Fitting data for each row of a matrix

10 次查看（过去 30 天）
Nikolas Spiliopoulos
编辑： Daniela Conforti 2019-1-16
Hi there,
I have a matrix 8760x8 and I would like to fit the data of each row (8 values) with a vector like this: [1 2 3 4 5 6 7 8]
Is it possible to do it ?
thanks
  1 个评论
Stephen23
Stephen23 2017-6-27
@Nikolas Spiliopoulos: and what is the expected output of this "fitting"?

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

dpb
dpb 2017-6-27
编辑：dpb 2017-6-27
Guessing the intent Stephen has asked for,
x=1:8; % the independent variable vector
nrow=size(data,1); % rows in data array (8760 but don't use "magic numbers)"
coeff=zeros(nrow,2); % preallocate for the coefficient array
for ix=1:nrow
coeff(ix,:)=polyfit(x,data(ix,:),1); % coefficients of linear fit on each row
end
See
doc polyfit
doc polyval
for details on them. Could also use fit if have Curve Fitting TB and return a fit object containing the coefficients and other info as alternative. If do go this route will have to pass x,row vector as columns.
None of the fitting tools are fully vectorized to do the fit on an array of columns so do need to iterate over the array.
  3 个评论
显示 1更早的评论
dpb
dpb 2017-6-27
Typo --
coeff(ix,:)=polyfit(x,annual_temperature_data(ix,:),1);
i is the Matlab builtin sqrt(-1).
Daniela Conforti
Daniela Conforti 2019-1-16
编辑：Daniela Conforti 2019-1-16
Hi, you know how can I use "polyfit" whitout using a for-loop?
I have the same problem described in this question but I'm using a matrix with millions of rows, therefore it requires a lot of time.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Descriptive Statistics 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by