Update of /var/cvs/speeltuin/mihxil/statistics/src/org/mmbase/util/math
In directory james.mmbase.org:/tmp/cvs-serv23551/src/org/mmbase/util/math
Modified Files:
Measurement.java
Log Message:
details
See also:
http://cvs.mmbase.org/viewcvs/speeltuin/mihxil/statistics/src/org/mmbase/util/math
Index: Measurement.java
===================================================================
RCS file:
/var/cvs/speeltuin/mihxil/statistics/src/org/mmbase/util/math/Measurement.java,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -b -r1.2 -r1.3
--- Measurement.java 10 Oct 2008 16:38:21 -0000 1.2
+++ Measurement.java 15 Oct 2008 11:45:51 -0000 1.3
@@ -14,9 +14,12 @@
/**
* Represents a set of measurement values. The value represents the average
value.
+ * [EMAIL PROTECTED] #toString} presnent the current value, but only the
relevant digits. The standard
+ * deviation [EMAIL PROTECTED] #getStandardDeviation} is used to determin what
digits are relevant.
+ *
* @author Michiel Meeuwissen
* @since mm-statistics-1.0
- * @version $Id: Measurement.java,v 1.2 2008/10/10 16:38:21 michiel Exp $
+ * @version $Id: Measurement.java,v 1.3 2008/10/15 11:45:51 michiel Exp $
*/
@@ -36,6 +39,9 @@
this.count = count;
}
+ /**
+ * Enters a new value.
+ */
public Measurement enter(double d) {
sum += d;
squareSum += d * d;
@@ -43,11 +49,11 @@
return this;
}
-
-
/**
- * Assuming that this measurement is is from the same set, add it to the
already existing
- * statistics
+ * Assuming that the measurement <code>m</code> is from the same set, add
it to the already existing
+ * statistics.
+ * See also [EMAIL PROTECTED] #add(Measurement)} which is something
entirely different.
+ * @param d
*/
public Measurement enter(Measurement m) {
sum += m.sum;
@@ -112,16 +118,16 @@
*/
public Measurement add(Measurement m) {
// think about this...
- return new Measurement(m.count * sum + count + m.sum, 0,count *
m.count);
+ return new Measurement(m.count * sum + count + m.sum, /* err */ 0,
count * m.count);
}
private static NumberFormat SCIENTIFIC = new
DecimalFormat("0.###############E0", new DecimalFormatSymbols(Locale.US));
/**
- * Returns 10 to the power i
+ * Returns 10 to the power i, a utility in java.lang.Math for that lacks.
*/
- private static double pow10(int i) {
- double result = 1.0;
+ public static double pow10(int i) {
+ double result = 1;
while (i > 0) {
result *= 10;
i--;
@@ -161,69 +167,103 @@
/**
+ * Split a double up in 2 numbers, a double approximeately 1 (the
'coefficent'), and an integer
+ * indicating the order of magnitude (the 'exponent').
+ *
+ */
+ private static class SplitNumber {
+ public double coefficient;
+ public int exponent;
+ public SplitNumber(double in) {
+ try {
+ String[] sStd = SCIENTIFIC.format(in).split("E");
+ coefficient = Double.valueOf(sStd[0]);
+ exponent = Integer.valueOf(sStd[1]);
+ } catch (Exception e) {
+ coefficient = in;
+ exponent = 0;
+ }
+ }
+ public String toString() {
+ return coefficient + "\u00B710" + superscript(exponent);
+ //return coefficient + "E" + exponent;
+ }
+
+ }
+
+ /**
+ * A crude order of magnitude implemention
+ */
+ private int log10(double d) {
+ int result = 0;
+ while (d > 1) {
+ d /= 10;
+ result++;
+ }
+ while (d < 0.1) {
+ d *= 10;
+ result--;
+ }
+ return result;
+ }
+
+
+ /**
* Represents the mean value in a scientific notation (using unciode
characters).
* The value of the standard deviation is used to determin how many digits
can sensibly be shown.
*/
@Override public String toString() {
- double stdCoefficient;
- int stdExponent;
- {
- double std = getStandardDeviation();
- String[] sStd = SCIENTIFIC.format(std).split("E");
- stdCoefficient = Double.valueOf(sStd[0]);
- stdExponent = Integer.valueOf(sStd[1]);
- }
+ SplitNumber std = new SplitNumber(getStandardDeviation());
+ SplitNumber mean = new SplitNumber(getMean());
+
+ // use difference of order of magnitude of std to determin how mean
digits of the mean are
+ // relevant
+ int magnitudeDifference = mean.exponent - std.exponent;
+ //System.out.println("Md: " + mean + " " + std + magnitudeDifference);
+ int meanDigits = Math.max(0, Math.abs(magnitudeDifference)) + 1;
- int meanExponent;
- float meanCoefficient;
- {
- double mean = getMean();
- String[] sMean = SCIENTIFIC.format(mean).split("E");
- meanCoefficient = Float.valueOf(sMean[0]);
- meanExponent = Integer.valueOf(sMean[1]);
+ // for std starting with '1' we allow an extra digit.
+ if (std.coefficient < 2) {
+ meanDigits++;
}
- // use difference of order of magnitude of std to determin how mean
digits of the mean are
- // relevant
- int magnitudeDifference = meanExponent - stdExponent;
- int meanDigits = Math.max(0, Math.abs(magnitudeDifference));
+ //System.out.println("number of relevant digits " + meanDigits + " ("
+ std + ")");
// The exponent of the mean is leading, so we simply justify the
'coefficient' of std to
// match the exponent of mean.
- stdCoefficient /= pow10(magnitudeDifference);
+ std.coefficient /= pow10(magnitudeDifference);
+
// For numbers close to 1, we don't use scientific notation.
- if (Math.abs(meanExponent) < minimumExponent) {
- double pow = pow10(meanExponent);
- meanExponent = 0;
- meanCoefficient *= pow;
- stdCoefficient *= pow;
+ if (Math.abs(mean.exponent) < minimumExponent) {
+ double pow = pow10(mean.exponent);
+ mean.exponent = 0;
+ mean.coefficient *= pow;
+ std.coefficient *= pow;
}
- System.out.println(meanDigits);
- // for std starting with '1' we allow an extra digit.
- if (stdCoefficient < 2) {
- meanDigits++;
- }
+ //System.out.println("me: " + mean);
+
- System.out.println(meanDigits);
- boolean useE = meanExponent != 0;
+ boolean useE = mean.exponent != 0;
NumberFormat nf = NumberFormat.getInstance(Locale.US);
- nf.setMaximumFractionDigits(meanDigits);
- nf.setMinimumFractionDigits(meanDigits);
+ int fd = meanDigits - log10(mean.coefficient);
+ //System.out.println(meanDigits + " -> " + mean + " -> " + fd);
+ nf.setMaximumFractionDigits(fd);
+ nf.setMinimumFractionDigits(fd);
nf.setGroupingUsed(false);
return
(useE ? "(" : "") +
- nf.format(meanCoefficient) +
+ nf.format(mean.coefficient) +
" \u00B1 " + /* +/- */
- nf.format(stdCoefficient) +
+ nf.format(std.coefficient) +
(useE ?
(")\u00B710" + /* .10 */
- superscript(meanExponent))
+ superscript(mean.exponent))
: "");
}
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