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Bug about saving a variable

Asked by Isaac on 19 Dec 2011

Hello everybody,

i am experiencing a very strange bug in saving a variable.

Supposing variable name is "xxxxx"

if i execute the instruction

save filetarget xxxxx (which should save the xxxxx variable in the filetarget.mat file)

and then i execute

load filetarget

i receive the following error message: Error using ==>load Unable to read MAT-file C:\....filetarget.mat File may be corrupt

but if i create a variable with a shorter name, that is

x=xxxxx

and then i execute save filetarget x and then load filetarget

everything works...

what can it be??

Thanks in advice!!!!

2 Comments

Daniel on 19 Dec 2011

It works fine on my system. Are your variables really only 5 characters long?

Walter Roberson on 19 Dec 2011

Could you show us the actual variable name you are having problems with?

Which MATLAB version are you using, and which MS Windows version?

Isaac

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3 Answers

Answer by Naz on 19 Dec 2011
x=2;
yourfile='name.mat'; %saves in the current directory  
save yourfile x
load yourfile

Strange... I don't get an error when using variable xxxxx. Maybe matlab has an issue with the path where you want to save it? Try saving it in the current directory first.

Try using this set:

save(yourfile, 'xxxxx');
new=load(yourfile);

where the 'new' variable will be a struct containing your variable xxxxx. To access it, you need this reference:

newVarible=new.xxxxx;

4 Comments

Walter Roberson on 19 Dec 2011

What? No, that would save to yourfile.mat not to name.mat !
save(yourfile, 'x') would be the code.

Naz on 19 Dec 2011

In the code above, the variable 'x' is in the file 'name'.

Walter Roberson on 19 Dec 2011

I'm pretty sure that is not true, Naz.

save yourfile x

is taking advantage of command / function duality such as is described briefly by Steve at http://www.mathworks.com/matlabcentral/newsreader/view_thread/51623

save yourfile x

would be treated as

save('yourfile','x')

which would save to the file named yourfile.mat

If you examine the save() documentation at http://www.mathworks.com/help/techdoc/ref/save.html you will see that in each case where command/function duality is used, the filename given is treated literally rather than being evaluated. For example "save test.mat" does not attempt to extract the field named "mat" from the structure variable "test" and use the value of the field as the file name.

Naz
Answer by Jose Jeremias Caballero on 19 Dec 2011

Hello.

    >> xxxxxxx=rand(3);
    >> save filetarget xxxxxxx
    >> clear all
    >> whos
    >> load filetarget
    >> whos
      Name         Size            Bytes  Class     Attributes
      xxxxxxx      3x3                72  double              
    >> display(xxxxxxx)
    xxxxxxx =
        0.4898    0.7094    0.6797
        0.4456    0.7547    0.6551
        0.6463    0.2760    0.1626

0 Comments

Jose Jeremias Caballero
Answer by Isaac on 20 Dec 2011

I explained myself in a wrong way. The problem is not "usual": saving and loaind usually works well with me, whatever is the name and its length of the variable.

The problem is about one specific variabile... which i dunno why if i save it and then load it .... it tells me that error message "Error using ==>load Unable to read MAT-file C:\....filetarget.mat File may be corrupt" but, more surprisingly, if i save it with another name... it works!!!!

that is:

variable "var1"

save filetarget var1 load filetarget ERROR

BUT:

var2=var1 save filetaget var2 load filetarget

Everything works....

WHYYY :D

6 Comments

Isaac on 20 Dec 2011

the name is "rendimentoSTOXX600"

but i think it should be something else than name... because the same problems is given by another variable which is calculated from "rendimentoSTOXX600"

Jan Simon on 20 Dec 2011

Please post running code and format it as explained in the "Markup help"link on this page.

Jan Simon on 20 Dec 2011

Are you sure, that this is not working:
var1 = rand(10);
save filetarget var1
Data = load('filetarget.mat');

Isaac

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