# Derivative of unequally spaced data points without decreasing the length of a vector?

조회 수: 35(최근 30일)
friet 2018년 2월 5일
답변: Walter Roberson 2018년 2월 5일
Hello Matlab,
I have data ponts that are not equally spaced
x=[0.097
0.477
0.934
4.835
15.590
46.645
69.371
100.709
165.249
277.846
382.978
1000.64
1519.83
1991.60
2544.96
3023.40
3589.94
4159.93
4473.43
5186.36
6316.71
7134.15
9125.71
10571.90
12565.82
14916.64
16859.92
];
y=[20.96
21.33
20.77
20.96
21.14
21.33
20.24
19.71
17.90
15.98
14.51
10.05
8.37
7.40
6.49
6.05
5.54
5.17
4.82
4.57
4.26
3.87
3.52
3.25
3.08
2.80
2.61
];
dydx = diff(y(:))./diff(x(:))
z= y.*dydx;
First is dydx the right way to differentiate the data points? Second dydx will give me will give me one element shorter than y and have trouble calculating z. What is the best way to calculate z without shortening. I'm currently using shorten the y axis:
z= y(2:end).*dydx;
However, I dont like shorting my y axis.
Any help is appreciated. Thanks GH

댓글을 달려면 로그인하십시오.

### 답변(1개)

Walter Roberson 2018년 2월 5일

댓글을 달려면 로그인하십시오.

### 범주

Find more on Image Arithmetic in Help Center and File Exchange

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by