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Widening, added getCounts(), getRequiredScores().

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git-svn-id: svn+ssh://src.earth.threerings.net/vilya/trunk@474 c613c5cb-e716-0410-b11b-feb51c14d237
This commit is contained in:
Michael Bayne
2007-10-30 00:15:53 +00:00
parent adaf80af0a
commit 1bcaff4c59
1 changed files with 49 additions and 44 deletions
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src/java/com/threerings/parlor/rating/util/Percentiler.java
+49 -44
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@@ -31,8 +31,7 @@ import com.samskivert.util.StringUtil;
import com.threerings.parlor.Log; import com.threerings.parlor.Log;
/** /**
* Used to keep track of the percentile distribution of positive values * Used to keep track of the percentile distribution of positive values (generally puzzle scores).
* (generally puzzle scores).
*/ */
public class Percentiler public class Percentiler
{ {
@@ -64,10 +63,9 @@ public class Percentiler
} }
/** /**
* Records a value, updating the histogram but not the percentiles (a * Records a value, updating the histogram but not the percentiles (a call to {@link
* call to {@link #recomputePercentiles} is required for that and is * #recomputePercentiles} is required for that and is sufficiently expensive that it shouldn't
* sufficiently expensive that it shouldn't be done every time a value * be done every time a value is added).
* is added).
*/ */
public void recordValue (float value) public void recordValue (float value)
{ {
@@ -79,21 +77,17 @@ public class Percentiler
*/ */
public void recordValue (float value, boolean logNewMax) public void recordValue (float value, boolean logNewMax)
{ {
// if this value is larger than our maximum value, we need to // if this value is larger than our maximum value, we need to redistribute our buckets
// redistribute our buckets
if (value > _max) { if (value > _max) {
// determine what our new maximum should be: twenty percent // determine what our new maximum should be: twenty percent again larger than this
// again larger than this newly seen maximum and rounded to an // newly seen maximum and rounded to an integer value
// integer value
int newmax = (int)Math.ceil(value*1.2); int newmax = (int)Math.ceil(value*1.2);
float newdelta = (float)newmax / BUCKET_COUNT; float newdelta = (float)newmax / BUCKET_COUNT;
if (logNewMax) { if (logNewMax) {
Log.info("Resizing [newmax=" + newmax + Log.info("Resizing [newmax=" + newmax + ", oldmax=" + _max + "].");
", oldmax=" + _max + "].");
if (newmax > 2 * _max) { if (newmax > 2 * _max) {
Log.info("Holy christ! Big newmax [value=" + value + Log.info("Holy christ! Big newmax [value=" + value + ", oldmax=" + _max + "].");
", oldmax=" + _max + "].");
} }
} }
@@ -102,15 +96,14 @@ public class Percentiler
int[] counts = new int[BUCKET_COUNT]; int[] counts = new int[BUCKET_COUNT];
float oval = delta, nval = newdelta; float oval = delta, nval = newdelta;
for (int ii = 0, ni = 0; ii < BUCKET_COUNT; ii++, oval += delta) { for (int ii = 0, ni = 0; ii < BUCKET_COUNT; ii++, oval += delta) {
// if this old bucket is entirely contained within a new // if this old bucket is entirely contained within a new bucket, add all of its
// bucket, add all of its counts to the new bucket // counts to the new bucket
if (oval <= nval) { if (oval <= nval) {
counts[ni] += _counts[ii]; counts[ni] += _counts[ii];
} else { } else {
// otherwise, we need to add the appropriate fraction // otherwise, we need to add the appropriate fraction of this bucket's counts
// of this bucket's counts to the two new buckets into // to the two new buckets into which it falls
// which it falls
float fraction = (nval - (oval - delta)) / delta; float fraction = (nval - (oval - delta)) / delta;
int lesser = Math.round(_counts[ii] * fraction); int lesser = Math.round(_counts[ii] * fraction);
counts[ni] += lesser; counts[ni] += lesser;
@@ -167,11 +160,10 @@ public class Percentiler
} }
/** /**
* Returns the percent of all numbers seen that are lower than the * Returns the percent of all numbers seen that are lower than the specified value. This value
* specified value. This value can range from zero to 100 (100 in the * can range from zero to 100 (100 in the case where this is the highest value ever seen by
* case where this is the highest value ever seen by this * this percentiler). This value reflects the percentiles computed as of the most recent call
* percentiler). This value reflects the percentiles computed as of * to {@link #recomputePercentiles}.
* the most recent call to {@link #recomputePercentiles}.
