How to generate a random matrix with a constraint or step range ?

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Varun Pai
Varun Pai 2020-4-23
评论： Varun Pai 2020-4-23
I want to generate a Nx4 random matrix. In this matrix, each column is considered having different range and step. The random values should be only from these steps.
For e.g. 1st column 0:0.1:1
2nd column > 0:1:10
3rd column > 2:0.5:8
4th column > 0:-1:-10
I want to generate a random matrix of N=5. I should get a matrix with above conditions. Like this
[0 5 3.5 -5 ;
0.8 8 7 -3
0.2 0 2.5 -7
0.6 8 6.5 0
0.9 3 7.5 -9]
The N value could go to any size. Repeated values are permissible. I tried some random functions like randperm, randsample etc but I am not able to produce like this. Randperm is not allowing to produce repeated values.
How could I generate it ? Could you help with a code sample ?

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KSSV
KSSV 2020-4-23
编辑：KSSV 2020-4-23
Read about randsample, randperms.
C1 = 0:0.1:1 ;
C2 = 0:1:10 ;
C3 = 2:0.5:8 ;
C4 = 0:-1:-10 ;
N = 5 ; M = 4 ;
C = zeros(N,M) ;
C(:,1) = randsample(C1',5) ;
C(:,2) = randsample(C2',5) ;
C(:,3) = randsample(C3',5) ;
C(:,4) = randsample(C4',5) ;
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KSSV
KSSV 2020-4-23
编辑：KSSV 2020-4-23
You split the big number into multiples and pick from each column.
You can use repmat on C1, repeat the values and pick them at once.
Varun Pai
Varun Pai 2020-4-23
That's great... Thank you for the suggestion.
function ParameterSet = GenerateRandomSet(MinVal,MaxVal,StepVal,N)
% MinVal : 1 x M array of Lower limit
% MaxVal : 1 x M array of Upper limit
% StepVal : 1 x M array of Step values
% N : ParameterSet row size
% Usage eg. GenerateRandomSet([0 0 2 0],[1 10 8 -10],[0.1 1 0.5 -1],50)
rows = N;
cols = length(MinVal);
ParameterSet = zeros(rows,cols);
for c = 1:cols
ParamVectors = MinVal(c):StepVal(c):MaxVal(c);
repfactor = floor(N/length(ParamVectors)) + 1;
ParamVectors = repmat(ParamVectors,1,repfactor);
ParameterSet(:,c) = randsample(ParamVectors',N);
end
end

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更多回答（1 个）

madhan ravi
madhan ravi 2020-4-23
Hint example:
x = 1:10;
N = 5;
x(randi(numel(x),1,N))

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