0]);
}
boolean legalNumParams(int num) {
return (num == 1);
}
String[] getParameterNames() {
return new String[] {"A"};
}
},
EXP ("exp") {
double eval(double[] args) {
return Math.exp(args[0]);
}
boolean legalNumParams(int num) {
return (num == 1);
}
String[] getParameterNames() {
return new String[] {"A"};
}
},
POW ("pow") {
double eval(double[] args) {
return Math.pow(args[0], args[1]);
}
boolean legalNumParams(int num) {
return (num == 2);
}
String[] getParameterNames() {
return new String[] {"A", "B"};
}
},
THRESHOLD ("threshold") {
double eval(double[] args) {
if (args[0] > args[1]) {
return 1.0;
} else {
return 0.0;
}
}
boolean legalNumParams(int num) {
return (num == 2);
}
String[] getParameterNames() {
return new String[] {"A", "B"};
}
},
FLOOR ("floor") {
double eval(double[] args) {
return Math.floor(args[0]);
}
boolean legalNumParams(int num) {
return (num == 1);
}
String[] getParameterNames() {
return new String[] {"A"};
}
},
CEIL ("ceil") {
double eval(double[] args) {
return Math.ceil(args[0]);
}
boolean legalNumParams(int num) {
return (num == 1);
}
String[] getParameterNames() {
return new String[] {"A"};
}
},
ROUND ("round") {
double eval(double[] args) {
return Math.round(args[0]);
}
boolean legalNumParams(int num) {
return (num == 1);
}
String[] getParameterNames() {
return new String[] {"A"};
}
};
abstract double eval(double[] args);
abstract boolean legalNumParams(int num);
abstract String[] getParameterNames();
private final String m_stringVal;
MathFunc(String funcName) {
m_stringVal = funcName;
}
public String toString() {
return m_stringVal;
}
}
/** The function to apply */
protected MathFunc m_func = MathFunc.ABS;
/**
* Construct a new built-in pmml Math function.
* @param func the math function to use
*/
public BuiltInMath(MathFunc func) {
m_func = func;
m_functionName = m_func.toString();
}
/**
* Set the structure of the parameters that are expected as input by
* this function. This must be called before getOutputDef() is called.
*
* @param paramDefs the structure of the input parameters
* @throws Exception if the number or types of parameters are not acceptable by
* this function
*/
public void setParameterDefs(ArrayList<Attribute> paramDefs) throws Exception {
m_parameterDefs = paramDefs;
if (!m_func.legalNumParams(m_parameterDefs.size())) {
throw new Exception("[BuiltInMath] illegal number of parameters for function: "
+ m_functionName);
}
}
/**
* Get the structure of the result produced by this function.
* Subclasses must implement.
*
* @return the structure of the result produced by this function.
*/
public Attribute getOutputDef() {
return new Attribute("BuiltInMathResult:" + m_func.toString());
}
/**
* Returns an array of the names of the parameters expected
* as input by this function. May return null if the function
* can accept an unbounded number of arguments.
*
* @return an array of the parameter names (or null if the function
* can accept any number of arguments).
*/
public String[] getParameterNames() {
return m_func.getParameterNames();
}
/**
* Get the result of applying this function.
*
* @param incoming the arguments to this function (supplied in order to match that
* of the parameter definitions
* @return the result of applying this function. When the optype is
* categorical or ordinal, an index into the values of the output definition
* is returned.
* @throws Exception if there is a problem computing the result of this function
*/
public double getResult(double[] incoming) throws Exception {
if (m_parameterDefs == null) {
throw new Exception("[BuiltInMath] incoming parameter structure has not been set");
}
if (!m_func.legalNumParams(incoming.length)) {
throw new Exception("[BuiltInMath] wrong number of parameters!");
}
double result = m_func.eval(incoming);
return result;
}
public String toString() {
String result = m_func.toString() + "(";
for (int i = 0; i < m_parameterDefs.size(); i++) {
result += m_parameterDefs.get(i).name();
if (i != m_parameterDefs.size() - 1) {
result += ", ";
} else {
result += ")";
}
}
return result;
}
}