implementing FOR LOOP for beginning and end

Question

gabriele fadanelli 2020-3-27

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https://ww2.mathworks.cn/matlabcentral/answers/513394-implementing-for-loop-for-beginning-and-end

回答： Abhisek Pradhan 2020-4-2

Hi everybody. I want to implement this code in which I would love to avoid for loop, but most of all I wish I could avoid putting out of the cycle the first and last values of the matrix rows.

freq=2;  %just a frequency or a time
t_buckets=[1 5 8 90];  %vector of times upon which I am constructing my "buckets"
t=(1/freq:1/freq:t_buckets(end)); %building a time vector spaced with the frequency up to the last period in t_buckets
w_buck=zeros(length(t_buckets),length(t)); %initialize the matrix for my result, which are, as tu say, increasing vectors from zero up to a value of time then decreasing going to zero up to the next point in t_buckets
w_buck(1,1:freq*t_buckets(1))=1;  %need to put this part out of the for loop
w_buck(1,freq*t_buckets(1)+1:freq*t_buckets(1+1))=(t(freq*t_buckets(1)+1:freq*t_buckets(2))-t_buckets(2))/(t_buckets(1)-t_buckets(2));  
for i=2:length(t_buckets)-1    %recursive formula to get every row with necessary "bucket" values for times
w_buck(i,freq*t_buckets(i-1):freq*t_buckets(i)-1)=(t(freq*t_buckets(i-1):freq*t_buckets(i)-1)-t_buckets(i-1))/(t_buckets(i)-t_buckets(i-1));
w_buck(i,freq*t_buckets(i))=1;
w_buck(i,freq*t_buckets(i)+1:freq*t_buckets(i+1))=(t(freq*t_buckets(i)+1:freq*t_buckets(i+1))-t_buckets(i+1))/(t_buckets(i)-t_buckets(i+1));  
end
%need to put last part out of the for loop otherwiae it doesn t work
w_buck(length(t_buckets),freq*t_buckets(end-1):freq*t_buckets(end)-1)=(t(freq*t_buckets(end-1):freq*t_buckets(end)-1)-t_buckets(end-1))/(t_buckets(end)-t_buckets(end-1));
w_buck(length(t_buckets),freq*t_buckets(length(t_buckets)))=1;