19. The computer-readable storage media of claim 18 , wherein performing the plurality of sampling iterations comprises performing a respective portion of the sampling independently on each of multiple processors, and wherein each processor p calculates an update ΔC |p WT and an update ΔC |p TC , and C k,c TC and C v,k WT are updated according to the expressions C WT += ∑ p = 1 P ⁢ Δ ⁢ ⁢ C | p WT and C TC += ∑ p = 1 P ⁢ Δ ⁢ ⁢ C | p TC .
19. The computer-readable storage media of claim 18 , wherein performing the plurality of sampling iterations comprises performing a respective portion of the sampling independently on each of multiple processors, and wherein each processor p calculates an update ΔC |p WT and an update ΔC |p TC , and C k,c TC and C v,k WT are updated according to the expressions C WT += ∑ p = 1 P ⁢ Δ ⁢ ⁢ C | p WT and C TC += ∑ p = 1 P ⁢ Δ ⁢ ⁢ C | p TC . 20. The computer-readable storage media of claim 19 , where conditional probabilities satisfy the expressions: P ⁡ ( z = k | u = c ) = C k , c TC + α ∑ k ′ ⁢ C k ′ , c TC + K ⁢ ⁢ α ; P ⁡ ( w = v | z = k ) = C v , k W ⁢ ⁢ T + β ∑ v ′ ⁢ C v ′ , k WT + V ⁢ ⁢ β ; P ⁡ ( u = c | z = k ) = C k , c TC + α ∑ c ′ ⁢ C k , c ′ TC + C ⁢ ⁢ α ; and P ⁡ ( z = k | w = v ) = C v , k WT + β ∑ k ′ ⁢ C v , k WT + K ⁢ ⁢ β .