Numerical derivative of points

Dear All: I have the y and x values and I want to get the dy/dx for each point without losing any point.What is the best way of function with a high precision to be used to find the dy/dx? Please help me with this issue. Thanks. With my best regards, Mohammed

Answer 1

[Star Strider]

I would use the gradient (link) function. The output is the same size as the imput.

[KHAN]

Thank you very much for your answer.

[KHAN]

Dear Star Strider: I have checked the gradient function. It is assumed that the spacing between points in each direction is assumed to be 1. In my case, the spacing between points in each direction is not the same. Could explain more on this problem? Thanks. Mohammed

[John D'Errico]

Did you look at the other arguments to gradient? If not, why not? That is, if you have a difference that is not 1, you can still solve the problem using gradient.

[Star Strider]

The function assumes the same spacing for the points, although it does not have to be 1. You can set it with the ‘h’ variable. One way to get ‘dy/dx’ using the function is:

h = some_value;
dydx = gradient(y, h) ./ gradient(x, h);

Experiment to get the result you want.

[KHAN]

Thank you Star Strider.

[Star Strider]

As always, my pleasure.