Clutter (software)

Clutter is a GObject-based graphics library for creating hardware-accelerated user interfaces. Clutter is an OpenGL-based 'interactive canvas' library and does not contain any graphical control elements. It relies upon OpenGL (1.4+) or OpenGL ES (1.1 or 2.0) for rendering,. It also supports media playback using GStreamer and 2D graphics rendering using Cairo.

Clutter was authored by OpenedHand Ltd, now part of Intel. Clutter is free and open-source software, subject to the requirements of the GNU Lesser General Public License (LGPL), version 2.1.

Adoption

Popular programs that adopt Clutter are GNOME Videos (a.k.a Totem), GNOME Shell, Pitivi, Cinnamon Desktop and GNOME Ease.

Mx is a widget toolkit based on Clutter originally designed for the graphical shell of Moblin/MeeGo netbook, but evolved into an independent project.

The widget toolkits Netbook Toolkit (nbtk) and Mx are based on Clutter. Often Clutter is seen analogous to GTK+ but this is inaccurate. Only Clutter together with Mx or Nbtk can match the extent of the GTK+. This is also the reason why Clutter is used together with GTK+.

Software

Computer software also called a program or simply software is any set of instructions that directs a computer to perform specific tasks or operations. Computer software consists of computer programs, libraries and related non-executable data (such as online documentation or digital media). Computer software is non-tangible, contrasted with computer hardware, which is the physical component of computers. Computer hardware and software require each other and neither can be realistically used without the other.

At the lowest level, executable code consists of machine language instructions specific to an individual processor—typically a central processing unit (CPU). A machine language consists of groups of binary values signifying processor instructions that change the state of the computer from its preceding state. For example, an instruction may change the value stored in a particular storage location in the computer—an effect that is not directly observable to the user. An instruction may also (indirectly) cause something to appear on a display of the computer system—a state change which should be visible to the user. The processor carries out the instructions in the order they are provided, unless it is instructed to "jump" to a different instruction, or interrupted.

Software (novel)

Software is a 1982 cyberpunk science fiction novel written by Rudy Rucker. It won the first Philip K. Dick Award in 1983. The novel is the first book in Rucker's Ware Tetralogy, and was followed by a sequel, Wetware, in 1988.

Plot summary

Software introduces Cobb Anderson as a retired computer scientist who was once tried for treason for figuring out how to give robots artificial intelligence and free will, creating the race of boppers. By 2020, they have created a complex society on the Moon, where the boppers developed because they depend on super-cooled superconducting circuits. In that year, Anderson is a pheezer — a freaky geezer, Rucker's depiction of elderly Baby Boomers — living in poverty in Florida and terrified because he lacks the money to buy a new artificial heart to replace his failing, secondhand one.

As the story begins, Anderson is approached by a robot duplicate of himself who invites him to the Moon to be given immortality. Meanwhile, the series' other main character, Sta-Hi Mooney the 1st — born Stanley Hilary Mooney Jr. — a 25-year-old cab driver and "brainsurfer", is kidnapped by a gang of serial killers known as the Little Kidders who almost eat his brain. When Anderson and Mooney travel to the Moon together at the boppers' expense, they find that these events are closely related: the "immortality" given to Anderson turns out to be having his mind transferred into software via the same brain-destroying technique used by the Little Kidders.

Software (development cooperation)

See also

Further reading

Clutter

Clutter may refer to any of the following:

Excessive physical disorder

Speech

Other

Clutter (radar)

Clutter is a term used for unwanted echoes in electronic systems, particularly in reference to radars. Such echoes are typically returned from ground, sea, rain, animals/insects, chaff and atmospheric turbulences, and can cause serious performance issues with radar systems.

Backscatter coefficient

What is considered to be clutter by one user may be a target for another. Usually targets may be considered to be a point scatterer and clutter as extended, covering many range, angle and Doppler cells. The clutter may fill a volume (rain) or be confined to a surface (land). In principle all that is required to estimate the return (backscatter) is a knowledge of the volume or surface illuminated and the echo per unit volume, η, or per unit surface area, σ°, (the backscatter coefficient).

Clutter-limited or noise-limited radar

In addition to any possible clutter there will also always be noise. The total signal competing with the target return is thus clutter plus noise. In practice there is often either no clutter or clutter dominates and the noise can be ignored. In the first case the radar is said to be Noise Limited, in the second it is Clutter Limited.

Sperner family

In combinatorics, a Sperner family (or Sperner system), named in honor of Emanuel Sperner, is a family of sets (F, E) in which none of the sets is contained in another. Equivalently, a Sperner family is an antichain in the inclusion lattice over the power set of E. A Sperner family is also sometimes called an independent system or a clutter.

Sperner families are counted by the Dedekind numbers, and their size is bounded by Sperner's theorem and the Lubell–Yamamoto–Meshalkin inequality. They may also be described in the language of hypergraphs rather than set families, where they are called clutters.

Dedekind numbers

The number of different Sperner families on a set of n elements is counted by the Dedekind numbers, the first few of which are

Although accurate asymptotic estimates are known for larger values of n, it is unknown whether there exists an exact formula that can be used to compute these numbers efficiently.

Bounds on the size of a Sperner family

Sperner's theorem

The k-element subsets of an n-element set form a Sperner family, the size of which is maximized when k = n/2 (or the nearest integer to it). Sperner's theorem states that these families are the largest possible Sperner families over an n-element set. Formally, the theorem states that, for every Sperner family S over an n-element set,