Java 使用迭代值增量的趋势分析
我们已将iReport配置为生成以下图表: 实际数据点为蓝色,趋势线为绿色。这些问题包括:Java 使用迭代值增量的趋势分析,java,algorithm,ireport,data-analysis,Java,Algorithm,Ireport,Data Analysis,我们已将iReport配置为生成以下图表: 实际数据点为蓝色,趋势线为绿色。这些问题包括: 趋势线的数据点太多 趋势线不遵循贝塞尔曲线(样条曲线) 问题的根源在于incrementer类。递增器以迭代方式提供数据点。似乎没有办法获得这组数据。计算趋势线的代码如下所示: import java.math.BigDecimal; import net.sf.jasperreports.engine.fill.*; /** * Used by an iReport variable to i
- 趋势线的数据点太多
- 趋势线不遵循贝塞尔曲线(样条曲线)
import java.math.BigDecimal;
import net.sf.jasperreports.engine.fill.*;
/**
* Used by an iReport variable to increment its average.
*/
public class MovingAverageIncrementer
implements JRIncrementer {
private BigDecimal average;
private int incr = 0;
/**
* Instantiated by the MovingAverageIncrementerFactory class.
*/
public MovingAverageIncrementer() {
}
/**
* Returns the newly incremented value, which is calculated by averaging
* the previous value from the previous call to this method.
*
* @param jrFillVariable Unused.
* @param object New data point to average.
* @param abstractValueProvider Unused.
* @return The newly incremented value.
*/
public Object increment( JRFillVariable jrFillVariable, Object object,
AbstractValueProvider abstractValueProvider ) {
BigDecimal value = new BigDecimal( ( ( Number )object ).doubleValue() );
// Average every 10 data points
//
if( incr % 10 == 0 ) {
setAverage( ( value.add( getAverage() ).doubleValue() / 2.0 ) );
}
incr++;
return getAverage();
}
/**
* Changes the value that is the moving average.
* @param average The new moving average value.
*/
private void setAverage( BigDecimal average ) {
this.average = average;
}
/**
* Returns the current moving average average.
* @return Value used for plotting on a report.
*/
protected BigDecimal getAverage() {
if( this.average == null ) {
this.average = new BigDecimal( 0 );
}
return this.average;
}
/** Helper method. */
private void setAverage( double d ) {
setAverage( new BigDecimal( d ) );
}
}
如何创建更平滑、更准确的趋势线表示?这取决于所测量项目的行为。这是以可以建模的方式移动(或改变)的东西吗 如果项目预计不会改变,那么您的趋势应该是整个样本集的基本平均值,而不仅仅是过去两次测量。你可以用贝叶斯定理得到这个。运行平均值可以使用简单的公式递增计算 Mtn1=(Mtn*N+x)/(N+1) 其中x是时间t+1的测量值,Mtn1是时间t+1的平均值,Mtn是时间t的平均值,N是时间t的测量次数 如果您正在测量的项目以某种基本方程可以预测的方式波动,那么您可以使用a根据以前(最近)的测量结果和建模预测行为的方程提供下一点的最佳估计
作为一个起点,Wikipedia上的条目和Kalman Filters将很有帮助。结果图像
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;
import net.sf.jasperreports.engine.fill.AbstractValueProvider;
import net.sf.jasperreports.engine.fill.JRFillVariable;
import net.sf.jasperreports.engine.fill.JRIncrementer;
/**
* Used by an iReport variable to increment its average.
*/
public class RunningAverageIncrementer
implements JRIncrementer {
/** Default number of tallies. */
private static final int DEFAULT_TALLIES = 128;
/** Number of tallies within the sliding window. */
private static final int DEFAULT_SLIDING_WINDOW_SIZE = 30;
/** Stores a sliding window of values. */
private List<Double> values = new ArrayList<Double>( DEFAULT_TALLIES );
/**
* Instantiated by the RunningAverageIncrementerFactory class.
*/
public RunningAverageIncrementer() {
}
/**
* Calculates the average of previously known values.
* @return The average of the list of values returned by getValues().
*/
private double calculateAverage() {
double result = 0.0;
List<Double> values = getValues();
for( Double d: getValues() ) {
result += d.doubleValue();
}
return result / values.size();
}
/**
* Called each time a new value to be averaged is received.
* @param value The new value to include for the average.
*/
private void recordValue( Double value ) {
List<Double> values = getValues();
// Throw out old values that should no longer influence the trend.
//
if( values.size() > getSlidingWindowSize() ) {
values.remove( 0 );
}
this.values.add( value );
}
private List<Double> getValues() {
return values;
}
private int getIterations() {
return getValues().size();
}
/**
* Returns the newly incremented value, which is calculated by averaging
* the previous value from the previous call to this method.
*
* @param jrFillVariable Unused.
* @param tally New data point to average.
* @param abstractValueProvider Unused.
* @return The newly incremented value.
