# Presentation: 805465

## Taming Complexity:  

***Ames Laboratory***

**Taming Complexity:  **
**The Promise of High Performance Computing**

- BES Science 2018:
-  A Future Retrospective Symposium
- in the style of Iran Thomas

**Bruce Harmon**

## Complexity

**Almost Zen:**
**If you tame a complex problem,**
**it is no longer a complex problem. **

**“****I have yet to see any problem, however complicated, which when you looked at it in the right way, did not become still more complicated.”**
**                                         ****Poul Anderson**

##  Principle for (Successful) Predictions

**     “****Paris in the twentieth century - and, more specifically, in 1960 - teems with prodigies that were hard to imagine a hundred years before; yet Jules Verne imagined them because the science and technology of his day suggested their possibility.  Imagination is the capacity to rearrange available data or to extrapolate from them, and Verne was a masterful extrapolator.”**

**    ****From Eugen Weber’s introduction to “Paris in the **
**    ****Twentieth Century” written in 1863 by Jules Verne, **
**    ****but not found until 1989.**

## Slide 4

## Moore’s Law

- It cannot continue.  There will not be picotechnology.
- The question is “how far can we push?”
- Many rational arguments for pessimism.
- Optimism requires belief that difficult problems can be overcome...
- 2018 is off the road map, but clever people can do amazing things (not magic).

##                 Some Past Predictions:

- 1943
- "I think there is a world market for maybe five computers."
- --Thomas Watson, chairman of IBM
**1949**
- "Computers in the future may weigh no more than 1.5 tons.”
-  --Popular Mechanics, forecasting the relentless march of science
- 1977
- "There is no reason anyone would want a computer in their home."
- --Ken Olson, president, chairman and founder of Digital Equipment Corp.
**1981**
**“****640K ought to be enough for anybody”**
**- -    Bill Gates**

## Dramatic advances in theory and algorithms

**In Computational Materials Science the amplification from intellect (****new theory, algorithms, and insights****) is at least equal to the speed -up from hardware**** **

*Relative performance increase of Ising model simulations (■) compared the normalized speed of the computers (**●**) the simulations were executed on. The dashed line is a schematic of the increase in peak performance of the fastest supercomputers since 1972.*

- Moore’s law

- David Landau: UGA

## Many CMS application codes scale on parallel computers

**Compaq, PSC**

**4.58 Tflops!**

- x

**Similar data for other codes**
- Paratec
- FLAPW
**Gordon Bell Prizes**
- 1992 – KKR-CPA: Price Performance
- 1995 - TBMD: Fastest real application
- 1999 – LSMS: Fastest real application
**10****4**** improvement since 1988**
- GB Prize
**1988  -   1 Gflop/s**
**2001  - 11 Tflop/s**

## Dramatic Advances in Theory and Algorithms

**Allow treatment of complex systems and phenomena**
**A couple of examples / projections:**
**Light weight materials**
**Microstructure in Aluminum casting**
**Magnetic storage and recording**
**Nano-magnetism**

## Microstructure – Property Relationships

**Engine Block**
** ****1 meter**

**Microstructure **
**- Grains**
** ****1 – 10 mm**
**Properties**
- • High cycle fatigue
- • Ductility

- Chris Wolverton Ford Motor Company

**Atoms**
** ****10-100 Angstroms**
**Properties**
- • Thermal Growth

## Storage Density Trends

**Storage Density Trends**

**Density, Mbits/in****2**

**Year**

**1990**

**2000**

**2010**

**100,000**

**10,000**

**  ****1,000**

**  ****100**

**  ****10**

***NSF-MRSEC***

*05/22/03   ISU*

***KECK***

***CMRA***

## Magnetic Nanostructures

- IBM disk drive with GB capacity

- GMR Read Head

**Technology demands treatment of complex phenomena**
**GMR read head takes advantage of advances in **_**basic science**_
- Oscillatory exchange coupling
- Giant Magneto-Resistance
- Exchange Bias

## Nanoscience –  Complexity demands Modeling

-  **Synthesis & Characterization                     Theory & Simulation**
-  **Nano wires and particles**
** ****Magnetic structure of matrix and surface nanostructures**
** ****Dynamics & switching**
** ****Spin transport**

- Magnetic nanostructures
**Effects of Dimensional Confinement on Spin Structure, Dynamics and Transport**** **
**Spintronics**
- First principles simulation size             Real system size

