How to do a double fourier transform or double summation equation in Matlab?

4 次查看（过去 30 天）

Tyann Hardyn 2022-5-30

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1730025-how-to-do-a-double-fourier-transform-or-double-summation-equation-in-matlab

编辑： Tyann Hardyn 2022-5-31

Hi Community,

Iam very confused to this equation, because it should be written in a double fourier transform which re very difficult for me.... SO here is the equation i should solve in my Thesis :

T is hour of the years (it can be replaced with a datenum, right?) and M is month number. I just want to know how this difficult equation should be written as a code in Matlab... Im very confused.... I think it would be written in a combination of symsum, syms, and etc, but i still doubt how to write it correctly in Matlab.... WOuld anyone lend me a hand for this equation, please... Thank you so much, everyone... /.\ /.\ /.\

2 个评论
显示无隐藏无

Hiro Yoshino 2022-5-30

This is not a Fourier transform but a Fourier series expansion.

Although I am unfamiliar with this type, all you need is determine A_n^m term upto 6. You may want to make a reference to this for example. Find orthogonal functions and multiply them to the given equatio and you can obtain A_n^m terms.

Tyann Hardyn 2022-5-31

@Hiro Im sorry, Sir. But the m actually not an exponent number just like An^m... In other ways, the equation is like this :

Iam just wonder, Is the equation use for loop or not, Sir? Thank you very much

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Walter Roberson 2022-5-30

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1730025-how-to-do-a-double-fourier-transform-or-double-summation-equation-in-matlab#answer_974340

T cannot be replaced by a datetime. datetime objects cannot be multiplied by anything.

At one level, T could potentially be replaced by a duration() object, as durations can be multiplied... but you cannot take cos() of a duration.

syms T M

syms A [6 6]

syms alpha [1 6]

syms beta [1 6]

n = (1:6).';

m = 1:6;

Sq_est = sum(sum(A .* cos(m .* T + alpha) .* cos(n .* M + beta)))

Sq_est =

8 个评论
显示 6更早的评论隐藏 6更早的评论

Tyann Hardyn 2022-5-31

编辑：Tyann Hardyn 2022-5-31

Alright, Sir.. So the input of T variable is hour of the year, sir? and the M is month number (ex. January = 1, February = 2, etc), and the A is the data in T and M?

Tyann Hardyn 2022-5-31