mdiggory 2003/06/16 13:42:25
Modified: math/src/java/org/apache/commons/math/stat
UnivariateImpl.java
Log:
This house-cleaning improves UnivariateImpl, in a number of ways.
1.) insertValue is abolished and its contents are now in addValue
2.) UnivariateImpl now extends AbstractStoredUnivariate to deligate to
those methods directly for calculating statistics when storage is active, all
methods
deligate to AbstractStoreUniv when the DoubleArray is no longer null. This also
means
that a majority of the StoreUnivariate interface is now implemented in Univariate to
provide
deligates when storage is active, and to throw runtime exceptions when its not (this
at least until
we establish rolling implementations for those methods). We should consider
consolidating the
StoreUnivariate interface into the Univariate interface
3.) Calculations in addValue have been reorganized, only calculations for
the storageless solution are now present in this class. otherwise the value is
added/Rolling to the Double array when appropriate.
I'm satisfied that it passes all Unit tests.
Revision Changes Path
1.6 +383 -347
jakarta-commons-sandbox/math/src/java/org/apache/commons/math/stat/UnivariateImpl.java
Index: UnivariateImpl.java
===================================================================
RCS file:
/home/cvs/jakarta-commons-sandbox/math/src/java/org/apache/commons/math/stat/UnivariateImpl.java,v
retrieving revision 1.5
retrieving revision 1.6
diff -u -r1.5 -r1.6
--- UnivariateImpl.java 16 Jun 2003 14:29:30 -0000 1.5
+++ UnivariateImpl.java 16 Jun 2003 20:42:24 -0000 1.6
@@ -74,349 +74,385 @@
* @version $Revision$ $Date$
*
*/
-public class UnivariateImpl implements Univariate, Serializable {
-
- /** hold the window size **/
- private int windowSize = Univariate.INFINITE_WINDOW;
-
- /** Just in case the windowSize is not infinite, we need to
- * keep an array to remember values 0 to N
- */
- private DoubleArray doubleArray;
-
- /** count of values that have been added */
- private int n = 0;
-
- /** min of values that have been added */
- private double min = Double.MAX_VALUE;
-
- /** max of values that have been added */
- private double max = Double.MIN_VALUE;
-
- /** product of values that have been added */
- private double product = Double.NaN;
-
- /** mean of values that have been added */
- private double mean = Double.NaN ;
-
- /** running ( variance * (n - 1) ) of values that have been added */
- private double pre_variance = Double.NaN ;
-
- /** variance of values that have been added */
- private double variance = Double.NaN ;
-
- /** running sum of values that have been added */
- private double sum = 0.0;
-
- /** running sum of squares that have been added */
- private double sumsq = 0.0;
-
- /** running sum of 3rd powers that have been added */
- private double sumCube = 0.0;
-
- /** running sum of 4th powers that have been added */
- private double sumQuad = 0.0;
-
- /** Creates new univariate with an infinite window */
- public UnivariateImpl() {
- clear();
- }
-
- /** Creates a new univariate with a fixed window **/
- public UnivariateImpl(int window) {
- windowSize = window;
- doubleArray = new FixedDoubleArray( window );
- }
-
- /**
- * @see org.apache.commons.math.stat.Univariate#addValue(double)
- */
- public void addValue(double v) {
- insertValue(v);
- }
-
- /**
- * @see org.apache.commons.math.stat.Univariate#getMean()
- */
- public double getMean() {
- return mean ;
- }
-
- /**
- * @see org.apache.commons.math.stat.Univariate#getGeometricMean()
- */
- public double getGeometricMean() {
- if ((product <= 0.0) || (n == 0)) {
- return Double.NaN;
- } else {
- return Math.pow(product,( 1.0 / (double) n ) );
- }
- }
-
- /**
- * @see org.apache.commons.math.stat.Univariate#getProduct()
- */
- public double getProduct() {
- return product;
- }
-
- /**
- * @see org.apache.commons.math.stat.Univariate#getStandardDeviation()
- */
- public double getStandardDeviation() {
- double variance = getVariance();
-
- if ((variance == 0.0) || (variance == Double.NaN)) {
- return variance;
- } else {
- return Math.sqrt(variance);
- }
- }
-
- /**
- * Returns the variance of the values that have been added via West's
- * algorithm as described by
- * <a href="http://doi.acm.org/10.1145/359146.359152";>Chan, T. F. and
- * J. G. Lewis 1979, <i>Communications of the ACM</i>,
- * vol. 22 no. 9, pp. 526-531.</a>.
