Number generator for 0.00006 to 30 range

I am attempting to run monte carlo simulations and wanted a random number between the end members of 0.000069 and 30 to populate this equation through each pass of a for loop. After looking at my model's output, I noticed that the Kd is heavily skewed toward larger numbers. I then came across this thread which led me to read about creating one's own random number stream. Is there a number generator out there that gives equal weight to each order of magnitude...ie I'd like the number generator to be equally likely to draw .0005, .05, 5, etc. Originally I didn't realize that unifrnd was not appropriate for 0 to 1 range. Thank you in advance for any guidance.

Kd=unifrnd(0.000069,30);

Answer 1

[weikang zhao]

It looks like you don't want these random numbers to follow a uniform distribution, you want their logarithms to follow a uniform distribution.

try this way:

a=log10(0.000069);

b=log10(30);

Kd=10^(unifrnd(a,b));

Answer 2

[Chunru]

% Kd=unifrnd(0.000069,30);
logminmax = log10([0.000069,30]);
for i=1:20
    kdlog = unifrnd(logminmax(1), logminmax(2));
    kd = 10^kdlog
end

kd = 0.0017

kd = 2.5985e-04

kd = 0.0066

kd = 0.0038

kd = 1.3455e-04

kd = 9.1956e-05

kd = 0.0160

kd = 0.0231

kd = 0.0272

kd = 3.1372e-04

kd = 0.0571

kd = 2.5811

kd = 0.1905

kd = 0.0177

kd = 0.1814

kd = 1.7050

kd = 0.1131

kd = 0.2859

kd = 0.8698

kd = 3.1837e-04