我正在尝试使用 SplineInterpolator 和 PolynomialSplineFunction将数据集加倍。我认为我已经走得很远了(我可能错过了一些异常处理):
SplineInterpolator splineInterp;
public double[] doubledArray(double[] y){
double[] yy = new double[y.length*2];
// make a double version of y w/ -1 for "null" values
for(int i = 0; i < yy.length; i++){
if(i%2 == 0)
yy[i] = y[i];
else if(i == yy.length-1)
yy[i] = yy[0];
else
yy[i] = -1;
}
// make a corresponding x array to satisfy SplineInterpolator.interpolate
double[] x = new double[y.length];
for(int i = 0; i < x.length; i++)
x[i] = i;
splineInterp = new SplineInterpolator();
PolynomialSplineFunction polySplineF = splineInterp.interpolate(x, y);
for(int i = 0; i < yy.length; i++){
if(yy[i] == -1){
yy[i] = polySplineF.value(i);
// breaks down halfway through polySplineF.value expects and array of y.length
}
}
return yy;
}
但是上面的代码最迟会在最后一个 for 循环中崩溃。那么,我的第一部分或多或少是正确的吗?有了多项式样条函数后,如何使用它来创建更大的数据集?
最佳答案
如果有人在家里跟随,这是我为此想出的实现:
private double[] multiplyArray(double[] y){
// An array 2 or 4 or N times bigger than the original:
double[] yy = new double[y.length*arrayMultiplier];
// An array representing the indices of the original:
double[] x = new double[y.length];
for(int i = 0; i < x.length; i++)
x[i] = i;
// Get and instance of SplineInterpolator:
SplineInterpolator splineInterp = new SplineInterpolator();
// Use that instance's interpolate() function to a PolynomialSplineFunction
// fitting your data, points y at indices x.
PolynomialSplineFunction polySplineF = splineInterp.interpolate(x, y);
// Use the PolynomialSplineFunction to fill in your larger array by supplying
// index values divided by the arrayMultiplier
for(int i = 0; i < yy.length; i++){
yy[i] = polySplineF.value((double)(i/arrayMultiplier));
}
return yy;
}
如果有人需要的话,我还想出了如何进行可能更有用的填空用法。
关于Java:使用多项式样条函数 (Apache) 将数据集加倍,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/13497136/