- *
- * @return The variance of a set of values. Double.NaN is returned for
- * an empty set of values and 0.0 is returned for a <= 1 value set.
- */
- public double getVariance() {
- return variance ;
- }
-
- /**
- * Returns the skewness of the values that have been added as described by
- * <a href="http://mathworld.wolfram.com/k-Statistic.html";>Equation (6) for
k-Statistics</a>.
- *
- * @return The skew of a set of values. Double.NaN is returned for
- * an empty set of values and 0.0 is returned for a <= 2 value set.
- */
- public double getSkewness() {
-
- if( n < 1) return Double.NaN;
- if( n <= 2 ) return 0.0;
-
- return ( 2 * Math.pow(sum, 3) - 3 * sum * sumsq + ((double) (n * n)) *
sumCube ) /
- ( (double) (n * (n - 1) * (n - 2)) ) ;
- }
-
- /**
- * Returns the kurtosis of the values that have been added as described by
- * <a href="http://mathworld.wolfram.com/k-Statistic.html";>Equation (7) for
k-Statistics</a>.
- *
- * @return The kurtosis of a set of values. Double.NaN is returned for
- * an empty set of values and 0.0 is returned for a <= 3 value set.
- */
- public double getKurtosis() {
-
- if( n < 1) return Double.NaN;
- if( n <= 3 ) return 0.0;
-
- double x1 = -6 * Math.pow(sum, 4);
- double x2 = 12 * ((double) n) * Math.pow(sum, 2) * sumsq;
- double x3 = -3 * ((double) (n * (n - 1))) * Math.pow(sumsq,2);
- double x4 = -4 * ((double) (n * (n + 1))) * sum * sumCube;
- double x5 = Math.pow(((double) n),2) * ((double) (n+1)) * sumQuad;
-
- return (x1 + x2 + x3 + x4 + x5) /
- ( (double) (n * (n - 1) * (n - 2) * (n - 3)) );
- }
-
- /**
- * Called in "addValue" to insert a new value into the statistic.
- * @param v The value to be added.
- */
- private void insertValue(double v) {
- // The default value of product is NaN, if you
- // try to retrieve the product for a univariate with
- // no values, we return NaN.
- //
- // If this is the first call to insertValue, we want
- // to set product to 1.0, so that our first element
- // is not "cancelled" out by the NaN.
- //
- // For the first value added, the mean is that value,
- // and the variance is zero.
- if( n == 0 ) {
- product = 1.0 ;
- mean = v ;
- pre_variance = 0.0 ;
- variance = 0.0 ;
- }
-
- if( windowSize != Univariate.INFINITE_WINDOW ) {
- if( windowSize == n ) {
- double discarded = doubleArray.addElementRolling( v );
-
- // Remove the influence of the discarded
- sum -= discarded;
- sumsq -= discarded * discarded;
- sumCube -= Math.pow(discarded, 3);
- sumQuad -= Math.pow(discarded, 4);
-
- if(discarded == min) {
- min = doubleArray.getMin();
- } else if(discarded == max){
- max = doubleArray.getMax();
- }
-
- if(product != 0.0){
- // can safely remove discarded value
- product *= v / discarded;
- } else if(discarded == 0.0){
- // need to recompute product
- product = 1.0;
- double[] elements = doubleArray.getElements();
- for( int i = 0; i < elements.length; i++ ) {
- product *= elements[i];
- }
- } // else product = 0 and will still be 0 after discard
-
- } else {
- doubleArray.addElement( v );
- n += 1 ;
- if (v < min) {
- min = v;
- }
- if (v > max) {
- max = v;
- }
- product *= v;
- }
- } else {
- // If the windowSize is infinite please don't take the time to
- // worry about storing any values. We don't need to discard the
- // influence of any single item.
