How can I create a loop that iterates thru +/- values of an array to find a solution?
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Nick
el 18 de Abr. de 2017
Comentada: Nick
el 21 de Abr. de 2017
Basically, the code I'm trying to write will take an array of data, sum it, and find the solution. The sum is known before hand, but whether the data values are positive or negative are not. I'm thinking I could do this using some sort of double for loop marking coefficients as either 1 or -1 but I'm stuck. Any advice? (I'll show an example)
clear,clc
summ = 2
data = [8, 12, 2]
%loops
%...
%SOLUTION
ans = [8 -12 6]
>>
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Roger Stafford
el 18 de Abr. de 2017
If ‘data’ is a row vector and ‘summ’ is the desired sum, do this:
n = length(data);
d = dec2bin(0:2^n-1,n)-‘0’;
d = repmat(data,2^n,1).*(2*d-1);
f = find(sum(d,2)==summ);
s = d(f,:);
Each row of s should be a “solution” for you with appropriate sign changes, if any are found. It is assumed here that all elements of ‘data’ are integers - otherwise the exact equality requirement in the ‘find’ operation would be too demanding.
Warning: Beware of data vectors that are too long - they can result in an enormous ‘d’ array.
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