Space Time Hierachy
Last edited: August 8, 2025I finally get to sound like I’m doing physics.
\begin{equation} L \subseteq P \subseteq \text{PSPACE} \subseteq \text{EXP} \end{equation}
by space hierarchy theorem and time hierarchy theorem, we have also that:
\begin{equation} \text{P} \subset \text{EXP} \end{equation}
and
\begin{equation} L \subset\text{PSPACE} \end{equation}
so we know that one of the subset things on top is a strict subset. There’s also a bridge \(P \subseteq \text{NP} \subseteq \text{PSPACE}\).
\(L =^{?} P\)
We believe that \(L \subset P\), but we can’t show this.
span (linear algebra)
Last edited: August 8, 2025The span of a bunch of vectors is the set of all linear combinations of that bunch of vectors. We denote it as \(span(v_1, \dots v_{m)}\).
constituents
- for constructing a linear combination
requirements
\begin{equation} span(v_{1}..v_{m}) = \{a_1v_1+\dots +a_{m}v_{m}:a_1\dots a_{m} \in \mathbb{F}\} \end{equation}
additional information
span is the smallest subspace containing all vectors in the list
Part 1: that a span of a list of vectors is a subspace containing those vectors
spanish
Last edited: August 8, 2025- Órale pues: confirmando
- No hay pedo: no hay problema
- Ponte la de puebla: dividirlo
- Qué padre: sopresa positiva
- De a grapa: gratis
- De poca madre: júbilo y aceptación
- Te vas a dar un ranazo: nos vamos a hacer daño (hurt)
Mamá: ¡necesitamos limpiar sus cuartos! Me: órale pues, no hay pedo. Voy a limpiarlo mañana.
Mi plan está simple. Voy a dividir mi cuarto a media, y contrata mi amiga para ayudarme. ¡Ponte la de puebla!
Spark
Last edited: August 8, 2025Spark is not a database. Importantly, its a “framework” of data:
- Programming platform
- Distributed file system
- Prallel execution environment
- Software ecosystem
It gives you the “parallel” search/sort needed to navigate a large database. It is based on the Hadoop ecosystem. Spark operates on RDDs to do lazy-evaluation.
Quickstart
When we start up Spark Shell, it will build you a sc
variable which is appropriate for your supercomputer; if you are not, you need to set up the context yourself using the 3 lines noted below to make sc
variable:
Sparse Sampling
Last edited: August 8, 2025Same core algorithm as Forward Search, but instead of calculating a utility based on the action-value over all possible next states, you make \(m\) different samples of next state, action, and reward, and average them