- n += 1 ;
- if (v < min) {
- min = v;
- }
- if (v > max) {
- max = v;
- }
- product *= v;
-
- if ( n > 1 )
- {
- double deviationFromMean = v - mean ;
- double deviationFromMean_overN = deviationFromMean / n ;
- mean += deviationFromMean_overN ;
- pre_variance += (n - 1) * deviationFromMean *
deviationFromMean_overN ;
- variance = pre_variance / (n - 1) ;
- }
- }
-
- sum += v;
- sumsq += v * v;
- sumCube += Math.pow(v,3);
- sumQuad += Math.pow(v,4);
- }
-
- /** Getter for property max.
- * @return Value of property max.
- */
- public double getMax() {
- if (n == 0) {
- return Double.NaN;
- } else {
- return max;
- }
- }
-
- /** Getter for property min.
- * @return Value of property min.
- */
- public double getMin() {
- if (n == 0) {
- return Double.NaN;
- } else {
- return min;
- }
- }
-
- /** Getter for property n.
- * @return Value of property n.
- */
- public int getN() {
- return n;
- }
-
- /** Getter for property sum.
- * @return Value of property sum.
- */
- public double getSum() {
- return sum;
- }
-
- /** Getter for property sumsq.
- * @return Value of property sumsq.
- */
- public double getSumsq() {
- return sumsq;
- }
-
- /** Getter for property sumCube.
- * @return Value of property sumCube.
- */
- public double getSumCube() {
- return sumCube;
- }
-
- /** Getter for property sumQuad.
- * @return Value of property sumQuad.
- */
- public double getSumQuad() {
- return sumQuad;
- }
-
- /**
- * Generates a text report displaying
- * univariate statistics from values that
- * have been added.
- * @return String with line feeds displaying statistics
- */
- public String toString() {
- StringBuffer outBuffer = new StringBuffer();
- outBuffer.append("UnivariateImpl:\n");
- outBuffer.append("n: " + n + "\n");
- outBuffer.append("min: " + min + "\n");
- outBuffer.append("max: " + max + "\n");
- outBuffer.append("mean: " + getMean() + "\n");
- outBuffer.append("std dev: " + getStandardDeviation() + "\n");
- outBuffer.append("skewness: " + getSkewness() + "\n");
- outBuffer.append("kurtosis: " + getKurtosis() + "\n");
- return outBuffer.toString();
- }
-
- /**
- * Resets all sums, product, mean, and variance to 0; resets min and max.
