Make a for loop for the following code

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susman
susman 2021-2-16
评论： susman 2021-2-22
I am estimating the probabilities over time.
for example, my data matrix is 6 by 5 (where 6 is the number of simulations and 5 is the number of time periods).
data = [2, 2 , 1, 1, 1, 1; 2, 2 , 1, 1, 1, 2; 2, 2 , 1, 2, 1, 2; 2, 2 , 1, 2, 1, 2; 2, 3 , 2, 2, 1, 2]
States = unique([data(:,1); data(:,2)]) % Find the unique rows of A based on the data in the first two columns.
[TFinitial, fromstateAge27] = ismember(sequence(:,3), States) % logical arrays
[TF25, tostateAge27] = ismember(sequence(:,4), States) % logical array
went_from_to_countAge27 = accumarray( [fromstateAge27(:), tostateAge27(:)], 1, []) % frequency of transitions from one state to another
went_from_to_probAge27 = went_from_to_countAge27 ./ sum(went_from_to_countAge27) % probability of transition from one state to another
Now I want to make a for loop that runs the above code for each column of matrix "data".
For the above code (column 1 to 2), my output is "went_from_to_probAge27 "
for column 2 to 3, my output will be "went_from_to_probAge28"
from column 3 to 4, my output will be "went_from_to_probAge29" and so on.
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susman
susman 2021-2-16
As I am developing a discrete time markov chain, in which transition probabilities are changiny every period. So I found it as the easiest way to to have seperate variable for each transition matrix for period t. Is there any better way of doing it?
Rik
Rik 2021-2-16
Yes, by using the method Jan shows below. That way you can still use indexing to access the data, instead of having to generate the variable name every time you want use the variable.

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Jan
Jan 2021-2-16
Naming a variable "went_from_to_probAge27" hides important information in the name. There this information can be accessed by really awkward methods only. See TUTORIAL: why and how to avoid EVAL
Use arrays instead. Because here you need 27 as data, a struct array would be efficient:
Data(1).Age = 27;
[TFinitial, Data(1).fromstate] = ismember(sequence(:,3), States);
[TF25, Data(1).tostate] = ismember(sequence(:,4), States)
...
Does this help to solve your problem?
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susman
susman 2021-2-22
yes, but only the last command gives an error. This one
went_from_to_countAge(k) = ...
it is because, the output matrix "went_from_to_countAge(k)" is changing its size for each k. and the code ends up with error.
I have also posted the question in a new link as:
Using accumarry and changing size of output - MATLAB Answers - MATLAB Central (mathworks.com)
any suggestion?

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