code that randomly changes columns in matrix throws error

I have a matrix

This matrix consists of four rows. Some numbers are integers and some are decimals. I want to print a code on this matrix, but it gives an error like this:

Error using randperm

Size inputs must be integers.

Error in deneme (line 49)

new_idx = randperm(size(D,2)/2)*2-[1; 0];

>>

My code is :

new_idx = randperm(size(D,2)/2)*2-[1; 0];
rassalnew= D(:,new_idx(:))

What can I do to fix this problem?

Thank for help

D matrix:

1 2 3 4

510.090000000000 26.4600000000000 22.3400000000000 188.300000000000

510.090000000000 26.4600000000000 22.3400000000000 169.680000000000

510.090000000000 26.4600000000000 22.3400000000000 188.300000000000

Answer 1

[Voss]

It seems to be working for that matrix D:

D = [ ...
    1                   2	                3	                4
    510.090000000000	26.4600000000000	22.3400000000000	188.300000000000
    510.090000000000	26.4600000000000	22.3400000000000	169.680000000000
    510.090000000000	26.4600000000000	22.3400000000000	188.300000000000];

new_idx = randperm(size(D,2)/2)*2-[1; 0];
rassalnew= D(:,new_idx(:))

rassalnew = 4×4

3.0000 4.0000 1.0000 2.0000 22.3400 188.3000 510.0900 26.4600 22.3400 169.6800 510.0900 26.4600 22.3400 188.3000 510.0900 26.4600

But you will get that error if D has an odd number of columns:

D = [ ...
    0       1                   2	                3	                4
    300     510.090000000000	26.4600000000000	22.3400000000000	188.300000000000
    400     510.090000000000	26.4600000000000	22.3400000000000	169.680000000000
    200     510.090000000000	26.4600000000000	22.3400000000000	188.300000000000];
new_idx = randperm(size(D,2)/2)*2-[1; 0];

Error using randperm
Size inputs must be integers.

rassalnew= D(:,new_idx(:))

[Berfin Çetinkaya]

This is a big matrix in original. so I can't manually enter the first line. How can I convert it to 1.000?

[Voss]

Sorry, I don't understand what you mean by, "manually enter the first line" or "convert it to 1.000". Can you please explain?

I should emphasize that the error happens whenever D has an odd number of columns, and the error has nothing to do with the contents of D (e.g., it does not matter whether the elements are integers or not). The assumption in using randperm() to rearrange the columns in pairs is that there are an even number of columns.

[Berfin Çetinkaya]

I understand what you mean now. Thank you for your help

[Berfin Çetinkaya]

If I wanted to randomly change the columns one by one, how should I do it? could i use randperm?

[Voss]

You're welcome!

Yes, you can use randperm() for that:

D = [ ...
    1                   2	                3	                4
    510.090000000000	26.4600000000000	22.3400000000000	188.300000000000
    510.090000000000	26.4600000000000	22.3400000000000	169.680000000000
    510.090000000000	26.4600000000000	22.3400000000000	188.300000000000];
new_idx = randperm(size(D,2));
rassalnew= D(:,new_idx(:))

rassalnew = 4×4

3.0000 2.0000 1.0000 4.0000 22.3400 26.4600 510.0900 188.3000 22.3400 26.4600 510.0900 169.6800 22.3400 26.4600 510.0900 188.3000

[Berfin Çetinkaya]

Thanks a lot of :)

[Voss]

You're welcome!