Polyfit will not work on my computer.

The code is correct and I copied and pasted it into my friends matlabs and it works fine. I keep getting the following error code on mine whenever I try it. I got polyfit to work with just single numbers but whenever I plug in variables that are representing matrices, it will not work.

[KSSV]

It should work actually....can you tell what does which polyfit show up?

[Rob Giagnorio]

I'm sorry, I'm not the best at matlab, what do you mean by which polyfit?

[KSSV]

type which polyfit in your work space.....and tell us the result...IN my PC it shows up:

C:\Program Files\MATLAB\R2017a\toolbox\matlab\polyfun\polyfit.m

[Rob Giagnorio]

C:\Program Files\MATLAB\R2017a\toolbox\matlab\polyfun\polyfit.m

That is what I got from that

[KSSV]

You got a tool box...so it should work....

[Rob Giagnorio]

Yeah, I have no idea what is happening. I've tried multiple different codes, deleting and retyping, just about everything. My professor said no one else has had that problem and he has no clue what is going on.

[Walter Roberson]

Which check

which -all max

I suspect you might have your own max.m interfering in the computation.

[Rob Giagnorio]

which -all max
built-in (C:\Program Files\MATLAB\R2017a\toolbox\matlab\datafun\max)
C:\Program Files\MATLAB\R2017a\toolbox\matlab\datatypes\@categorical\max.m  % categorical method
C:\Program Files\MATLAB\R2017a\toolbox\matlab\timefun\@duration\max.m       % duration method
C:\Program Files\MATLAB\R2017a\toolbox\matlab\timefun\@datetime\max.m       % datetime method
C:\Program Files\MATLAB\R2017a\toolbox\matlab\bigdata\@tall\max.m           % tall method
C:\Program Files\MATLAB\R2017a\toolbox\matlab\timeseries\@timeseries\max.m  % timeseries method

this is what i got there

[Walter Roberson]

That does look okay.

At the command line, command

dbstop if error

and run the program. When it stops with the error about index exceeded, please show

n
size(m)
m(n)
size(Y)

Also please show the output for

which sort

[Rob Giagnorio]

which sort built-in (C:\Program Files\MATLAB\R2017a\toolbox\matlab\datafun\@double\sort) % double method

[Rob Giagnorio]

[Walter Roberson]

Ummm... when it stops in the debugger could you show

which size
size(A)
A

Answer 1

[Jan]

The problem occurs in normest1. The failing line looks unsual for Matlab code:

est = full(temp(n)); v = zeros(n,1); v(m(n)) = 1; w = Y(:,m(n));

Matlab's JIT acceleration cannot work properly, if you write multiple commands in one line. So is this really written by MathWorks?

When n=2 and m is a scalar, the code must fail. Step through the code of normest1 to find the meaning of these variables.

[Rob Giagnorio]

Sorry, how do I go about stepping through the code?

[Walter Roberson]

dbstop in normest1

Run the code. It will stop at the first executable line of normest1. You can then examine variables and

dbstep

to execute a line at a time.

[Rob Giagnorio]

[Walter Roberson]

It is not normest1 that you should execute after the "dbstop": you should invoke polyfit like before. When it stops in normest1 then you can look at the inputs and dbstep through the lines.

[Rob Giagnorio]