Charm

Charm or charms, or The Charm, originally from Latin carmen ("song"), may refer to:

Common meanings

People

Geography

Business

Science and computing

Charm++

Charm++ is a parallel object-oriented programming language based on C++ and developed in the Parallel Programming Laboratory at the University of Illinois. Charm++ is designed with the goal of enhancing programmer productivity by providing a high-level abstraction of a parallel program while at the same time delivering good performance on a wide variety of underlying hardware platforms. Programs written in Charm++ are decomposed into a number of cooperating message-driven objects called chares. When a programmer invokes a method on an object, the Charm++ runtime system sends a message to the invoked object, which may reside on the local processor or on a remote processor in a parallel computation. This message triggers the execution of code within the chare to handle the message asynchronously.

Chares may be organized into indexed collections called chare arrays and messages may be sent to individual chares within a chare array or to the entire chare array simultaneously.

The chares in a program are mapped to physical processors by an adaptive runtime system. The mapping of chares to processors is transparent to the programmer, and this transparency permits the runtime system to dynamically change the assignment of chares to processors during program execution to support capabilities such as measurement-based load balancing, fault tolerance, automatic checkpointing, and the ability to shrink and expand the set of processors used by a parallel program.

Greeks (finance)

In mathematical finance, the Greeks are the quantities representing the sensitivity of the price of derivatives such as options to a change in underlying parameters on which the value of an instrument or portfolio of financial instruments is dependent. The name is used because the most common of these sensitivities are denoted by Greek letters (as are some other finance measures). Collectively these have also been called the risk sensitivities,risk measures or hedge parameters.

Use of the Greeks

The Greeks are vital tools in risk management. Each Greek measures the sensitivity of the value of a portfolio to a small change in a given underlying parameter, so that component risks may be treated in isolation, and the portfolio rebalanced accordingly to achieve a desired exposure; see for example delta hedging.

The Greeks in the Black–Scholes model are relatively easy to calculate, a desirable property of financial models, and are very useful for derivatives traders, especially those who seek to hedge their portfolios from adverse changes in market conditions. For this reason, those Greeks which are particularly useful for hedging—such as delta, theta, and vega—are well-defined for measuring changes in Price, Time and Volatility. Although rho is a primary input into the Black–Scholes model, the overall impact on the value of an option corresponding to changes in the risk-free interest rate is generally insignificant and therefore higher-order derivatives involving the risk-free interest rate are not common.

Pile

Pile may refer to:

Energy

Architecture

Data processing

People

Places

Nuclear reactor

A nuclear reactor, formerly known as an atomic pile, is a device used to initiate and control a sustained nuclear chain reaction. Nuclear reactors are used at nuclear power plants for electricity generation and in propulsion of ships. Heat from nuclear fission is passed to a working fluid (water or gas), which runs through turbines. These either drive a ship's propellers or turn electrical generators. Nuclear generated steam in principle can be used for industrial process heat or for district heating. Some reactors are used to produce isotopes for medical and industrial use, or for production of weapons-grade plutonium. Some are run only for research. Today there are about 450 nuclear power reactors that are used to generate electricity in about 30 countries around the world.

Mechanism

Just as conventional power-stations generate electricity by harnessing the thermal energy released from burning fossil fuels, nuclear reactors convert the energy released by controlled nuclear fission into thermal energy for further conversion to mechanical or electrical forms.

Pile (abstract data type)

In computer science, a pile is an abstract data type for storing data in a loosely ordered way. There are two different usages of the term; one refers to an ordered deque, the other to an improved heap.

Ordered deque

The first version combines the properties of the deque and a priority queue and may be described as an ordered deque.

An item may be added to the head of the list if the new item is valued less than or equal to the current head or to the tail of the list if the new item is greater than or equal to the current tail. Elements may be removed from both the head and the tail.

Piles of this kind are used in the "UnShuffle sort" sorting algorithm.

Improved heap

The second version is a subject of patents and improves the heap data structure.

The whole Data Pile-based system can be generalized as shown:

References