Could anyone help me to fix the issue.

If A=rand(5,10) how to have the values by fixing the minimum value to be 0.01 and maximum value to be 0.09 and by adding all the random values together it should result in 0.35. For example I have taken the minimum value and maximum value to be 0.01 and 0.09. And the addition of all the values should result in 0.35.Could anyone help me how to implement it.

[John D'Errico]

Why do you feel it necessary to ask the same question always at least TWICE, and often 3 or 4 times? You got an answer several times, with several ways to do it.

You have now asked something over 170 basic questions, and as has been pointed out, do not seem to be learning the basics of MATLAB yet. Surely it it time to read the documentation, rather than relying on Answers as your lazy manual? In this case, had you simply done a search on answers, you would have found the same question asked and answered repeatedly.

[Stephen23]

See version number five:

https://www.mathworks.com/matlabcentral/answers/379141-could-anyone-help-me-to-solve-the-issue-in-the-following-code

Answer 1

[Birdman]

One way:

a=0.01;b=0.09;N=10;
while true
    A=a+(b-a).*rand(N,1)
    if ismembertol(sum(A(:)),0.35,1e-2)
        break;
    else
    end
end

[Prabha Kumaresan]

I have modified the code which you have answered as i am having a matrix size of (n,m).
If i run the following code i am unable to get the output.It keeps on running.
Could you please help me to check whether the code was correct.
a=0.01;
b=0.09;
B=rand(2,2)
while true
    A=a+(b-a).*B
    if ismembertol(sum(A(:)),0.35)
break;
else
end
end

[Walter Roberson]

When you write lines of description of your code, such as your "I have modified the code" above, then those lines should not have any leading spaces on the line.

Put an empty line between your description of the code and your code.

Each line of your code should start with at least one space. If you highlight your code with the mouse and click on {} Code then the system will automatically intent it for you.

If you have commentary after your code, put an empty line between your code and the commentary (and make sure the commentary does not start with spaces on the line.)

[Walter Roberson]

Your code does not change a or b or B inside the loop, so it will never exit the while loop.

[Prabha Kumaresan]

ok.could you please help me how to have the sum of the (n,m) array having random number of values within the range of [min(0.01),max(0.09)]to a fixed value.

[Birdman]

a=0.01;b=0.09;n=2;m=2;
while true
    A=a+(b-a).*rand(n,m)
    if ismembertol(sum(A(:)),0.35,1e-2)
        break;
    else
    end
end

[Walter Roberson]

Birdman's solution could execute for a long time. It is recommended that you used randfixedsum like Stephen recommended.

[Birdman]

Yes, as I said, it is one way of solving the problem.

[Prabha Kumaresan]

ok.but randfixedsum was subject to the condition that their sum of array should be equal to s.But for me it will not be equal.I would like to check with the following code:

code:

s=[2 2;
    2 2]
if ismembertol(sum(s(:)),12,1e-4)
 break;
  else
  end

If i run the code i am getting ismembertol(sum(s(:)),12,1e-4) is 0.could you tell mehow to get 1 for the ismembertol.

[Birdman]

a=0.01;b=0.09;n=2;m=2;
while true
    A=a+(b-a).*rand(n,m)
    if ismembertol(sum(A(:)),0.35,1e-2)
        break;
    else
    end
end

This solution works. Why don't you run it?

[Walter Roberson]

randfixedsum makes the sum of the random vector into whatever value you tell it to use. You would tell it the sum needed to be 0.35 and you would tell it the total number of elements m*n, and the lower bound 0.01 and the upper bound 0.09, and it would generate a vector for you. You would then reshape that vector to the correct number of rows and columns.

[Prabha Kumaresan]

I would like to check the code

a=0.01;b=0.09;n=2;m=2;
while true
    A=a+(b-a).*rand(n,m)
    if ismembertol(sum(A(:)),0.35,1e-2)
        break;
    else
    end
end

the code executes if m and n are 2. but for the same code if i change the value of m and n to 4 it keeps on running.how should i need to check it.

[Stephen23]

@Prabha Kumaresan: why are you wasting your time on this? I showed you a working solution.

[Jan]

@Prabha: Birdman's code produced random numbers until the sum has the wanted value accidentally. You see that this takes a long time for 16 numbers. Note that this solution accepts a sum, which is not exactly 0.35, but uses a tolerance of 0.01 . For a reliable working code see Stephen's answer.

Answer 2

[Stephen23]

"If A=rand(5,10) how to have the values by fixing the minimum value to be 0.01 and maximum value to be 0.09 and by adding all the random values together it should result in 0.35"

This is impossible: matrix A has size 5x10 with 5*10=50 elements, which means that the minimum possible sum of all of its values will be 0.01*50=0.5, which is greater than the requested sum of 0.35.

Once you select values or a matrix size that are actually possible, then the simplest solution is to download and use Roger Stafford's excellent randfixedsum:

https://www.mathworks.com/matlabcentral/fileexchange/9700-random-vectors-with-fixed-sum

Here is a complete working example for a more realistic matrix size of 2x10:

>> r = 2;
>> c = 10;
>> [x,v] = randfixedsum(r*c,1,0.35,0.01,0.09);
>> y = reshape(x,r,c)
y =
   0.018153   0.011913   0.025947   0.020434   0.010300   0.027032   0.017784   0.018632   0.025201   0.015418
   0.014428   0.013693   0.012165   0.012403   0.026608   0.015631   0.013894   0.012895   0.014529   0.022941
>> sum(y(:))
ans =  0.35000

[Prabha Kumaresan]

ok.I have done the code with respect to the example;

code:

a=0.01
b=0.09
r = 2; c = 10;
[x,v] = randfixedsum(r*c,a,b,0.35);

------------------------------
function [x,v] = randfixedsum(r*c,a,b,0.35)
y = reshape(x,r,c)
v=sum(y(:))

If I run it I am getting Error: File: randfixedsum.m Line: 1 Column: 32 Unexpected MATLAB operator.

Error in [x,v] = randfixedsum(r*c,1,a,b,0.35); could you please help me to solve it.

[Walter Roberson]

Remove the two lines

------------------------------
function [x,v] = randfixedsum(r*c,a,b,0.35)

[Prabha Kumaresan]

after removing the two lines

------------------------------

function [x,v] = randfixedsum(r*c,a,b,0.35)

I have the following code:

a=0.01
b=0.09
r = 2; c = 10;
[x,v] = randfixedsum(r*c,a,b,0.35);
y = reshape(x,r,c)
v=sum(y(:))

When i run this i am still getting Error in [x,v] = randfixedsum(r*c,a,b,0.35);

[Stephen23]

@Prabha Kumaresan: what is the point of this?:

function [x,v] = randfixedsum(r*c,a,b,0.35)
y = reshape(x,r,c)
v=sum(y(:))

Did you see any functions defined anywhere in my answer? You do not need to define randfixedsum because it is a function that you need to download from the link that I gave in my answer. Did you download it?

You need to read my answer again. It tells you to download a function from the link that I gave. You need to download that function. Then the code I showed you will work. You do not need to guess, invent, change, make up, create, alter, adapt, or change my answer to make it work.

The function I linked to is very well written and you are just wasting your time not using it.

[Prabha Kumaresan]

but there is no option to accept the answer.

[Rik]

There is no option, because you have accepted another answer. You can only accept one answer per question, so if you want to accept this one, you will have to un-accept the other answer.

[Prabha Kumaresan]

ok.Whos answer do i need to unaccept so that i can accept stephen answer

[Rik]

The only other answer in thread: the one from Birdman, which you will find between this answer and your question.