*/ */
public int getPercentile (float value) public int getPercentile (float value)
{ {
@@ -179,9 +171,8 @@ public class Percentiler
} }
/** /**
* Returns the score necessary to attain the specified percentile. * Returns the score necessary to attain the specified percentile. This value reflects the
* This value reflects the percentiles computed as of the most recent * percentiles computed as of the most recent call to {@link #recomputePercentiles}.
* call to {@link #recomputePercentiles}.
* *
* @param percentile the desired percentile (from 0 to 99 inclusive). * @param percentile the desired percentile (from 0 to 99 inclusive).
*/ */
@@ -200,8 +191,28 @@ public class Percentiler
} }
/** /**
* Recomputes the percentile cutoffs based on the values recorded * Returns the scores required to obtain a percentile rating from 0 to 100.
* since the last percentile computation. */
public float[] getRequiredScores ()
{
float[] scores = new float[101];
for (int ii = 0; ii <= 100; ii++) {
scores[ii] = getRequiredScore(ii);
}
return scores;
}
/**
* Returns the counts for each bucket.
*/
public int[] getCounts ()
{
return _counts.clone();
}
/**
* Recomputes the percentile cutoffs based on the values recorded since the last percentile
* computation.
*/ */
public void recomputePercentiles () public void recomputePercentiles ()
{ {
@@ -214,8 +225,7 @@ public class Percentiler
// compute the reverse mapping (percentile to minimum score) // compute the reverse mapping (percentile to minimum score)
for (int ii = 0, pp = 0; ii < BUCKET_COUNT; ii++) { for (int ii = 0, pp = 0; ii < BUCKET_COUNT; ii++) {
// scan forward to the percentile bucket that maps to this // scan forward to the percentile bucket that maps to this percentile
// percentile
while (_percentile[pp] < ii && pp < (BUCKET_COUNT-1)) { while (_percentile[pp] < ii && pp < (BUCKET_COUNT-1)) {
pp++; pp++;
} }
@@ -224,8 +234,7 @@ public class Percentiler
} }
/** /**
* Converts this percentiler to a byte array so that it may be stored * Converts this percentiler to a byte array so that it may be stored into a database.
* into a database.
*/ */
public byte[] toBytes () public byte[] toBytes ()
{ {
@@ -259,8 +268,7 @@ public class Percentiler
} }
/** /**
* Dumps out our data in a format that can be used to generate a * Dumps out our data in a format that can be used to generate a gnuplot.
* gnuplot.
*/ */
public void dumpGnuPlot (PrintStream out) public void dumpGnuPlot (PrintStream out)
{ {
@@ -271,8 +279,7 @@ public class Percentiler
} }
/** /**
* Dumps a text representation of this percentiler to the supplied * Dumps a text representation of this percentiler to the supplied print stream.
* print stream.
*/ */
public void dump (PrintStream out) public void dump (PrintStream out)
{ {
@@ -284,8 +291,7 @@ public class Percentiler
} }
} }
// figure out how many digits are needed to display the biggest // figure out how many digits are needed to display the biggest bucket's size
// bucket's size
int digits = (int)Math.ceil(Math.log(max) / Math.log(10)); int digits = (int)Math.ceil(Math.log(max) / Math.log(10));
digits = Math.max(digits, 1); digits = Math.max(digits, 1);
@@ -339,8 +345,7 @@ public class Percentiler
{ {
int idx = Math.min(Math.round(value * BUCKET_COUNT / _max), 99); int idx = Math.min(Math.round(value * BUCKET_COUNT / _max), 99);
if (idx < 0 || idx >= BUCKET_COUNT) { if (idx < 0 || idx >= BUCKET_COUNT) {
Log.warning("'" + value + "' caused bogus bucket index (" + Log.warning("'" + value + "' caused bogus bucket index (" + idx + ") to be computed.");
idx + ") to be computed.");
Thread.dumpStack(); Thread.dumpStack();
return 0; return 0;
} }
@@ -368,8 +373,8 @@ public class Percentiler
/** The bucket associated with each percentile. */ /** The bucket associated with each percentile. */
protected byte[] _reverse = new byte[BUCKET_COUNT]; protected byte[] _reverse = new byte[BUCKET_COUNT];
/** The number of divisions between zero and our maximum value, which /** The number of divisions between zero and our maximum value, which defines the granularity
* defines the granularity of our histogram. */ * of our histogram. */
protected static final int BUCKET_COUNT = 100; protected static final int BUCKET_COUNT = 100;
/** Number of bytes in an int; makes code clearer. */ /** Number of bytes in an int; makes code clearer. */