*/
public Object increment( JRFillVariable jrFillVariable, Object tally,
AbstractValueProvider abstractValueProvider ) {
double value = ((Number)tally).doubleValue();
recordValue( value );
double previousAverage = calculateAverage();
double newAverage =
((value - previousAverage) / (getIterations() + 1)) + previousAverage;
return new BigDecimal( newAverage );
}
protected int getSlidingWindowSize() {
return DEFAULT_SLIDING_WINDOW_SIZE;
}
}
结果仍然不完整,但它清楚地显示了比问题中更好的趋势线
计算
缺少两个关键组件:
- 滑动窗。由
双倍
值组成的
列表,不能超过给定的大小
- 计算。接受答案的变体(少调用一次
):getIterations()
((value-previousAverage)/(getIterations()+1))+previousAverage
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;
import net.sf.jasperreports.engine.fill.AbstractValueProvider;
import net.sf.jasperreports.engine.fill.JRFillVariable;
import net.sf.jasperreports.engine.fill.JRIncrementer;
/**
* Used by an iReport variable to increment its average.
*/
public class RunningAverageIncrementer
implements JRIncrementer {
/** Default number of tallies. */
private static final int DEFAULT_TALLIES = 128;
/** Number of tallies within the sliding window. */
private static final int DEFAULT_SLIDING_WINDOW_SIZE = 30;
/** Stores a sliding window of values. */
private List<Double> values = new ArrayList<Double>( DEFAULT_TALLIES );
/**
* Instantiated by the RunningAverageIncrementerFactory class.
*/
public RunningAverageIncrementer() {
}
/**
* Calculates the average of previously known values.
* @return The average of the list of values returned by getValues().
*/
private double calculateAverage() {
double result = 0.0;
List<Double> values = getValues();
for( Double d: getValues() ) {
result += d.doubleValue();
}
return result / values.size();
}
/**
* Called each time a new value to be averaged is received.
* @param value The new value to include for the average.
*/
private void recordValue( Double value ) {
List<Double> values = getValues();
// Throw out old values that should no longer influence the trend.
//
if( values.size() > getSlidingWindowSize() ) {
values.remove( 0 );
}
this.values.add( value );
}
private List<Double> getValues() {
return values;
}
private int getIterations() {
return getValues().size();
}
/**
* Returns the newly incremented value, which is calculated by averaging
* the previous value from the previous call to this method.
*
* @param jrFillVariable Unused.
* @param tally New data point to average.
* @param abstractValueProvider Unused.
* @return The newly incremented value.
*/
public Object increment( JRFillVariable jrFillVariable, Object tally,
AbstractValueProvider abstractValueProvider ) {
double value = ((Number)tally).doubleValue();
recordValue( value );
double previousAverage = calculateAverage();
double newAverage =
((value - previousAverage) / (getIterations() + 1)) + previousAverage;
return new BigDecimal( newAverage );
}
protected int getSlidingWindowSize() {
return DEFAULT_SLIDING_WINDOW_SIZE;
}
}
import java.math.BigDecimal;
导入java.util.ArrayList;
导入java.util.List;
导入net.sf.jasperreports.engine.fill.AbstractValueProvider;
导入net.sf.jasperreports.engine.fill.JRFillVariable;
导入net.sf.jasperreports.engine.fill.jrrincrementer;
/**
*iReport变量用于增加其平均值。
*/
公共类RunningAverageIncrementer
实现JR增量器{
/**默认计数数*/
私有静态最终整数默认计数=128;
/**滑动窗口内的计数数*/
私有静态最终整数默认值滑动窗口大小=30;
/**存储值的滑动窗口*/
私有列表值=新的ArrayList(默认值);
/**
*由RunningAverageIncrementerFactory类实例化。
*/
公共运行平均增量器(){
}
/**
*计算以前已知值的平均值。
*@return getValues()返回的值列表的平均值。
*/
私有双计算{
双结果=0.0;
列表值=getValues();
for(双d:getValues()){
结果+=d.双值();
}
返回结果/值。size();
}
/**
*每次接收到要平均的新值时调用。
*@param value要包含在平均值中的新值。
*/
私有无效记录值(双倍值){
列表值=getValues();
//抛弃那些不应该再影响趋势的旧价值观。
//
如果(values.size()>GetSlidingWindowsSize()){
值。删除(0);
}
这个.values.add(值);
}
私有列表getValues(){
返回值;
}
私有int getIterations(){
返回getValues().size();
}
/**
*返回新增加的值,该值通过平均值计算
*此方法的上一次调用的上一个值。
*
*@param jrFillVariable未使用。
*@param将新数据点计数为平均值。
*@param abstractValueProvider未使用。
*@返回新增加的值。
*/
公共对象增量(JRFillVariable、JRFillVariable、对象计数、,
AbstractValueProvider(AbstractValueProvider){
double value=((数字)计数).double value();
记录值(value);
双倍上一次平均值=calculateAverage();
双新平均=
((value-previousAverage)/(getIterations()+1))+previousAverage;
返回新的BigDecimal(newAverage);
}
受保护的int GetSlidingWindowsSize(){
返回默认的滑动窗口大小;
}
}