Editing Computer simulation (section)

{{short description|Process of mathematical modelling, performed on a computer}}
{{About|computer model within a scientific context|simulating a computer on a computer|emulator}}
{{redirect|Computer model|computer models of 3 dimensional objects|3D modeling}}
{{redirect|Digital model|virtual fictional characters|Virtual influencer}}
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[[File:Typhoon Mawar 2005 computer simulation thumbnail.gif|300px|thumb|A 48-hour computer simulation of [[2005 Pacific typhoon season#Typhoon Mawar|Typhoon Mawar]] using the [[Weather Research and Forecasting model]] ]]
[[File:Molecular simulation process.svg|400px|thumb|Process of building a computer model, and the interplay between experiment, simulation, and theory]]

'''Computer simulation''' is the running of a [[mathematical model]] on a [[computer]], the [[model]] being designed to represent the behaviour of, or the outcome of, a real-world or physical system. The reliability of some mathematical models can be determined by comparing their results to the real-world outcomes they aim to predict. Computer [[simulation]]s have become a useful tool for the mathematical modeling of many natural systems in [[physics]] ([[computational physics]]), [[astrophysics]], [[climatology]], [[chemistry]], [[biology]] and [[manufacturing]], as well as human systems in [[economics]], [[psychology]], [[social science]], [[health care]] and [[engineering]]. Simulation of a system is represented as the running of the system's model. It can be used to explore and gain new insights into new [[technology]] and to estimate the performance of systems too complex for [[analytical solution]]s.<ref>{{Cite book
  | last =Strogatz
  | first =Steven
  | contribution =The End of Insight
  | year =2007
  | title =What is your dangerous idea?
  | editor-last =Brockman
  | editor-first =John
  | publisher =HarperCollins
  | isbn=9780061214950
  }}</ref>

Computer simulations are realized by running [[computer program]]s that can be either small, running almost instantly on small devices, or large-scale programs that run for hours or days on network-based groups of computers. The scale of events being simulated by computer simulations has far exceeded anything possible (or perhaps even imaginable) using traditional paper-and-pencil mathematical modeling. In 1997, a desert-battle simulation of one force invading another involved the modeling of 66,239 tanks, trucks and other vehicles on simulated terrain around [[Kuwait]], using multiple supercomputers in the [[DoD]] High Performance Computer Modernization Program.<ref name="JPLsim">{{cite web |url-status=dead |url=http://www.jpl.nasa.gov/releases/97/military.html |title=Researchers stage largest Military Simulation ever |archive-url=https://web.archive.org/web/20080122123958/http://www.jpl.nasa.gov/releases/97/military.html |archive-date=2008-01-22 |website=[[Jet Propulsion Laboratory]] |publisher=[[Caltech]] |date=December 4, 1997}}</ref>
Other examples include a 1-billion-atom model of material deformation;<ref>{{cite web|title=Molecular Simulation of Macroscopic Phenomena|url=http://www.almaden.ibm.com/st/past_projects/fractures/ |website=IBM Research - Almaden |url-status=dead |archive-url=https://web.archive.org/web/20130522082737/http://www.almaden.ibm.com/st/past_projects/fractures/|archive-date=2013-05-22}}</ref> a 2.64-million-atom model of the complex protein-producing organelle of all living organisms, the [[ribosome]], in 2005;<ref name="LANLsim">{{cite web |last1= |first1= |date=December 2020 |title=Los Alamos National Laboratory has led the world in developing and using computer simulations to understand the world around us. |url=https://www.lanl.gov/media/publications/national-security-science/1220-the-computing-issue |url-status=live |archive-url=https://web.archive.org/web/20070704061957/http://www.lanl.gov/news/index.php/fuseaction/home.story/story_id/7428 |archive-date=2007-07-04 |publisher=[[Los Alamos National Laboratory]] |location=Los Alamos, NM}}</ref>
a complete simulation of the life cycle of ''[[Mycoplasma genitalium]]'' in 2012; and the [[Blue Brain]] project at [[EPFL]] (Switzerland), begun in May 2005 to create the first computer simulation of the entire human brain, right down to the molecular level.<ref name="Brainsim">{{cite web |url-status=live |url=https://www.newscientist.com/article/dn7470.html |title=Mission to build a simulated brain begins |archive-url=https://web.archive.org/web/20150209125048/http://www.newscientist.com/article/dn7470.html |archive-date=2015-02-09 |website=[[New Scientist]] |date=June 6, 2005 |first1=Duncan |last1=Graham-Rowe }}</ref>

Because of the computational cost of simulation, [[computer experiment]]s are used to perform inference such as [[uncertainty quantification]].<ref>{{cite book| author1=Santner, Thomas J| author2=Williams, Brian J| author3=Notz, William I| title=The design and analysis of computer experiments| year=2003| publisher=Springer Verlag}}</ref>