- */
- public void clear() {
- this.sum = this.sumsq = this.sumCube = this.sumQuad = 0.0;
- this.n = 0;
- this.min = Double.MAX_VALUE;
- this.max = Double.MIN_VALUE;
- this.product = Double.NaN;
- this.mean = Double.NaN ;
- this.variance = this.pre_variance = Double.NaN ;
- }
-
- /* (non-Javadoc)
- * @see org.apache.commons.math.Univariate#getWindowSize()
- */
- public int getWindowSize() {
- return windowSize;
- }
-
- /* (non-Javadoc)
- * @see org.apache.commons.math.Univariate#setWindowSize(int)
- */
- public void setWindowSize(int windowSize) {
- String msg = "A fixed window size must be set via the " +
- "UnivariateImpl constructor";
- throw new RuntimeException( msg );
- }
-}
+public class UnivariateImpl
+ extends AbstractStoreUnivariate
+ implements Univariate, Serializable {
+
+ /** hold the window size **/
+ private int windowSize = Univariate.INFINITE_WINDOW;
+
+ /** Just in case the windowSize is not infinite, we need to
+ * keep an array to remember values 0 to N
+ */
+ private DoubleArray doubleArray;
+
+ /** count of values that have been added */
+ private int n = 0;
+
+ /** sum of values that have been added */
+ private double sum = Double.NaN;
+
+ /** sum of the square of each value that has been added */
+ private double sumsq = Double.NaN;
+
+ /** sum of the Cube of each value that has been added */
+ private double sumCube = Double.NaN;
+
+ /** sum of the Quadrate of each value that has been added */
+ private double sumQuad = Double.NaN;
+
+ /** min of values that have been added */
+ private double min = Double.NaN;
+
+ /** max of values that have been added */
+ private double max = Double.NaN;
+
+ /** product of values that have been added */
+ private double product = Double.NaN;
+
+ /** mean of values that have been added */
+ private double mean = Double.NaN;
+
+ /** running ( variance * (n - 1) ) of values that have been added */
+ private double pre_variance = Double.NaN;
+
+ /** variance of values that have been added */
+ private double variance = Double.NaN;
+
+ /** Creates new univariate with an infinite window */
+ public UnivariateImpl() {
+ super();
+ }
+
+ /** Creates a new univariate with a fixed window **/
+ public UnivariateImpl(int window) {
+ super();
+ setWindowSize(window);
+ }
+
+ /** Getter for property n.
+ * @return Value of property n.
+ */
+ public int getN() {
+ return n;
+ }
+
+ /**
+ * Returns the sum of all values contained herein
+ * @see org.apache.commons.math.stat.Univariate#getSum()
+ */
+ public double getSum() {
+ if (windowSize != Univariate.INFINITE_WINDOW) {
+ return super.getSum();
+ }
+
+ return sum;
+ }
+
+ /**
+ * Returns the sun of the squares of all values contained herein
+ * @see org.apache.commons.math.stat.Univariate#getSumsq()
+ */
+ public double getSumsq() {
+ if (windowSize != Univariate.INFINITE_WINDOW) {
+ return super.getSumsq();
+ }
+
+ return sumsq;
+ }
+
+ /**
+ * @see org.apache.commons.math.stat.Univariate#getMean()
+ */
+ public double getMean() {
+ if (windowSize != Univariate.INFINITE_WINDOW) {
+ return super.getMean();
+ }
+
+ return mean;
+ }
+
+ /**
+ * Returns the variance of the values that have been added via West's
+ * algorithm as described by
+ * <a href="http://doi.acm.org/10.1145/359146.359152";>Chan, T. F. and
+ * J. G. Lewis 1979, <i>Communications of the ACM</i>,
+ * vol. 22 no. 9, pp. 526-531.</a>.
+ *
+ * @return The variance of a set of values. Double.NaN is returned for
+ * an empty set of values and 0.0 is returned for a <= 1 value set.
+ */
+ public double getVariance() {
+ if (windowSize != Univariate.INFINITE_WINDOW) {
+ return super.getVariance();
+ }
+
+ return variance;
+ }
+
+ /**
+ * Returns the skewness of the values that have been added as described by
+ * <a href="http://mathworld.wolfram.com/k-Statistic.html";>Equation (6) for
k-Statistics</a>.
+ *
+ * @return The skew of a set of values. Double.NaN is returned for
+ * an empty set of values and 0.0 is returned for a <= 2 value set.
+ */
+ public double getSkewness() {
+ if (windowSize != Univariate.INFINITE_WINDOW) {
+ return super.getSkewness();
+ }
+
+ if (n == 0) {
+ return Double.NaN;
+ }
+
+ if (n <= 2) {
+ /* if n <= 2, skewness to 0.0 */
+ return 0.0;
+ } else {
+ /* else calc the skewness */
+ return (
+ 2 * Math.pow(sum, 3)
+ - 3 * sum * sumsq
+ + ((double) (n * n)) * sumCube)
+ / ((double) (n * (n - 1) * (n - 2)));
+ }
+ }
+
+ /**
+ * Returns the kurtosis of the values that have been added as described by
+ * <a href="http://mathworld.wolfram.com/k-Statistic.html";>Equation (7) for
k-Statistics</a>.
