Least squares matrix?

%Constants NumRocks=[1608 1277 1025 851 726 438 102 53 9 5 1]; %Number of rockfalls vector Vol=[0.01 0.02 0.03 0.04 0.05 0.1 0.5 1 5 10 100]; %Volume in meters cubed

%Least Squares Method A=[NumRocks',ones(11,1)]; y=Vol'; b=[inv(A.*A').*A'.*y]

Getting error: Matrix dimensions must agree.

Answer 1

[Star Strider]

Use the mldivide,\ (link) operator instead:

b = A\y;

b =
   -19.1869e-003
    21.2449e+000

[Michelle Babak]

Thank you! Is it possible to use the least-squares formula though?

[Star Strider]

My pleasure!

The mldivide function solves the equation in the least-squares sense.

You have the correct idea, however the derivation requires matrix operations, not element-wise operations. (You also have the order of the matrix and its transpose reversed.)

This works:

b = (A'*A)\A'*y

giving the same result as posted earlier.

It is more efficient and accurate to use this version than to use:

b = inv(A'*A)*A'*y

that again gives the same result.