How can I get randperm function to calculate assigned percentage and values?

조회 수: 1 (최근 30일)
종현 김 2022년 6월 30일
답변: Steven Lord 2022년 6월 30일
I need to calculate that out of 1000000 elements, 75% should be randomly assigned a value of 1.5.
‘p = randperm(n)’ to specify which element is assigned with the properties of inclusions, where ‘n’ is the total number of elements (1000000), ‘p’ contains randomly ordered numbers from ‘1’ to ‘n’. Then, I need to assign the first ‘m’ elements with the value (1.5)
Out of 1000000 elements, 75% should be randomly assigned a value of 1.5.
‘n’=1000000
‘m’=1.5

댓글을 달려면 로그인하십시오.

채택된 답변

Keshav 2022년 6월 30일
Based on my understanding, you want to generate an array of size n such that random 75% elements value is 1.5.
you can use the below code to do so.
n = 1000000;
p = randperm(n);
array = zeros(n,1);
num = .75*n;
for i = 1:num
array(p(i)) = 1.5;
end
% if you want you can assign some other value to the remaining elements
%for i = num+1:n
% array(p(i)) = some_other_val
%end

댓글을 달려면 로그인하십시오.

추가 답변 (1개)

Steven Lord 2022년 6월 30일
Let's look at a slightly smaller problem.
A = zeros(10);
numElements = numel(A)
numElements = 100
numDesired = ceil(0.25*numElements)
numDesired = 25
elementsToSet = randperm(numElements, numDesired)
elementsToSet = 1×25
80 78 77 26 7 38 96 65 99 57 14 15 42 10 81 86 8 51 90 30 1 22 47 33 62
A(elementsToSet) = 1
A = 10×10
1 0 0 0 0 1 0 0 1 0 0 0 1 0 1 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 1 1 0 0 0 1 1 0 1 0 0 1 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1 0 0 0 0 1 1 0
howManyNonzeroElements = nnz(A) % Should be numDesired
howManyNonzeroElements = 25
Alternately if you're working with sparse matrices you should look at sprand, sprandn, and sprandsym instead.

댓글을 달려면 로그인하십시오.

카테고리

Help CenterFile Exchange에서 Sparse Matrices에 대해 자세히 알아보기

R2020b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by