/**
* Creates a copy of a given {@code DoubleVector} with the same type as the original.
*
* @param source The {@code Vector} to copy.
* @return A copy of {@code source} with the same type.
*/
public static DoubleVector copyOf(DoubleVector source) {
if (source == null) return null;
DoubleVector result = null;
if (source instanceof SparseDoubleVector) {
result = new CompactSparseVector(source.length());
copyFromSparseVector(result, source);
} else if (source instanceof DenseVector || source instanceof ScaledDoubleVector) {
result = new DenseVector(source.length());
for (int i = 0; i < source.length(); ++i) result.set(i, source.get(i));
} else if (source instanceof AmortizedSparseVector) {
result = new AmortizedSparseVector(source.length());
copyFromSparseVector(result, source);
} else if (source instanceof DoubleVectorView) {
DoubleVectorView view = (DoubleVectorView) source;
return copyOf(view.getOriginalVector());
} else {
// Create a copy of the given class using reflection. This code
// assumes that the given implemenation of Vector has a constructor
// which accepts another Vector.
try {
Class<? extends DoubleVector> sourceClazz = source.getClass();
Constructor<? extends DoubleVector> constructor =
sourceClazz.getConstructor(DoubleVector.class);
result = (DoubleVector) constructor.newInstance(source);
} catch (Exception e) {
throw new Error(e);
}
}
return result;
}
/**
* Returns {@code true} if the two vectors are equal to one another. Two {@code Vector} insances
* are considered equal if they contain the same number of elements and all corresponding pairs of
* {@code double} values are equal.
*/
public static boolean equals(DoubleVector v1, DoubleVector v2) {
if (v1.length() == v2.length()) {
int length = v1.length();
for (int i = 0; i < length; ++i) {
if (v1.get(i) != v2.get(i)) return false;
}
return true;
}
return false;
}
@Test
public void invokeMethod() throws ScriptException, NoSuchMethodException {
Object obj = engine.eval("list(execute=sqrt)");
DoubleVector result = (DoubleVector) invocableEngine.invokeMethod(obj, "execute", 16);
assertThat(result.length(), equalTo(1));
assertThat(result.get(0), equalTo(4d));
}
@Test
public void invokeFunction() throws ScriptException, NoSuchMethodException {
engine.eval("f <- function(x) sqrt(x)");
DoubleVector result = (DoubleVector) invocableEngine.invokeFunction("f", 4);
assertThat(result.length(), equalTo(1));
assertThat(result.get(0), equalTo(2d));
}