+ *
+ * @return The kurtosis of a set of values. Double.NaN is returned for
+ * an empty set of values and 0.0 is returned for a <= 3 value set.
+ */
+ public double getKurtosis() {
+ if (windowSize != Univariate.INFINITE_WINDOW) {
+ return super.getKurtosis();
+ }
+
+ if (n == 0) {
+ return Double.NaN;
+ }
+
+ if (n <= 3) {
+ /* if n <= 3, kurtosis to 0.0 */
+ return 0.0;
+ } else {
+ /* calc the kurtosis */
+ double x1 = -6 * Math.pow(sum, 4);
+ double x2 = 12 * ((double) n) * Math.pow(sum, 2) * sumsq;
+ double x3 = -3 * ((double) (n * (n - 1))) * Math.pow(sumsq, 2);
+ double x4 = -4 * ((double) (n * (n + 1))) * sum * sumCube;
+ double x5 =
+ Math.pow(((double) n), 2) * ((double) (n + 1)) *
sumQuad;
+
+ return (x1 + x2 + x3 + x4 + x5)
+ / ((double) (n * (n - 1) * (n - 2) * (n - 3)));
+ }
+ }
+
+ /** Getter for property max.
+ * @return Value of property max.
+ */
+ public double getMax() {
+ if (windowSize != Univariate.INFINITE_WINDOW) {
+ return super.getMax();
+ }
+
+ return max;
+ }
+
+ /** Getter for property min.
+ * @return Value of property min.
+ */
+ public double getMin() {
+ if (windowSize != Univariate.INFINITE_WINDOW) {
+ return super.getMin();
+ }
+
+ return min;
+ }
+
+ /**
+ * @see org.apache.commons.math.stat.Univariate#getProduct()
+ */
+ public double getProduct() {
+ if (windowSize != Univariate.INFINITE_WINDOW) {
+ return super.getProduct();
+ }
+
+ return product;
+ }
+
+ /**
+ * @see org.apache.commons.math.stat.Univariate#getGeometricMean()
+ */
+ public double getGeometricMean() {
+
+ if (windowSize != Univariate.INFINITE_WINDOW) {
+ return super.getGeometricMean();
+ }
+
+ if ((product <= 0.0) || (n == 0)) {
+ return Double.NaN;
+ } else {
+ return Math.pow(product, (1.0 / (double) n));
+ }
+ }
+
+ /* (non-Javadoc)
+ * @see org.apache.commons.math.stat.StoreUnivariate#getMode()
+ */
+ public double getMode() {
+ if (windowSize == Univariate.INFINITE_WINDOW) {
+ throw new RuntimeException("Mode is only available if
windowSize is fixed");
+ }
+
+ return super.getMode();
+ }
+
+ /* (non-Javadoc)
+ * @see org.apache.commons.math.stat.StoreUnivariate#getPercentile(double)
+ */
+ public double getPercentile(double p) {
+ if (windowSize == Univariate.INFINITE_WINDOW) {
+ throw new RuntimeException("Percentiles are only available if
windowSize is fixed");
+ }
+
+ return super.getPercentile(p);
+
+ }
+
+ /**
+ * @see org.apache.commons.math.stat.Univariate#addValue(double)
+ */
+ public void addValue(double v) {
+
+ if (windowSize != Univariate.INFINITE_WINDOW) {
+ /* then all getters deligate to AbstractStoreUnivariate
+ * and this clause simply adds/rolls a value in the storage
array
+ */
+ if (windowSize == n) {
+ doubleArray.addElementRolling(v);
+ } else {
+ n++;
+ doubleArray.addElement(v);
+ }
+
+ } else {
+ /* If the windowSize is infinite don't store any values and
there
+ * is no need to discard the influence of any single item.
