error using std (used to work and works on other people's computer)

Hi, I'm trying to applicate BTC coding to a matrix and I get an error using std even though my matrix is composed of doubles

My friend sent me his working program but it does not work on my computer.

PS: I'm pretty sure my program used to work just fine when I first programmed it

function [mo,so,mf,sf,bRecons] = btcBlock(b0rigin)
bRecons = double(b0rigin);
mo = mean(bRecons(:),1);
so = std(bRecons(:),1);
q=0;
for l = 1 : 1 : size(bRecons,1)
    for c = 1 : 1 : size(bRecons,2)
        if bRecons(l,c) < mo 
            bRecons(l,c) = 0;
        else
            bRecons(l,c) = 1;
            q = q + 1;
        end
    end
end
m = size(b0rigin,1) * size(b0rigin,1);
inf = mo - so*sqrt((q)/(m-q));
supp = mo + so*sqrt((m-q)/(q));
inf = floor(inf);
supp = floor(supp);
for l = 1 : 1 : size(bRecons,1)
    for c = 1 : 1 : size(bRecons,2)
        if bRecons(l,c) == 0
            bRecons(l,c) = inf;
        else
            bRecons(l,c) = supp;
        end
    end
end
mf = mean(bRecons(:),1);
sf = std(bRecons(:),1);

end

here is what I type

A =

   [245   239   249   239
   245   245   239   235
   245   245   245   245
   245   235   235   239]
   
btcBlock(A)

Here is what I get

Error using var
Too many input arguments.

Error in std (line 59)
y = sqrt(var(varargin{:}));

Error in btcBlock (line 4)
so = std(bRecons(:),1);

Thank you in advance

[Star Strider]

bastien alves posted as an Answer:

I forgot to put my friend's code, that does the same thing, works on his computer, but not mine

function btcBlock
N = 4;

bOrigin = [245 239 249 239;
           245 245 239 235;
           245 245 245 245;
           245 235 235 239];

bRecons = zeros(4);

m = mean(mean(bOrigin));
s = std(bOrigin(:) ,1);

q = 0;

for i= 1:N
    for j = 1:N
        if (bOrigin(i , j) > m) 
            bRecons(i, j) = 1;
            q = q + 1;
        else
            bRecons(i, j) = 0;
        end
    end
end

a = floor(m - s * sqrt(q / (N^2 - q)));
b = floor(m + s * sqrt((N^2 - q) / q));

for i= 1:N
    for j = 1:N
        if (bRecons(i , j) == 0)
            bRecons(i, j) = a;
        else
            bRecons(i, j) = b;
        end
    end
end

mRecons = mean(mean(bRecons));
sRecons = std(bRecons(:) ,1);

a
b
bRecons

m
s
mRecons
sRecons
end

Answer 1

[Star Strider]

My guess is that you have variables named ‘std’ and ‘var’.

Check that by running these in a script of your Command Window:

which std -all
which var -all

If the first entry in the result is:

std is a variable.

and similarly for ‘var’, you have likely found the problem. The solution is to rename the variables.

[bastien alves]

which std -all
which var -all
D:\matlab\toolbox\matlab\datafun\std.m
D:\matlab\toolbox\matlab\datatypes\duration\@duration\std.m  % duration method
D:\matlab\toolbox\matlab\datatypes\datetime\@datetime\std.m  % datetime method
D:\matlab\toolbox\matlab\bigdata\@tall\std.m                 % tall method
D:\matlab\toolbox\matlab\timeseries\@timeseries\std.m        % timeseries method
C:\Users\basti\Desktop\tp_lab\comm_tbx5.2\var.m
D:\matlab\toolbox\matlab\bigdata\@tall\var.m           % tall method
D:\matlab\toolbox\matlab\timeseries\@timeseries\var.m  % timeseries method
D:\matlab\toolbox\matlab\datafun\var.m                 % Shadowed

not the issue it seems..

[Star Strider]

O.K., that hypothesis is rejected!

My only other suggestion is to run these:

restoredefaultpath 
rehash toolboxcache 

If that also fails, Contact Support and include the URL of this thread in your message so that you do not have to repeat everything, and MathWorks knows what you have already attempted.

[bastien alves]

It still does not work, thank you for your time I will contact the support !

[Star Strider]

My pleasure!

Sorry ...

(I will delete my Answer in a few hours.)

[Walter Roberson]

Look at your output. All of your files are in D:\matlab except for

C:\Users\basti\Desktop\tp_lab\comm_tbx5.2\var.m

So whatever that is, it is interfering with the regular use of var()

You need to either remove that directory for the MATLAB path or else rename that file.

[Star Strider]

Walter —

Thank you! I didn’t notice that.

[bastien alves]

The thing in C is in a library provided by the university for another exercise, even with the path removed it did not change the error message.

[Walter Roberson]

Then try again with the

which var

The error message says the problem is on line 59 of var.m but line 59 of var.m is comments in all reasonably-recent versions.

[bastien alves]

which var
D:\matlab\toolbox\matlab\datafun\var.m

[Walter Roberson]

And is it still telling you

Error using var
Too many input arguments.
Error in std (line 59)
y = sqrt(var(varargin{:}));

??

[bastien alves]

yes

[Star Strider]

bastien alves —

You need to change the name of this ‘var’:

C:\Users\basti\Desktop\tp_lab\comm_tbx5.2\var.m

to something else, and all references to it in the other project code that uses it.

Then, the MATLAB var function should work without problems.

[Image Analyst]

Yes, because that's the first var.m in the list that "which" gave you, that's the one it will use. You'll need to change the name of var.m AND std.m or move them down in the path.

Is that the one you or they WANT/INTEND to use for some reason?

Why did your university give you a folder of utilities that has the same name as built-in functions? The custom std() they gave you expects exactly one input argument, not 2 like you tried to use. So that's why you get the error.

[bastien alves]

okay I did not know that, but I still get the same error after removing the file from the path

[Star Strider]

The file may still be hiding somewhere. The definitive fix is to rename the function itself, and all references to it in the project code you were given.

I echo Image Analyst’s last two-sentence paragraph! Why would your university give you code with a function that overshadows the MATLAB var funciton? You and your fellow students need to bring that up to whomever is responsible for it.