Estimating polyval in a for loop

Hello,

I have a data of x and Y values which I call Yobserved and Xobserved which follow a simple linear equation model: y = ax + b. I am trying to estimate calculated values of Y which I call Ycalc from already obtained values of a and b.

a and b values are the intercepts and slopes of these straight lines. In length they are 11. so I have a 2 by 11 matrix with 1st column b and 2nd column, a. Now for each pair of a and b value and the observed Y values. I am trying to estimate the predicted Y values of using polyval.

PROBLEM: Calculated Y values from polyval can be of ANY LENGTH for each pair of a and b. I am doing this in a for loop and only the first value of Y gets returned which is not supposed to be the case.

Y value is meant to vary in length since the data that produced a and b were selected according to a criteria. That means Y could be e.g 200X1, or 505X1, etc. Y is a single vector of variable length not a matrix. I just need all these vectors in one matrix.

I cannot predetermine the length of Y unless it has been calculated by polyval making preallocation a little challenging.

Now my question is : how do i return the output of "polyval" i.e Y in the loop since the size of Y changes inside the loop.

I know this is a problem of variable size vectors but not sure how to go about it. Any suggestions would really be of help. Thanks

Here's my code.

MC = [1:0.1:2.0]'; % 

n = length(MC);

for i = 1:length(MC);

      ss = find(ML>=MC(i));

      Msel = ML(ss); % selected data range for which to calculate a and b values

      % calculate b value, avalue and uncertainty in b
      [bvalue(i),stdv(i),aval(i)] = bmaxLE(ML,MC(i)); % function to calculate a and b values

      hh = [-1*bvalue(i),aval(i)]% put a and b in a matrix

      Y = 10.^(polyval(hh,[1,3.2]));% calculate the predicted Y values for each set of a and b
      C1{i} = Y;% put each vector of Y in a cell
  end

Answer 1

[Walter Roberson]

After the loop,

Y = vertcat(C1{:});

If I scan your code correctly, this should result in a something-by-2 matrix. If you want a single row vector instead, switch to horzcat()