means of multiple vectors from different matrices

Hello I am trying to create a mean vector from multiple vectors (n=21) in 20 different matrices. Haven't used Matlab in a while so would greatly appreciate some help.Thanks!

Answer 1

[Matt Fig]

You will need to explain better what you want to do. Give a small example, say 3 matrices, and show what you want to get at the end.

Your example kinda clarifies, but not enough. How is the data stored? Is each chemical a row or column? Say columns.

Say Na is stored in the first column of all matrices and you want the mean:

A = magic(3); % Day 1
B = hankel(1:3); % Day 2
C = toeplitz(1:3); % Day 3
mn = sum([A(:,1);B(:,1);C(:,1)] )/9;

Now depending on how the matrices are stored and named, there could be a better way. For example, using the above matrices:

save matrices A B C
X = load('matrices')
Bigmat = cell2mat(struct2cell(X));
mean(Bigmat) % Column means.

[Nancy]

thanks Matt...here is an example....I have time series (a matrix) of several measurements (say a matrix with chemical concentration of sodium, aluminum and chloride) from day 1, day 2 and day 3. I want to get the mean time series of one chemical element (say sodium) by averaging the time series from the three different days. Does that example help?

[Nancy]

thanks Matt--very helpful--much appreciated!