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MATH-990 

Reduced amount of copying.
Moved consistency checks out of the double loop.


git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1489871 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Gilles Sadowski 2013-06-05 13:48:26 +00:00
parent d8aca35b7a
commit b23c8567c3
1 changed files with 50 additions and 40 deletions
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90
src/main/java/org/apache/commons/math3/util/MathArrays.java
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@ -675,59 +675,69 @@ public class MathArrays {
public static void sortInPlace(double[] x, public static void sortInPlace(double[] x,
final OrderDirection dir, final OrderDirection dir,
double[] ... yList) double[] ... yList)
throws NullArgumentException, DimensionMismatchException { throws NullArgumentException,
DimensionMismatchException {
final int yListLen = yList.length;
final int len = x.length;
// Consistency checks.
if (x == null) { if (x == null) {
throw new NullArgumentException(); throw new NullArgumentException();
} }
for (int j = 0; j < yListLen; j++) {
final int len = x.length; final double[] y = yList[j];
final List<Pair<Double, double[]>> list if (y == null) {
= new ArrayList<Pair<Double, double[]>>(len); throw new NullArgumentException();
}
final int yListLen = yList.length; if (y.length != len) {
for (int i = 0; i < len; i++) { throw new DimensionMismatchException(y.length, len);
final double[] yValues = new double[yListLen];
for (int j = 0; j < yListLen; j++) {
double[] y = yList[j];
if (y == null) {
throw new NullArgumentException();
}
if (y.length != len) {
throw new DimensionMismatchException(y.length, len);
}
yValues[j] = y[i];
} }
list.add(new Pair<Double, double[]>(x[i], yValues));
} }
final Comparator<Pair<Double, double[]>> comp // Associate each abscissa "x[i]" with its index "i".
= new Comparator<Pair<Double, double[]>>() { final List<Pair<Double, Integer>> list
public int compare(Pair<Double, double[]> o1, = new ArrayList<Pair<Double, Integer>>(len);
Pair<Double, double[]> o2) { for (int i = 0; i < len; i++) {
int val; list.add(new Pair<Double, Integer>(x[i], i));
switch (dir) { }
case INCREASING:
val = o1.getKey().compareTo(o2.getKey()); // Create comparators for increasing and decreasing orders.
break; final Comparator<Pair<Double, Integer>> comp
case DECREASING: = dir == MathArrays.OrderDirection.INCREASING ?
val = o2.getKey().compareTo(o1.getKey()); new Comparator<Pair<Double, Integer>>() {
break; public int compare(Pair<Double, Integer> o1,
default: Pair<Double, Integer> o2) {
// Should never happen. return o1.getKey().compareTo(o2.getKey());
throw new MathInternalError(); }
} } : new Comparator<Pair<Double,Integer>>() {
return val; public int compare(Pair<Double, Integer> o1,
Pair<Double, Integer> o2) {
return o2.getKey().compareTo(o1.getKey());
} }
}; };
// Sort.
Collections.sort(list, comp); Collections.sort(list, comp);
// Modify the original array so that its elements are in
// the prescribed order.
// Retrieve indices of original locations.
final int[] indices = new int[len];
for (int i = 0; i < len; i++) { for (int i = 0; i < len; i++) {
final Pair<Double, double[]> e = list.get(i); final Pair<Double, Integer> e = list.get(i);
x[i] = e.getKey(); x[i] = e.getKey();
final double[] yValues = e.getValue(); indices[i] = e.getValue();
for (int j = 0; j < yListLen; j++) { }
yList[j][i] = yValues[j];
// In each of the associated arrays, move the
// elements to their new location.
for (int j = 0; j < yListLen; j++) {
// Input array will be modified in place.
final double[] yInPlace = yList[j];
final double[] yOrig = yInPlace.clone();
for (int i = 0; i < len; i++) {
yInPlace[i] = yOrig[indices[i]];
} }
} }
} }