C++插值内插和外推实现
时间: 2023-07-11 10:46:52 浏览: 52
C++中可以使用多种方法进行插值内插和外推,以下是其中几种方法的实现:
1. 线性插值:
```c++
double linear_interpolation(double x0, double y0, double x1, double y1, double x) {
return y0 + (y1 - y0) * (x - x0) / (x1 - x0);
}
```
2. 拉格朗日插值:
```c++
double lagrange_interpolation(double x, double* x_arr, double* y_arr, int n) {
double result = 0.0;
for (int i = 0; i < n; i++) {
double product = y_arr[i];
for (int j = 0; j < n; j++) {
if (i != j) {
product *= (x - x_arr[j]) / (x_arr[i] - x_arr[j]);
}
}
result += product;
}
return result;
}
```
3. 牛顿插值:
```c++
double newton_interpolation(double x, double* x_arr, double* y_arr, int n) {
double result = y_arr[0];
double* divided_diff = new double[n];
for (int i = 0; i < n; i++) {
divided_diff[i] = y_arr[i];
}
for (int i = 1; i < n; i++) {
for (int j = n - 1; j >= i; j--) {
divided_diff[j] = (divided_diff[j] - divided_diff[j - 1]) / (x_arr[j] - x_arr[j - i]);
}
double product = 1.0;
for (int j = 0; j < i; j++) {
product *= (x - x_arr[j]);
}
result += divided_diff[i] * product;
}
delete[] divided_diff;
return result;
}
```
以上三种方法都可以用于插值内插和外推,只需要根据实际情况选择对应的参数即可。