History of Scientific Computing! Topics to be addressed: Growth of compu5ng power Beginnings of Computa5onal Chemistry History of modern opera5ng system for scien5fic compu5ng: UNIX Current compu5ng power and what can be done with Computa5onal Chemistry The future of Computa5onal Chemistry
Developed for calcula/ons of ballis/c trajectories Programs were entered by hardwiring Beginnings of Compu5ng WW II - ENIAC (Electronic Numerical Integrator And Computer) Early History of Compu5ng: 1950s During this 5me: computers were expensive and difficult to use access was restricted (military use) MANIAC 1952 First program stored internally Used to design H bomb 2300 vacuum tubes
Early History of Compu5ng: 1950s UNIVAC 1951 Developed by Army, Census Bureau, NBS 43 total machines were produced 5000 vacuum tubes First magne/c tape storage The UNIVAC By the Mid to late 50s: Fewer than 1000 computers existed in US.
How Computa5onal Chemistry Began First Computa/onal Chemistry applica/on: University of Chicago Used UNIVAC at Wright AFB How Computa5onal Chemistry Began Bernard Ransil (U Chicago) Calcula/ons on diatomic molecules Performed in machine language Calcula/ons took 1 1/2 years to complete 12 diatomic molecule calcula/ons finished by late 1959 reasonable agreement achieved (1-2 sig figures) with experimental dipole moments, ioniza/on poten/als, etc.
Some of the Diatomic Molcules that Ransil Calculated H 2 HF LiH CO How Computa5onal Chemistry Began R. S. Mulliken - Nobel Prize 1966 for work on molecular orbital theory Mulliken summarized the use of computers in computa/onal chemistry to date: The opera5onal success of the computer program and the results it generated clearly heralded the dawn of a new era.
Compu5ng in the 1960s Important developments: Transistors replaced vacuum tubes. First mass- produced minicomputer (DEC PDP- 8) released in 1965. UNIX opera/ng system developed in 1969. DEC PDP- 8 The UNIX Opera5ng System Developed in 1969 at Bell Labs. UNIX has been con/nuously updated from 1969 to present. UNIX has been developed for all types of processors including Intel chips (Linux). UNIX was one of the first opera/ng systems for serious scien/fic compu/ng.
Computa5onal Chemistry in the 1960s and 70s Computers remained out of the mainstream of chemistry due to slow speeds and expense. S/ll, numbers of computa/onal chemistry ar/cles grew steadily. Microprocessor chip introduced by Intel in 1972. First supercomputer developed in 1976. Compu5ng in the 1970s Important developments:
The Development of the Supercomputer CRAY- 1 was developed in 1976. Cray- 1 had a speed of 100 Mflops. Today s quad- core processors have speeds of ~50 Gflops. 1980s - Introduc5on of the PC 1983 - IBM PC introduced. Not of use in computa/onal chemistry - - too slow. In 70s and 80s, approximately 30% of the computer /me on supercomputers was used by computa/onal chemists.
1990s to Present - Explosion of Computa5onal Chemistry Key Developments: graphics and visualiza/on affordable fast processors cheap memory and hard drives high- speed networking 1990s to Present - Explosion of Computa5onal Chemistry Introduc/on of less expensive UNIX- based worksta5ons brought affordable means of performing simula/ons. Development of widely available commercial so_ware packages brought compu/ng to the desktop for many chemists.
1990s to Present - Explosion of Computa5onal Chemistry John Pople - 1998 Nobel Prize for his work in computa/onal chemistry (shared with Walter Kohn). Gaussian so_ware package first developed by Pople s group in 1970, widely used by researchers for molecular calcula/ons. 1990s: State- of- the- art Calcula5ons Crambin (small plant protein) 642 atoms In 1998, 100 days of computer /me required for a quantum calcula/on of crambin (on a DEC Alpha worksta/on) good agreement with X- ray structure
Computa5onal Chemistry in the Present No end in sight to compu/ng increases. Speeds of Petaflops (1000 Tflops) have been reached (10 million )mes faster than 1st supercomputer). Current max > 30 Petaflops. Increased compu/ng power allows for more accurate simula/ons and larger systems. June 2015 - Top 5 Supercomputers System # Cores Speed Tianhe- 2 Nat. Supercomp. Ctr., China Titan Oak Ridge Nat. Lab, US Sequoia Lawrence Livermore Nat. Lab, US K computer RIKEN Adv. Inst., Japan Mira Argonne Nat. Lab, US 3,120,000 33.9 Pflops 560,000 17.6 Pflops 1,570,000 17.1 Pflops 700,000 10.5 Pflops 790,000 10.1 Pflops from hop://www.top500.org
History of Supercomputer Speeds from hop://www.top500.org Beyond Commercial Supercomputers: Compu5ng Clusters What is a compu/ng cluster? How and why are they being used in computa/onal chemistry? 192- core cluster at Texas Tech Univ.
What are Compu5ng Clusters? Compu/ng clusters consist of groups of cheap computers (PCs, small UNIX worksta/ons) connected by high- speed communica/ons so that they can run in parallel. A cluster may consist of individual PC towers hooked together 128- core cluster at Univ. of Calgary What are Compu5ng Clusters? Or the cluster may consist of individual CPUs added to a rack- type system. 768- core cluster at Univ. of Missouri
What are Compu5ng Clusters? They may be home built. 72- core cluster at RPI (home built) Or they may be purchased from commercial retailers. 128- core cluster at ISU (from Parallel Quantum Solu/ons) How and why are compu5ng clusters used in computa5onal chemistry? Clusters can be constructed or purchased for a frac/on of the cost of a commercial supercomputer. Their cost- effec/ve nature makes clusters ideal for individual research groups or departments. Chemistry Dept. cluster at Univ. of Wisconsin
How and why are compu5ng clusters used in computa5onal chemistry? The clusters may approach speeds of Tflops, and they easily produce 100s of Gflops. As a result, clusters may be used for modeling molecular systems of almost all types and sizes. 80- core cluster at Wabash College