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我有一個數組，它位於for循環內部，它首先被轉換爲一個列表，然後分成兩部分，列表的第一部分存儲在s1列表中，第二部分部分被存儲在W1，這是要直到循環結束，並在方法結束時，我將回到S1和W1是這樣的代碼，我已經這樣做了遠完成遞歸：在java中分割兩部分的列表
public Pair daubTrans(double s[]) throws Exception
{
final int N = s.length;
int n;
//double t1[] = new double[100000];
//List<Double> t1 = new ArrayList<Double>();
// double s1[] = new double[100000];
List<double[]> w1 = new ArrayList<double[]>();
List<double[]> s1 = new ArrayList<double[]>();
List<double[]> lList = new ArrayList<double[]>();
//List<double[]> t1 = new ArrayList<double[]>();
for (n = N; n >= 4; n >>= 1) {
double[] t1= transform(s, n);
int length = t1.length;
// System.out.println(n);
// LinkedList<double> t1 =new LinkedList<double>(Arrays.asList(t1));
/* for(double[] d: t1)
{
t1.add(d);
}*/
lList = Arrays.asList(t1);
length=lList.size();
//System.out.print(lList.size());
// System.arraycopy(src, srcPos, dest, destPos, length)
/* s1= t1.subList(0, 1);
w1= t1.subList(0, 1); */
/* if(n==N)
{
s1= lList.subList(0, length/2-1);
w1= lList.subList(length/2-1, length);
}
else
{
s1=lList.subList((length/2), length);
w1=lList.subList((length/2), length);
} */
// System.arraycopy(t1,0, s1, n==N?0:t1.size()/2-1, t1.size()/2-1);
// System.arraycopy(t1,(length/2), w1, n==N?0:t1.size()/2-1, t1.size()/2-1);
// System.out.println(w1.length);
}
return new Pair(s1, w1);
}
其中pair類定義爲返回2列表，並且transform將返回存儲在t1數組中的double類型的數組。 現在我在將t1數組轉換爲列表類型以及如何將由t1元素形成的列表拆分爲2個部分時遇到問題。用於變換的代碼是 - ：
protected double[] transform(double a[], int n)
{
if (n >= 4) {
int i, j;
int half = n >> 1;
double tmp[] = new double[n];
i = 0;
for (j = 0; j < n-3; j = j + 2) {
tmp[i] = a[j]*h0 + a[j+1]*h1 + a[j+2]*h2 + a[j+3]*h3;
tmp[i+half] = a[j]*g0 + a[j+1]*g1 + a[j+2]*g2 + a[j+3]*g3;
i++;
}
// System.out.println(i);
tmp[i] = a[n-2]*h0 + a[n-1]*h1 + a[0]*h2 + a[1]*h3;
tmp[i+half] = a[n-2]*g0 + a[n-1]*g1 + a[0]*g2 + a[1]*g3;
for (i = 0; i < n; i++) {
a[i] = tmp[i];
}
}
return a;
} // transform
這是整個代碼 - ：
import java.util.Arrays;
import java.util.List;
import java.util.*;
import java.lang.Math.*;
class daub {
protected final double sqrt_3 = Math.sqrt(3);
protected final double denom = 4 * Math.sqrt(2);
//
// forward transform scaling (smoothing) coefficients
//
protected final double h0 = (1 + sqrt_3)/denom;
protected final double h1 = (3 + sqrt_3)/denom;
protected final double h2 = (3 - sqrt_3)/denom;
protected final double h3 = (1 - sqrt_3)/denom;
//
// forward transform wavelet coefficients
//
protected final double g0 = h3;
protected final double g1 = -h2;
protected final double g2 = h1;
protected final double g3 = -h0;
//
// Inverse transform coefficients for smoothed values
//
protected final double Ih0 = h2;
protected final double Ih1 = g2; // h1
protected final double Ih2 = h0;
protected final double Ih3 = g0; // h3
//
// Inverse transform for wavelet values
//
protected final double Ig0 = h3;
protected final double Ig1 = g3; // -h0
protected final double Ig2 = h1;
protected final double Ig3 = g1; // -h2
List<Double> doubleList = new ArrayList<Double>();
/**
<p>
Forward wavelet transform.
