Using while loops in matrices

Question

Olabayo 2022-12-17

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1880352-using-while-loops-in-matrices

评论： Walter Roberson 2022-12-17

I am trying to use while loop to change the diagonal entries of a square matrix rand(10) to 1, and other entries to zero

This code below is changing the whole entries to 1, i am stucked.

m= 1:10
n= 1:10
A = rand(10)
B = size (A)
while m==n    
    A(m,n) = 1;
    if not (m==n)
        A(m,n) = 0;
    end 
    break
end 
A

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Torsten 2022-12-17

A = rand(10);

A = eye(10);

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Answer 1

Pin-Hao Cheng 2022-12-17

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1880352-using-while-loops-in-matrices#answer_1130247

在 MATLAB Online 中打开

Let me know if this is what you are looking for. Happy to answer any further questions!

A = rand(10)
A = 10×10
    0.1406    0.9234    0.5213    0.0271    0.2317    0.3967    0.3776    0.4847    0.3080    0.0222
    0.4363    0.4473    0.2888    0.3199    0.6071    0.3528    0.3311    0.5584    0.4040    0.2190
    0.2656    0.6738    0.6987    0.3731    0.8456    0.9905    0.1035    0.4882    0.4701    0.2163
    0.0655    0.9590    0.1978    0.6575    0.6074    0.2159    0.2553    0.3445    0.9210    0.6419
    0.8856    0.9335    0.8339    0.5396    0.2503    0.0700    0.4051    0.7461    0.3052    0.1634
    0.4934    0.4743    0.6264    0.2365    0.6042    0.4961    0.4183    0.7427    0.0465    0.3843
    0.2964    0.5497    0.6846    0.4194    0.2852    0.9456    0.7047    0.9608    0.4107    0.6736
    0.7785    0.3134    0.1016    0.5672    0.2764    0.7794    0.3809    0.2773    0.2288    0.1847
    0.6817    0.5795    0.6303    0.4710    0.6249    0.1779    0.3139    0.5706    0.5860    0.4254
    0.6862    0.1720    0.4387    0.9392    0.0916    0.3381    0.4475    0.3649    0.5224    0.7542
for m = 1:10        % loop through rows
    for n = 1:10    % loop through columns
        if m == n   % check if it's diagonal el
            A(m,n) = 1;
        else
            A(m,n) = 0;
        end
    end
end
A
A = 10×10
     1     0     0     0     0     0     0     0     0     0
     0     1     0     0     0     0     0     0     0     0
     0     0     1     0     0     0     0     0     0     0
     0     0     0     1     0     0     0     0     0     0
     0     0     0     0     1     0     0     0     0     0
     0     0     0     0     0     1     0     0     0     0
     0     0     0     0     0     0     1     0     0     0
     0     0     0     0     0     0     0     1     0     0
     0     0     0     0     0     0     0     0     1     0
     0     0     0     0     0     0     0     0     0     1

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Walter Roberson 2022-12-17

在 MATLAB Online 中打开

A = rand(10)
A = 10×10
    0.5267    0.0485    0.6881    0.0751    0.5088    0.9623    0.4144    0.0369    0.5932    0.1203
    0.0743    0.4432    0.1701    0.8212    0.2084    0.4752    0.3201    0.4127    0.1457    0.4379
    0.4294    0.8825    0.5937    0.8722    0.1412    0.2457    0.6319    0.1385    0.0125    0.1849
    0.1902    0.2588    0.2948    0.1180    0.3554    0.0058    0.1091    0.1462    0.6565    0.7121
    0.3901    0.4582    0.6801    0.5591    0.1280    0.3830    0.4597    0.2188    0.6096    0.7307
    0.7630    0.4357    0.6976    0.8166    0.7730    0.5614    0.6620    0.1153    0.8800    0.3424
    0.9485    0.5221    0.1301    0.3194    0.6058    0.7353    0.1995    0.8348    0.8918    0.8874
    0.3259    0.7321    0.2832    0.4322    0.1251    0.5902    0.5059    0.1353    0.5748    0.5123
    0.2665    0.2283    0.9713    0.8249    0.1909    0.8411    0.5445    0.3293    0.1103    0.8057
    0.1126    0.5050    0.2498    0.4914    0.5326    0.4910    0.3327    0.8345    0.2003    0.1004
m = 1;
while m <= 10        % loop through rows
    n = 1;
    while n <= 10    % loop through columns
        if m == n   % check if it's diagonal el
            A(m,n) = 1;
        else
            A(m,n) = 0;
        end
        n = n + 1;
    end
    m = m + 1;
end
A
A = 10×10
     1     0     0     0     0     0     0     0     0     0
     0     1     0     0     0     0     0     0     0     0
     0     0     1     0     0     0     0     0     0     0
     0     0     0     1     0     0     0     0     0     0
     0     0     0     0     1     0     0     0     0     0
     0     0     0     0     0     1     0     0     0     0
     0     0     0     0     0     0     1     0     0     0
     0     0     0     0     0     0     0     1     0     0
     0     0     0     0     0     0     0     0     1     0
     0     0     0     0     0     0     0     0     0     1

Jan 2022-12-17

在 MATLAB Online 中打开

The pattern:

if m == n
    A(m,n) = 1;
else
    A(m,n) = 0;
end

can be abbreviated in general to:

A(m, n) = (m == n);

Walter Roberson 2022-12-17

The whole thing abbreviates to a call to eye() and size()

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Using while loops in matrices

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Using while loops in matrices

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