/**
* Optimized method to compute the outer product.
*
* @param v The vector to comput the outer product on
* @return The outer product of <code>this</code> and <code>v</code>
* @throws IllegalArgumentException If the dimensions don't match
*/
public OpenMapRealMatrix outerproduct(OpenMapRealVector v) throws IllegalArgumentException {
checkVectorDimensions(v.getDimension());
OpenMapRealMatrix res = new OpenMapRealMatrix(virtualSize, virtualSize);
Iterator iter = entries.iterator();
while (iter.hasNext()) {
iter.advance();
Iterator iter2 = v.getEntries().iterator();
while (iter2.hasNext()) {
iter2.advance();
res.setEntry(iter.key(), iter2.key(), iter.value() * iter2.value());
}
}
return res;
}
/**
* Optimized method to add two OpenMapRealVectors.
*
* @param v Vector to add with
* @return The sum of <code>this</code> with <code>v</code>
* @throws IllegalArgumentException If the dimensions don't match
*/
public OpenMapRealVector add(OpenMapRealVector v) throws IllegalArgumentException {
checkVectorDimensions(v.getDimension());
OpenMapRealVector res = (OpenMapRealVector) copy();
Iterator iter = v.getEntries().iterator();
while (iter.hasNext()) {
iter.advance();
int key = iter.key();
if (entries.containsKey(key)) {
res.setEntry(key, entries.get(key) + iter.value());
} else {
res.setEntry(key, iter.value());
}
}
return res;
}
/**
* Distance between two vectors.
*
* <p>This method computes the distance consistent with L<sub>1</sub> norm, i.e. the sum of the
* absolute values of elements differences.
*
* @param v vector to which distance is requested
* @return distance between two vectors.
*/
public double getL1Distance(OpenMapRealVector v) {
double max = 0;
Iterator iter = entries.iterator();
while (iter.hasNext()) {
iter.advance();
double delta = Math.abs(iter.value() - v.getEntry(iter.key()));
max += delta;
}
iter = v.getEntries().iterator();
while (iter.hasNext()) {
iter.advance();
int key = iter.key();
if (!entries.containsKey(key)) {
double delta = Math.abs(iter.value());
max += Math.abs(delta);
}
}
return max;
}
/**
* Optimized method to compute distance.
*
* @param v The vector to compute distance to
* @return The distance from <code>this</code> and <code>v</code>
* @throws IllegalArgumentException If the dimensions don't match
*/
public double getDistance(OpenMapRealVector v) throws IllegalArgumentException {
Iterator iter = entries.iterator();
double res = 0;
while (iter.hasNext()) {
iter.advance();
int key = iter.key();
double delta;
delta = iter.value() - v.getEntry(key);
res += delta * delta;
}
iter = v.getEntries().iterator();
while (iter.hasNext()) {
iter.advance();
int key = iter.key();
if (!entries.containsKey(key)) {
final double value = iter.value();
res += value * value;
}
}
return Math.sqrt(res);
}
/**
* Implementation Note: This performs an exact comparison, and as a result it is possible for
* {@code a.subtract(b}} to be the zero vector, while {@code a.equals(b) == false}. {@inheritDoc}
*/
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (!(obj instanceof OpenMapRealVector)) {
return false;
}
OpenMapRealVector other = (OpenMapRealVector) obj;
if (virtualSize != other.virtualSize) {
return false;
}
if (Double.doubleToLongBits(epsilon) != Double.doubleToLongBits(other.epsilon)) {
return false;
}
Iterator iter = entries.iterator();
while (iter.hasNext()) {
iter.advance();
double test = other.getEntry(iter.key());
if (Double.doubleToLongBits(test) != Double.doubleToLongBits(iter.value())) {
return false;
}
}
iter = other.getEntries().iterator();
while (iter.hasNext()) {
iter.advance();
double test = iter.value();
if (Double.doubleToLongBits(test) != Double.doubleToLongBits(getEntry(iter.key()))) {
return false;
}
}
return true;
}
/**
* Copy constructor.
*
* @param v The instance to copy from
*/
public OpenMapRealVector(OpenMapRealVector v) {
virtualSize = v.getDimension();
entries = new OpenIntToDoubleHashMap(v.getEntries());
epsilon = v.getEpsilon();
}