An efficient and easily parallelizable algorithm for pricing weather derivatives

We present a fast and highly parallel algorithm for pricing CDD weather derivatives, which are financial products for hedging weather risks due to higher-than average temperature in summer. To find the price, we need to compute the expected value of its payoff, namely, the CDD weather index. To this end, we derive a new recurrence formula to compute the probability density function of the CDD. The formula consists of multiple convolutions of functions with a Gaussian distribution and can be computed efficiently with the fast Gauss transform. In addition, our algorithm has a large degree of parallelism because each convolution can be computed independently. Numerical experiments show that our method is more than 10 times faster than the conventional Monte Carlo method when computing the prices of various CDD derivatives on one processor. Moreover, parallel execution on a PC cluster with 8 nodes attains up to six times speedup, allowing the pricing of most of the derivatives to be completed in about 10 seconds.