使用Circshift的Matlab /八度音阶进行数组操作

Question

I'm trying to produce an output that will take the last value of an array, and start the next array with the next lowest value found in that array. If there is no next lowest value I would like it to just end the loop See example of the answer I'm trying to get below.

9.0000   11.0000    5.0000    7.0000    3.0000    7.0100
7.0000    3.0000    7.0100    9.0000   11.0000    5.0000
3.0000    7.0100    9.0000   11.0000    5.0000    7.0000

The code I'm using below only gets the first two rows correct and does something strange at the end any ideas how to fix this.

Code:

clc
a=[9,11,5,7,3,7.01];
[a_sorted, a_idx] = sort(a, 2); %sorts array along with getting index values of numbers
a_sorted=a_sorted'; % sort into col
a_idx=a_idx'; % sort into col
a_val_idx=[a_sorted a_idx]; % combine array

loop_amount=length(find(a<a(end))) %how many values are less than the last value, loop this many times

for yy=1:loop_amount

    a_val=find(a_val_idx(:,1)<a(end)); %find idx of next lowest value from end 
    nxt_low_idx_val=a_val_idx(a_val(end),2) %get idx of the next lowest value from end

    b=circshift(a,[0 (length(a)-nxt_low_idx_val+1)])

    a=b;

end

The results I get are

loop_amount =  3
a =
    9.0000   11.0000    5.0000    7.0000    3.0000    7.0100

nxt_low_idx_val =  4
a =
    7.0000    3.0000    7.0100    9.0000   11.0000    5.0000

nxt_low_idx_val =  5
a =
   11.0000    5.0000    7.0000    3.0000    7.0100    9.0000

nxt_low_idx_val =  6

As you can see the last row should read

nxt_low_idx_val =  2

3.0000    7.0100    9.0000   11.0000    5.0000    7.0000

Any ideas how to fix this?

Thanks

Answer 1

Too lazy to look at your code. How about this?

a = [9,11,5,7,3,7.01];
disp(' ')
disp(a) % display original value
len = length(a);

loop_count = sum(a<a(end)); % as per your code
for count = 1:loop_count
  b = a(1:end-1); % copy of a, will be overwritten
  b(b>a(end)) = NaN; % these values do not count
  if(all(isnan(b)))
    break % exit if there are no lower values
  end
  [aux ind] = max(b); % max of the remaing values
  perm = mod(ind+(0:len-1),len); % cyclic shift
  perm(perm==0) = len; % correct zero to len
  a = a(perm); % do the shift
  disp(a) % display new value
end

Answer 2

I Just needed to move some things under the for loop

clc
a=[9,11,5,7,3,7.01];


loop_amount=length(find(a<a(end))) %how many values are less than the last value, loop this many times

for yy=1:loop_amount
    [a_sorted, a_idx] = sort(a, 2); %sorts array along with getting index values of numbers
    a_sorted=a_sorted'; % sort into col
    a_idx=a_idx'; % sort into col
    a_val_idx=[a_sorted a_idx]; % combine array
    a_val=find(a_val_idx(:,1)<a(end)); %find idx of next lowest value from end 
    nxt_low_idx_val=a_val_idx(a_val(end),2) %get idx of the next lowest value from end

    b=circshift(a,[0 (length(a)-nxt_low_idx_val+1)])

    a=b;

end