To induce sparseness into draws from the Dirichlet distribution we need the parameters of the Dirichlet distribution to be:

Question

BlackTom AI · Accepted Answer

The Dirichlet distribution is parameterized by a vector of concentration parameters α = (α1, α2, ..., αK). For sparseness in the draws, we typically want small concentration parameters, specifically αi in the range (0, 1). This causes the distribution to place more mass on vectors where only a few components are large and the rest are near zero, creating sparse probability allocations.

Option 1: non-negative. While αi being non-negative (i.e., αi ≥ 0) is a necessary relaxation in some contexts, the Dirichlet parameters must actually be strictly positive (αi > 0). If any αi = 0, the distribution is not well-defined or degenerates, so this is not the precise requirement for inducing sparseness.

Option 2: between 0 and 1. This correctly captures the common regime used to promote sparsity in Dirichlet draws, since αi ∈ (0, 1) biases mass toward extreme coordinates, yielding sparse outcomes.

Option 3: sum to 1. The constraint that the components of a Dirichlet-distributed vector sum to 1 is a property of the draw Y ~ Dirichlet(α), not a property of the α parameters themselves. The α parameters do not need to sum to 1; instead, they can be any positive values, and the resulting draw will automatically have components summing to 1. This choice describes the output space, not the parameter values that control sparseness.

In summary, to encourage sparsity in samples from Dirichlet(α), we typically choose αi in the (0, 1) interval, which fosters concentration on few components while keeping the overall draw valid.

To induce sparseness into draws from the Dirichlet distribution we need the parameters of the Dirichlet distribution to be:单项选择题

类似问题

The distribution of words in a topic is a draw from the Dirichlet distribution:

The Dirichlet distribution is best described as the distribution of …. (choose one best answer):

Name the Supreme Court decision that removed financial constraints on PACs.

Political scientists Joshua Kalla and David Broockman find that senior policy makers made themselves available to _____ between three and four times more often than they did to constituents.

Name the political scientist who argues that parties are designed to serve the needs of ambitious politicians (namely candidates and officeholders).

Name the political scientist who said this famous quote about the problems of pluralism: “The flaw in the pluralist heaven is that the heavenly choir sings with a strong upper-class accent.”

What is the name of the third party candidate in 2000 who was not allowed to participate in the presidential debates? Hint: We watched a video clip with him in class.

E.E. Schattshneider said, "Democracy is ________ save in terms of the parties."

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单