Undefined operator '*' for input arguments of type 'matlab.gr​aphics.pri​mitive.Lin​e'.

Hello, I am working on Python scripting to make changes over the proposed DoE in Matlab in order to make changes in the model and obtain the results.

When I am passing commands to make changes in the cell structure, I get the error mentioned above. I have tried looking further but I think it has to do with some mathematical oepration on a graphical database which aren't comptabile to work together. But I can't find any other way to make changes in the diemension of my cell.

The problem is when I am trying to define the printf statement whererin I want to write the new data to my text file(pyhton model database script) and then change my mdoel in the abaqus (in background).

Any help is much appreciated. I have described the exact lcoation of error in the text below:::

Problem is mainly in this section and line highlighted in the text below towards the end where I am assigning the value " 0.5 * b(1) "

replaceLine=144;
    fid=fopen('BASE_MODEL_MDB.py','r+');
    for k=1:(replaceLine-1)
        fgetl(fid);
    end
    fseek(fid,0,'cof');
    fprintf(fid,' ''Model-1'', RectangularProfile(a=1.0, b=%5.4f, name=''Profile-2''), ', 0.5*b(1));  %HERE
    fclose(fid);

[Walter Roberson]

You do not show us how you created b, but we can predict that at some point earlier you had a statement similar to

b = plot(something);

I suspect that b might be a collection of lines, not just a single line. If you need to, you can extract information from the lines, but at the moment it is not obvious what information you might want to extract. Speculating wildly,

bx = b(1).XData;
by = b(1).YData;
ratio = (max(by) - min(by) / (max(bx) - min(bx));
fprintf(fid,' ''Model-1'', RectangularProfile(a=1.0, b=%5.4f, name=''Profile-2''), ', 0.5*ratio);

[Nicholas Ayres]

Could you please clarify what the variable

b

is. Maybe insert the code where it is defined into your question (and respond to me saying you have done so, so that I get the notification).

If I am not mistaken, it appears that b is taken from a graphics handle and you are just incorrectly indexing it to find the data point you are requiring.

Knowing what b is would help me more directly answer your question.

:)

[anant mehrotra]

Thank you for your prompt response.

'b' is the section dimension defined in Abaqus. I have modeled using rectangular section and I had to define a and b for the section width and length. Now I am trying to change that. In python script at line I have mentioned, there is this profile dimensions a and b and I want r edit b :)

b is 50x1 and contains value ranging from 0.0015-0.007 [m].

Answer 1

[anant mehrotra]

Nicholas Ayres sure I can help you with that. I am going to attach two files which will help you in understanding what b is. The problem is, earlier I wasn't using variable b and I was simply calling it cell_section and assigning values to it as per my DoE (generateDoE.m). And I was using the same in "printf" statement to modify my model in ABAQUS. Everytime I would run the main code, it gave me an error that cell_section is not defined or unknown variabel/function.

So what I did next is to call the variables I am changing with the same name the ABAQUS uses, maybe that could bring this error of graphical and assigning this mathematical value. But anyway, I am attaching the matlab code here.

"python_assembly.m" is called inside "Main.m" which is called inside "DoE.m".

I hope this helps and thank you for your prompt response.

[Walter Roberson]

Your current code that you posted has

    fprintf(fid,' 4.90673637390137), value=%5.4f',0.5*line(1)); %MIGHT HAVE TO CHANGE THIS FULLY

It is risky to name a variable line because line() is the name of the line drawing function that underlays plotting.

In theory line is a parameter to your function,

    function [length] = python_assembly(b,line,run)

Unfortunately you did not happen to include Main.m

global b line run

Global variables typically lead to mistakes. Much much more often than they solve problems.

http://matlab.wikia.com/wiki/FAQ#How_can_I_share_data_between_callback_functions_in_my_GUI.28s.29.3F

[anant mehrotra]

Well, thank you so much for picking those silly errors that I have made.

I wasn't using

global b line run

before in my code. Rather, I was simply using

    cell_sect = data(j,2);
    cell_dim = data(j,3);
    run = j;

But in doing so, it gives me an error that cell_sect and cell_dim are unknown or undefined even when I would define

    cell_dim=[];
    cell_sect=[];

outside the loop. So below is how it was done before:

    runs= 50; %no. of runs in the DoE
    data= generateDoE(runs); %to calculate the DoE table
    output=zeros(runs,4); %sets the results table - a 50x4 table
    cell_sect=[];
    cell_dim=[];    
    run=[];
    for j=1:runs
        cell_sect = data(j,2);
        cell_dim= data(j,3);
        run = j;
        Main            %to run the main.m program calling PYHTON script 
        output(j,:) = [run b line E]; %iteration; thickness; dimension; energy absorbed
    end

[anant mehrotra]

Walter Roberson

I would also like to mention that even if I stop using line and even passing it as function parameter which I definitely will, the problem is already there with line 31

fprintf(fid,' ''Model-1'', RectangularProfile(a=1.0, b=%5.4f, name=''Profile-2''), ', 0.5*b(1));

[Walter Roberson]

Unfortunately you did not happen to include Main.m . Or a current copy of your code. It is not useful for us to guess about what your current code might be: we need actual current code to debug.

[anant mehrotra]

I have made only a few changes and here I am sending all the files that my code is made of!

Thanks :)

[anant mehrotra]

Is there any progress on the debug, it's been over two weeks and I have been waiting to get some help from the learned. I have tried to make some changes though!

[Steven Lord]

Set an error breakpoint. Run your code. When you reach the line where the error gets thrown, look at the class of the variable b. I'm pretty sure it will not be a numeric vector but will be a graphics object created by the plot or line functions.

If that's the case, start searching backwards in your code or use the dbstop function to set a breakpoint to determine exactly where in the code the plot function gets called. As stated in the description of the file input on that documentation page, "If file is not a MATLAB code file (for instance, it is a built-in or MDL-file), then MATLAB issues a warning. MATLAB cannot pause in the file, so it pauses before executing the file."

[anant mehrotra]

Thank you for the suggestion. I think it has to do with my mathematical operation being carried on something which is graphical.

The section profile, since I am using a rectangular section has the dimensions a and b, where b=1.2 mm. Now I wish to change the section width i.e., b. So I am reading the file and using 'fprintf', writing a new value assigning b=%5.4f which is equal to half of t_2(i), i.e. I am using a mathematical operation 0.5*t_2(i)

Secondly, the program is giving error in the very intial stages where I am assigning values t_2 to be used later. But Matlab keeps giving me the following error:

>>> variable t_2 is undefined.