Rate-distortion function for gamma sources under absolute-log distortion measure

We evaluate the rate-distortion function for the i.i.d. gamma sources with respect to the absolute-log distortion measure. The logarithmic transformation reduces this rate-distortion problem to that under the absolute distortion measure. Extending the explicit evaluation of the rate-distortion function for the Gaussian sources, we obtain the parametric form of the rate-distortion function. We show that the optimal distribution of reconstruction consists of a continuous component enclosed by left and right discrete components and the left discrete component vanishes when the allowed distortion is small.