i am solving over-determined system but when i run my code its give me result inner dimension mismatch how to solve it
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l=0:28
N=28
for k=1:7
k1=k+(n*7);
k2=k+(n*7);
M=[1 1 ; e^(j*2*3.14)*(k1-1)*(l/N) e^(j*2*3.14)*(k2-1)*(l/N) ;e^(j*2*3.14)*(k1-1)*(l/N) e^(j*2*3.14)*(k2-1)*(l/N)];
end
2 commentaires
Ced
le 26 Mar 2016
Modifié(e) : Ced
le 27 Mar 2016
You are aware that matlab includes constants such as e and pi?
First row of M: 2 elements
Second row of M: 29 elements (from l)
--> PROBLEM!
EDIT After reading Walter's comment, I realized my answer was not clear. As he correctly points out, you need to use exp(1) to compute e^1. I just meant that you don't have to plug in the "e" number manually.
Walter Roberson
le 27 Mar 2016
MATLAB does not have a constant for e: you would code exp(1) to get e.
Réponse acceptée
Jason Nicholson
le 27 Mar 2016
Modifié(e) : Jason Nicholson
le 27 Mar 2016
Your code is a bit cryptic because it is clear you don't know the right MATLAB syntax. So the way I will try to help is guess at what you were trying to do and rewrite your code.
l=(0:28)'; % size is now 29 x 1
N=28;
for k=1:7
k1=k+(N*7);
k2=k+(N*7);
M=[1, 1 ;
exp(1j*2*pi)*(k1-1)*(l/N), exp(1j*2*pi)*(k2-1)*(l/N) ;
exp(1j*2*pi)*(k1-1)*(l/N), exp(1j*2*pi)*(k2-1)*(l/N)];
end
Note that the code above still doesn't make sense for an over-determined system of equations. Therefore, I am going to speak about over-determined linear algebraic equations systems as follows.
Given: You have the over determined system A*x = b where A is an m x n matrix and m > n. You want to minimize the norm(Ax - b) in the least squares sense (i.e. best coefficient vector x). To do this in MATLAB, use the following:
x = A\b
When A is rectangular rather than square, MATLAB computes the least squares solution.
If this helped you, please mark my answer as the accepted answer. Otherwise, post some more information so that we can try to better answer your question.
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