- Fe

**~ ****12,000 atoms**
**~   2,000 surface atoms **

## 2018: Nanomagnetism

- Effects of Dimensional Confinement of Spin Structure, Dynamics and Transport
**Nanowires and particles**
**Confinement modifies**
**Spin structure, **
**Dynamics,  **
**Transport**
**Decoherence and QC**
- New concepts
**Active control of spin**

*2018: Nanomagnetism*

**Quantum**** ****Corral: Eigler (IBM)**** **

**New Quantum Phenomena **

**Magnetic Molecules as Building Blocks**

** ****Fe****30**

## An Emerging Transformation in the Structure of Computational Materials Science

**Historical structure of theory and computation in condensed matter physics**
**Many complex problems**
**No over arching “problem”**
**Rapidly changing focus**
**Rapidly developing techniques**
**Codes/Methods developed by small groups - students**
**“****Cottage Industry” – Bill McCurdy**
**Sophisticated models and codes exist at every length scale.**
**These codes come out of *****different cottages***** and are hard to integrate.**
**Developed for incompatible architectures.**
**Fast pace of development does not allow for rewriting codes from**** ****scratch****.**

- Quantum

- Spin Models

- Micromagnetics

- Micromagnetics

**Large FORTRAN codes (>20,000 lines) developed over a long time period (>20 years)**

**Monolithic C or FORTRAN codes usually designed to solve a particular problem**

**Codes designed to run on PCs with emphasis on graphical user interface**

***Ultrascale Computation demands a ******new approach***

## New Approach: NanoScience

- Joint BESAC-ASCAC NanoScience workshop – May 2002
- Fully developing the potential of the DOE-OS Nano-centers will require a new level of _integration of experiment, theory and simulation._
- Advanced theory and simulation require _multidisciplinary teams_
- Materials Scientists
- Applied Mathematicians
- Computer Scientists

## New Approach: Facilities  analogy

**Spallation Neutron Source (SNS) ****Center for Nanophase Materials Science (CNMS)****   **

**NERSC **
**3,328-processor **
**5 teraflop/s**

- Fe

- Facility

**User ****Community**

- Instrumentation** **

## Reminder!

**Reminder!**
**“****In the technology world, **_**software**_**, not hardware, determines the state of the art and the pace of change.”**
**- David Gelernter, **
**Yale professor of CS**
**and entrepreneur.**

## Computational Materials Science Network

**Advance frontiers in computational materials science by assembling diverse sets of researchers committed to working together in order to solve outstanding materials problems that require cooperation across organizational and disciplinary boundaries.**

**Theory vs. Experiment:**
**silicon nanoclusters**

- Excited State Electronic Structure CRT

***Computational Materials Science Network***

## New Approach: Collaborative Research Teams (CRT)

* ****Assembles interdisciplinary experts to solve complex problems***
*** ******Requires high-performance computation facilities***
*** ******Develops new computational tools, algorithms***

***New Approach: Collaborative Research Teams (CRT)***

## Achievements by 2018

_**Algorithms**_** developed and routinely applied for:**
**Correlated electron systems**
**Integrated photonic/electronic nanostuctures**
**Electronic and spin transport in complex molecules**
_**Simulations**_** on classical computers are indispensable for the design of prototype scalable quantum computers.**
**Computer Designed **_**materials**_** synthesized by plants and animals (in Iowa).  **
**Length and time scales will be bridged - Ford engine.**

## 2018 - continued

**Simulations are able to follow the gene expression and development from a single cell to a full grown ____________.  Design bacteria for environmental cleanup.**
**Nobel prize for high Tc superconductivity.**
**Composite nano materials, fabricated by computer control of the synthesis, with computationally optimized physical characteristics. **
**The number of Computational Materials Scientists employed by industry will increase by a factor of ten.**

## and to Iran Thomas for is initial support and continuing  

**	**
**	****Malcolm Stock, Oak Ridge National Laboratory**
**	****Ellen Stechel, Ford Motor Company**
**and to ****Iran Thomas**** for is initial support and continuing  **
**enthusiasm for the Computational Materials Sciences **
**Network.**

##  Earth Simulator - A wakeup call?

- Why the fuss and feathers?
- Usable flops vs theoretical performance!
- Many commodity chips vs Fewer vector
- Example: Climate modeling
- Codes ~8% efficient (overall ES x80-x100)
- But: Materials
- Codes ~40-75% efficient on IBM SP3/4