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Index problem help?

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JL555 2015-9-22

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编辑： JL555 2015-9-23

采纳的回答： Guillaume

在 MATLAB Online 中打开

for i=1:n
for j=1:n
Pl=P(i)*B(i)(j)*P(j);

seems like i'm getting error with writing B(i)(j)...How will i code it in another way?

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Guillaume 2015-9-22

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编辑：Guillaume 2015-9-22

在 MATLAB Online 中打开

Possibly, you meant to write

Pl(i,j) = P(i)*B(i,j)*P(j)

Or possibly, you meant something else entirely. It's impossible to tell with so little information.

In any case, you should go through the Getting Started tutorial.

Most likely also, the loops are not needed and it can all be done with matrix operations.

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编辑：JL555 2015-9-22

在 MATLAB Online 中打开

   if pmin<Pi;
      pmin=Pi;

pmin is a 1x6 matrix and Pi is 6x1 matrix...why am i still getting inner dimension must agree with <

Walter Roberson 2015-9-22

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You vectorized your code and you did not show us the new code. We can't tell you what needs to be fixed.

JL555 2015-9-22

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在 MATLAB Online 中打开

Pi=x(1:m,1:n1);
for i=1:n
    for j=1:n
        if pmin<Pi;
            pmin=Pi;
        else if Pi<pmax;
                Pi=pmax;
                C=Pi(i)*B(i,j)*Pi(j);
                C1=B0(i)*Pi(i);
                Pl=C+C1+Boo;
                Pi=Pd+Pl;
              end
          end
      end
  end

Walter Roberson 2015-9-22

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在 MATLAB Online 中打开

That code will not generate the error message you indicate.

Why did you not follow the conversation in http://www.mathworks.com/matlabcentral/answers/241944-using-summation-and-modulus

Note that you are doing a test of one vector compared to another. You would get a matrix dimensions must agree error there but not an inner dimensions must agree error.

If you were to switch so the two vectors are the same orientation then you face the problem that the test

if A < B

means the same as

if all(A < B)

and is only true if the comparison holds for every item in the vector.

JL555 2015-9-22

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Actually the link to that answer is not valid anymore something terribly wrong with that program and i have a new one.And yes i'm getting a matrix dimension must agree ...so it is not possible to use the 'lt' to generate a matrix of 1x6 or should i compare with only one elemnt of that matrix?

Walter Roberson 2015-9-22

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在 MATLAB Online 中打开

if pmin(:) < Pi(:)

Walter Roberson 2015-9-22

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It is obvious to me from the code that you should be rewriting using matrix algebra. But every time I fix your code for you, you change it completely and look like you have not understood anything I wrote. You also do not answer questions about what size of output you are expecting from each step. It leaves me reluctant to assist.

JL555 2015-9-22

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编辑：Walter Roberson 2015-9-22

在 MATLAB Online 中打开

function [Ft Pi Pl]=FPAeld(x)
global objfun data pmin pmax Pd B B0 Boo
n=length(data(:,1));
[m n1]=size(x);
Pi=x(1:m,1:n1);
for i=1:n
    for j=1:n
        if data(1,4)<Pi;
            data(1,4)=Pi;
        else if Pi<data(1,5);
                Pi=data(1,5);
                C=Pi(i)*B(i,j)*Pi(j);
                C1=B0(i)*Pi(i);
                Pl=C+C1+Boo;
                Pi=Pd+Pl;
              end
          end
      end
  end
  a=data(:,1);
  b=data(:,2);
  c=data(:,3);
  e=data(:,6);
  f=data(:,7);
  for i=1:n,
      Pi=[Pi Pi(i)];
      Ft=a(i)+b(i)*Pi(i)+c(i)*Pi(i).^2+abs(e(i)*sin(f(i)*(pmin-Pi(i))));
  end

ok here the new code .....i'm feeding 'x' from an algorithm..its a 6x1 matrix. What i need in the end is Pi value which will have 6 values and i'll feed that value to the Ft formula in the end

Walter Roberson 2015-9-22

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Pi is a vector but if the if comparing it to data(1,4) holds then you assign data(1,4) to replace ALL of the vector.

JL555 2015-9-22

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ok last question...'x' out there like i said is a 6x1 matrix..in the 5th line my Pi should be a 6x1 matrix too right? but i'm getting a single value ..why?

Walter Roberson 2015-9-22

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Why not just assign

Pi = x;

Since you use all of x?

JL555 2015-9-22

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Yes all of x...But i did this instead Pi=[m n1]; still i,m getting one value..

JL555 2015-9-22

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Oh and one thing ,i have the pseudo code of an algorithm ...any tutorials of how i can write that pseudo code into a matlab program..

Walter Roberson 2015-9-22

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在 MATLAB Online 中打开

I explained several days ago why

Pi=[Pi Pi(i)];

is going to just end up copying the same element over and over again. You are ignoring everything I write about why your program is not working.

JL555 2015-9-22

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ok sorry dude i've been working with this program for one month now i managed to eliminate all the errors but everything is wrong with the programming...anyway are u familiar with economic load dispatch??