protected double[] transform(double a[], int n)
{
if (n >= 4) {
int i, j;
int half = n >> 1;
double tmp[] = new double[n];
i = 0;
for (j = 0; j < n-3; j = j + 2) {
tmp[i] = a[j]*h0 + a[j+1]*h1 + a[j+2]*h2 + a[j+3]*h3;
tmp[i+half] = a[j]*g0 + a[j+1]*g1 + a[j+2]*g2 + a[j+3]*g3;
i++;
}
// System.out.println(i);
tmp[i] = a[n-2]*h0 + a[n-1]*h1 + a[0]*h2 + a[1]*h3;
tmp[i+half] = a[n-2]*g0 + a[n-1]*g1 + a[0]*g2 + a[1]*g3;
for (i = 0; i < n; i++) {
a[i] = tmp[i];
}
}
return a;
} //改變
protected void invTransform(double a[], int n)
{
if (n >= 4) {
int i, j;
int half = n >> 1;
int halfPls1 = half + 1;
double tmp[] = new double[n];
// last smooth val last coef. first smooth first coef
tmp[0] = a[half-1]*Ih0 + a[n-1]*Ih1 + a[0]*Ih2 + a[half]*Ih3;
tmp[1] = a[half-1]*Ig0 + a[n-1]*Ig1 + a[0]*Ig2 + a[half]*Ig3;
j = 2;
for (i = 0; i < half-1; i++) {
// smooth val coef. val smooth val coef. val
tmp[j++] = a[i]*Ih0 + a[i+half]*Ih1 + a[i+1]*Ih2 + a[i+halfPls1]*Ih3;
tmp[j++] = a[i]*Ig0 + a[i+half]*Ig1 + a[i+1]*Ig2 + a[i+halfPls1]*Ig3;
}
for (i = 0; i < n; i++) {
a[i] = tmp[i];
}
}
}
/**
Forward Daubechies D4 transform
*/
public Pair daubTrans(double s[]) throws Exception
{
final int N = s.length;
int n;
//double t1[] = new double[100000];
//List<Double> t1 = new ArrayList<Double>();
// double s1[] = new double[100000];
List<double[]> w1 = new ArrayList<double[]>();
List<double[]> s1 = new ArrayList<double[]>();
List<double[]> lList = new ArrayList<double[]>();
//List<double[]> t1 = new ArrayList<double[]>();
for (n = N; n >= 4; n >>= 1) {
double[] t1= transform(s, n);
int length = t1.length;
// System.out.println(n);
// LinkedList<double> t1 =new LinkedList<double>(Arrays.asList(t1));
/* for(double[] d: t1)
{
t1.add(d);
}*/
lList = Arrays.asList(t1);
length=lList.size();
//System.out.print(lList.size());
// System.arraycopy(src, srcPos, dest, destPos, length)
/* s1= t1.subList(0, 1);
w1= t1.subList(0, 1); */
if(n==N)
{
s1= lList.subList(0, length/2-1);
w1= lList.subList(length/2-1, length);
}
else
{
s1=lList.subList((length/2), length);
w1=lList.subList((length/2), length);
}
// System.arraycopy(t1,0, s1, n==N?0:t1.size()/2-1, t1.size()/2-1);
// System.arraycopy(t1,(length/2), w1, n==N?0:t1.size()/2-1, t1.size()/2-1);
// System.out.println(w1.length);
}
return new Pair(s1, w1);
}
/**
我建議你使用帶* auto-formatting *的IDE。 – Christian
你應該提供更多的細節，「現在我遇到了問題......」 – guest
@客戶我在從數組類型轉換爲列表類型時出錯，我無法將lList拆分成2個部分for循環 – user3262269