Question

I’d like to generate a random number in a certain interval using an exponential distribution. My problem is that if I use exprnd I can’t control the interval, I can only give a mean value, but that doesn’t suit my needs.
Is there another function or is there some trick that I have to use?

Answer 1

Does this help? (or have I misunderstood the problem?)

%#Set the parameters
T = 2000; %#Number of observations to simulate
Mu = 0.5; %#Exponential distribution parameter
LB = 0; %#Lower bound on exponential distribution
UB = 1; %#Upper bound on exponential distribution

%#Validate the parameters
if LB < 0 || UB < 0; error('Bounds must be non-negative'); end
if Mu <= 0; error('Mu must be positive'); end

%#Determine LB and UB in terms of cumulative probabilities
LBProb = expcdf(LB, Mu);
UBProb = expcdf(UB, Mu);

%#Simulate uniform draws from the interval LBProb to UBProb
Draw = LBProb + (UBProb - LBProb) .* rand(T, 1);

%#Convert the uniform draws to exponential draws using the inverse cdf
X = expinv(Draw, Mu);