+ */
+ n++;
+
+ if (n <= 1) {
+ /* if n <= 1, initialize the product, min, max, mean,
variance and pre-variance */
+ product = 1.0;
+ sum = min = max = mean = v;
+ sumsq = Math.pow(v, 2);
+ sumCube = Math.pow(v, 3);
+ sumQuad = Math.pow(v, 4);
+ variance = pre_variance = 0.0;
+ } else {
+ /* otherwise calc these values */
+ product *= v;
+ sum += v;
+ sumsq += Math.pow(v, 2);
+ sumCube += Math.pow(v, 3);
+ sumQuad += Math.pow(v, 4);
+ min = Math.min(min, v);
+ max = Math.max(max, v);
+
+ double deviationFromMean = v - mean;
+ double deviationFromMean_overN = deviationFromMean / n;
+ mean += deviationFromMean_overN;
+ pre_variance += (n - 1)
+ * deviationFromMean
+ * deviationFromMean_overN;
+ variance = pre_variance / (n - 1);
+ }
+ }
+ }
+
+ /**
+ * Generates a text report displaying
+ * univariate statistics from values that
+ * have been added.
+ * @return String with line feeds displaying statistics
+ */
+ public String toString() {
+ StringBuffer outBuffer = new StringBuffer();
+ outBuffer.append("UnivariateImpl:\n");
+ outBuffer.append("n: " + n + "\n");
+ outBuffer.append("min: " + min + "\n");
+ outBuffer.append("max: " + max + "\n");
+ outBuffer.append("mean: " + getMean() + "\n");
+ outBuffer.append("std dev: " + getStandardDeviation() + "\n");
+ outBuffer.append("skewness: " + getSkewness() + "\n");
+ outBuffer.append("kurtosis: " + getKurtosis() + "\n");
+ return outBuffer.toString();
+ }
+
+ /**
+ * Resets all stats to NaN. Reinitializes the Double Array
+ */
+ public void clear() {
+ this.n = 0;
+ this.min = this.max = Double.NaN;
+ this.product = this.mean = Double.NaN;
+ this.variance = this.pre_variance = Double.NaN;
+
+ if (doubleArray != null)
+ doubleArray = new FixedDoubleArray(windowSize);
+ }
+
+ /* (non-Javadoc)
+ * @see org.apache.commons.math.Univariate#getWindowSize()
+ */
+ public int getWindowSize() {
+ return windowSize;
+ }
+
+ /* (non-Javadoc)
+ * @see org.apache.commons.math.Univariate#setWindowSize(int)
+ */
+ public void setWindowSize(int windowSize) {
+ clear();
+ this.windowSize = windowSize;
+ doubleArray = new FixedDoubleArray(windowSize);
+ }
+
+ /* (non-Javadoc)
+ * @see org.apache.commons.math.stat.StoreUnivariate#getValues()
+ */
+ public double[] getValues() {
+ if (windowSize == Univariate.INFINITE_WINDOW) {
+ throw new RuntimeException("Values are only available if
windowSize is fixed");
+ }
+
+ return this.doubleArray.getElements();
+ }
+
+ /* (non-Javadoc)
+ * @see org.apache.commons.math.stat.StoreUnivariate#getElement(int)
+ */
+ public double getElement(int index) {
+ if (windowSize == Univariate.INFINITE_WINDOW) {
+ throw new RuntimeException("Elements are only available if
windowSize is fixed");
+ }
+
+ return this.doubleArray.getElement(index);
+ }
+
+ /* (non-Javadoc)
+ * @see org.apache.commons.math.stat.StoreUnivariate#getSortedValues()
+ */
+ public double[] getSortedValues() {
+ if (windowSize == Univariate.INFINITE_WINDOW) {
+ throw new RuntimeException("SortedValues are only available if
windowSize is fixed");
+ }
+
+ return super.getSortedValues();
+ }
+}
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