I have an error using walsh. It says

t1=-1;
t2=3;
N=2048;
t0 = (t2-t1)/N;
t = t1:t0:t2-t0;
xt = t.^3-4*t.^2+t+6;
n=4; 
H=walsh(n,N);  %%THERE IN AN ERROR. Error using  ()  Too many input                                   arguments. Expected 0 (in addition to System object), got 2.
K=t0*diag(H*H')
C=t0*H*xt'./K
xxt=C'*H;
ee=1/(t2-t1)*t0*sum((xt-xxt).^2);
ee=1/(t2-t1)*(t0*sum(xt.^2)-K'*C.^2);
close all; hold all;
plot(t,xt);
plot(t,xxt,'Color','red');
xlabel('t sek');ylabel('x(t)');

Answer 1

[Walter Roberson]

walsh() is not the name of any Mathworks supplied function.

walsh() is the name of one File Exchange contribution, https://www.mathworks.com/matlabcentral/fileexchange/50202-walsh-n but that function expects only a single parameter.

My guess is that you did, https://www.mathworks.com/help/comm/ref/comm.walshcode-system-object.html

walsh = comm.WalshCode();

If so, then the resulting object is invoked as a function using

H = walsh();

with no parameters. You might previously have done,

walsh.Length = N;
walsh.Index = n;

[Teo Humar]

Well my collegue ran the exact same code and it worked for him.

I don't see any sintax mistake. What does Expected 0 (in addition to System object), got 2. mean?

[Torsten]

It means that no input arguments to "walsh" are expected, but that you supplied two (namely n and N) instead.

[Walter Roberson]

Well my collegue ran the exact same code and it worked for him.

That suggests that your colleague has a walsh.m that you do not have.

What shows up for

which -all walsh

on your system, and on your colleague's system?

[Teo Humar]

Its only a variable for me

[Walter Roberson]

And how is that variable created?

[Image Analyst]

@Teo Humar, wow -- it's really hard to get information from you so we can help you. And I'm not sure why. Did you overlook Walter's request:

What shows up for

which -all walsh

on your system, and on your colleague's system?

otherwise, why didn't you answer it? And please answer his last question about how you created the "walsh" variable. Help us to help you.

Answer 2

[Image Analyst]

I recreated your problem:

>> walsh

Execution of script walsh as a function is not supported:

C:\Users\Mark\Documents\MATLAB\work\Tests\walsh.m

Error in walsh (line 8)

H=walsh(n,N); %%THERE IN AN ERROR. Error using () Too many input arguments. Expected 0 (in addition to System object), got 2.

^^^^^^^^^^

The problem is that you named your script walsh.m. Give your m-file some different name, like testwalsh.m or something.

[Walter Roberson]

S = [
    "t1=-1;"
"t2=3;"
"N=2048;"
"t0 = (t2-t1)/N;"
"t = t1:t0:t2-t0;"
"xt = t.^3-4*t.^2+t+6;"
"n=4;"
"H=walsh(n,N);"];
writelines(S, 'walsh.m');

walsh

Execution of script walsh as a function is not supported:
/users/mss.system.xh7fl/walsh.m

Error in walsh (line 8)
H=walsh(n,N);

That does not say anything about "Too many input arguments. Expected 0 (in addition to System object), got 2.". In order to get that message, walsh() needs to be a system object.

[Image Analyst]

You're right - I was seeing the comment instead of an actual system error. I was confused because it was also in red.