Author: billbarker
Date: Mon Dec 14 02:53:40 2009
New Revision: 890159
URL: http://svn.apache.org/viewvc?rev=890159&view=rev
Log:
Add an optimized dotProduct to OpenMapRealVector.
Slightly modified from contribution by Jake Mannix.
JIRA: MATH-317
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java
commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/OpenMapRealVector.java
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java?rev=890159&r1=890158&r2=890159&view=diff
==============================================================================
---
commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java
(original)
+++
commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java
Mon Dec 14 02:53:40 2009
@@ -196,7 +196,7 @@
public double getDistance(RealVector v) throws IllegalArgumentException {
checkVectorDimensions(v);
double d = 0;
- Iterator<Entry> it = sparseIterator();
+ Iterator<Entry> it = iterator();
Entry e;
while (it.hasNext() && (e = it.next()) != null) {
final double diff = e.getValue() - v.getEntry(e.getIndex());
@@ -207,15 +207,7 @@
/** {...@inheritdoc} */
public double getDistance(double[] v) throws IllegalArgumentException {
- checkVectorDimensions(v.length);
- double d = 0;
- Iterator<Entry> it = iterator();
- Entry e;
- while (it.hasNext() && (e = it.next()) != null) {
- final double diff = e.getValue() - v[e.getIndex()];
- d += diff * diff;
- }
- return Math.sqrt(d);
+ return getDistance(new ArrayRealVector(v,false));
}
/** {...@inheritdoc} */
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/OpenMapRealVector.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/OpenMapRealVector.java?rev=890159&r1=890158&r2=890159&view=diff
==============================================================================
---
commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/OpenMapRealVector.java
(original)
+++
commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/OpenMapRealVector.java
Mon Dec 14 02:53:40 2009
@@ -303,6 +303,34 @@
return new OpenMapRealVector(this);
}
+ /**
+ * Optimized method to compute the dot product with an OpenMapRealVector.
+ * Iterates over the smaller of the two.
+ * @param v The vector to compute the dot product with
+ * @return The dot product of <code>this</code> and <code>v</code>
+ * @throws IllegalArgumentException If the dimensions don't match
+ */
+ public double dotProduct(OpenMapRealVector v) throws
IllegalArgumentException {
+ checkVectorDimensions(v.getDimension());
+ boolean thisIsSmaller = entries.size() < v.entries.size();
+ Iterator iter = thisIsSmaller ? entries.iterator() :
v.entries.iterator();
+ OpenIntToDoubleHashMap larger = thisIsSmaller ? v.entries : entries;
+ double d = 0;
+ while(iter.hasNext()) {
+ iter.advance();
+ d += iter.value() * larger.get(iter.key());
+ }
+ return d;
+ }
+
+ /** {...@inheritdoc} */
+ public double dotProduct(RealVector v) throws IllegalArgumentException {
+ if(v instanceof OpenMapRealVector) {
+ return dotProduct((OpenMapRealVector)v);
+ } else {
+ return super.dotProduct(v);
+ }
+ }
/** {...@inheritdoc} */
public OpenMapRealVector ebeDivide(RealVector v) throws
IllegalArgumentException {
