How to fix broken function code?

Hey! Here is my function and I am trying to estimate the values of b_1 and b_0, but when I am running my code, I get following messages:

"Error using/

Matrix dimensions must agree."

"Error in function sovittaja (line 5):

s_2 = sum((x.*y)/(delta_y.^2));"

"Error in (line 16):

sovittaja(f,v,delta_v).

Here is my function code called "sovittaja":

function [b, bci] = sovittaja(x,y,delta_y)

%%Helper variables:

s_1 = sum(1./(delta_y.^2));

s_2 = sum((x.*y)/(delta_y.^2));

s_3 = sum(x./(delta_y.^2));

s_4 = sum(y./(delta_y.^2));

s_5 = sum(x.^2/(delta_y.^2));

%%Defining D:

D = (s_1*s_5)-(s_3)^2;

%%Analyyttiset lausekkeet:

b_1 = (1/D)*((s_1)*(s_2)-(s_3)*(s_4));

b_0 = (1/D)*((s_5)*(s_4)-(s_3)*(s_2));

%%Margin of errors:

delta_b_1 = sqrt((1/D)*(s_1));

delta_b_0 = sqrt((1/D)*(s_5));

%%Indexs of matrix bci :

bci_11 = b_0 - delta_b_0;

bci_12 = b_1 - delta_b_1;

bci_21 = b_0 + delta_b_0;

bci_22 = b_1 + delta_b_1;

%% Return values:

b = [b_0, b_1];

bci = [bci_11,bci_12;bci_21,bci_22];

And here is what I want to do with the function "sovittaja":

clear all

close all

% Measurement:

i=[1,2,3,4,5]';

% Frequency:

x=[519,549,688,740,821]';

% Voltage:

y=[1.0,1.2,1.9,2.4,2.3]';

% Margin of Error:

delta_y=[0.15,0.40,0.20,0.30,0.10];

sovittaja(x,y,delta_y)

What should I do to make the code work? And how could I plot these?

Thank you for the help!

Answer 1

[Stephen23]

Use array division here:

s_2 = sum((x.*y)./(delta_y.^2));
%               ^^

and here:

s_5 = sum(x.^2./(delta_y.^2));
%             ^^

and possibly in some other locations: check all division and power operations!

Learn the difference:

https://www.mathworks.com/help/matlab/matlab_prog/array-vs-matrix-operations.html

As a rule of thumb: if you are not doing linear algebra then use array operations.

[Jenni]

Great thank you, the code is working now!