Changing elements in a MxN matrix

Question

WARRIOR24 2021-4-20

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/807137-changing-elements-in-a-mxn-matrix

编辑： per isakson 2021-4-20

I am trying to get zeros for certain part of a Matrix to zeros

I need this matrix ones that are bolded, underlines, italic "1" to become zeros. I have been trying to figure this out for a while. I tried if statesments for row > 5 and for loops.

4 1 0 1 0 1 0 1 0 1

1 4 1 0 1 0 1 0 1 0

0 1 4 1 0 1 0 1 0 1

1 0 1 4 1 0 1 0 1 0

0 1 0 1 4 1 0 1 0 1

1 0 1 0 1 4 1 0 1 0

0 1 0 1 0 1 4 1 0 1

1 0 1 0 1 0 1 4 1 0

0 1 0 1 0 1 0 1 4 1

1 0 1 0 1 0 1 0 1 4

Here is my code:

inverse = diag(ones(10,1));
inverse = inverse*4;
for col = 1:length(domain-1)
    for row = 1:10
       if row == col
            inverse(row+1,col) = 1;
            inverse(row,col+1) = 1;
       
       elseif mod(row+col,2) == 1
            inverse(row,col) = 1;
       end
    end
end
matrix = inverse(Nx-1,Ny-1)

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Answer 1

per isakson 2021-4-20

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/807137-changing-elements-in-a-mxn-matrix#answer_679497

编辑：per isakson 2021-4-20

在 MATLAB Online 中打开

Does this help?

%%
matrix  = magic(10);
matrix = triu( matrix,-4 );
matrix = tril( matrix, 4 )
matrix = 10×10
    92    99     1     8    15     0     0     0     0     0
    98    80     7    14    16    73     0     0     0     0
     4    81    88    20    22    54    56     0     0     0
    85    87    19    21     3    60    62    69     0     0
    86    93    25     2     9    61    68    75    52     0
     0    24    76    83    90    42    49    26    33    65
     0     0    82    89    91    48    30    32    39    66
     0     0     0    95    97    29    31    38    45    72
     0     0     0     0    78    35    37    44    46    53
     0     0     0     0     0    36    43    50    27    59
%% This is better, it only overwrites the specific diagonals
matrix  = magic(10);
for k = [5,7,9]
    isdiag = diag( true(10-k,1), k );
    matrix( isdiag ) = 0;
    isdiag = diag( true(10-k,1), -k );
    matrix( isdiag ) = 0;
end
matrix
matrix = 10×10
    92    99     1     8    15     0    74     0    58     0
    98    80     7    14    16    73     0    57     0    41
     4    81    88    20    22    54    56     0    70     0
    85    87    19    21     3    60    62    69     0    28
    86    93    25     2     9    61    68    75    52     0
     0    24    76    83    90    42    49    26    33    65
    23     0    82    89    91    48    30    32    39    66
     0     6     0    95    97    29    31    38    45    72
    10     0    94     0    78    35    37    44    46    53
     0    18     0    77     0    36    43    50    27    59