(MATLAB beginner) How can I solve this error: In an assignment A(:) = B, the number of elements in A and B must be the same.

I'm trying to use MATLAB for my SWMM project in calibrating certain parameters. Shown below was the part of the program:

runvol_mea=[2.071
        ];

RunVol_mea=runvol_mea(1,:);

peakf=[0.122
    ];

PeakF_mea=peakf(1,:);

% Upper and Lower boundaries of parameters

lb = [250 60 0.9];   
ub = [350 80 1.4];  

% populate initial starting vertices (6 vertices) k = 2n ; n=3 (number of parameters to be calibrated)

par_1=zeros(6,3);
for i=1:6
    par_o(i,:)=lb+rand(1,3).*(ub-lb);
end

% Model run
par=par_o;
max_int=300;       % maximum number of iteration    
Toler_=zeros(10,3);   % Counter check

RunVol_sim=zeros(1,6); % number of vertices / number of storms
PeakF_sim=zeros(1,6);
E=zeros(1,1);

for i=1:6 % for 6 different vertices      
        %i

          % Changing Subcatchment Area
          Data{1,1}{index3+1}(52:58)=sprintf('%6.4f',par(i,1)); (This part was the error)

          % Changing % impervious     
          Data{1,1}{index3+2}(59:61)=sprintf('%2f',par(i,2));       

          % Changing Subcatchment width range
          Data{1,1}{index3+4}(62:67)=sprintf('%5.2f',30.72*par(i,3));

In the command window, it shows,

??? In an assignment  A(:) = B, the number of elements in A and B
must be the same.

Error in ==> Tbftest at 60
        Data{1,1}{index3+1}(52:58)=sprintf('%6.4f',par(i,1));** *

Its my first time using MATLAB and my seniors doesn't know how to handle this as well. I really appreciate anyone's help on this.

Answer 1

[Iain]

Ick. Data is a cell array that contains a cell array that contain arrays.

 Data{1,1}{index3+1}(52:58) is 7 characters long. 
 sprintf('%6.4f',par(i,1)); is a different length. It is at least 6 characters long.

Obviously, you can't fit 6, 8, 9 or 10 characters in a 7 character long space, so you need to adapt either the space you're sticking it in, or change what you're trying to stick in.

 string_to_add =  sprintf('%6.4f',par(i,1)); 
 length_of_string = numel( string_to_add);
 Data{1,1}{index3+1}(52:(52+length_of_string-1)) = string_to_add;

That'll get rid of the error, but not necessarily fix what the problem is.

[Jevy]

Thank you very much. It worked! =D

Answer 2

[Walter Roberson]

52:58 is seven locations, but your 6.4f format is producing six characters.