{"546581":{"#nid":"546581","#data":{"type":"event","title":"Phd Defense by Phanisri Pradeep Pratapa","body":[{"value":"\u003Cp align=\u0022center\u0022\u003E\u003Cstrong\u003ESchool of Civil and Environmental Engineering\u003C\/strong\u003E\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003Cstrong\u003EPh.D. Thesis Defense Announcement\u003C\/strong\u003E\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003ETowards electronic structure calculations at the Exascale\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003Cstrong\u003EBy\u003C\/strong\u003E\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003EPhanisri Pradeep Pratapa\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003Cstrong\u003EAdvisor:\u003C\/strong\u003E\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003EDr. Phanish Suryanarayana (CEE)\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003Cstrong\u003ECommittee Members:\u003C\/strong\u003E\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003EDr. Glaucio H. Paulino (CEE), Dr. Arash Yavari (CEE),\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003EDr. Edmond Chow (CSE), Dr. John E. Pask (Lawrence Livermore National Laboratory)\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003Cstrong\u003EDate \u0026amp; Time:\u003C\/strong\u003E Thursday, July 7, 2016, at 2.00 PM\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003Cstrong\u003ELocation:\u003C\/strong\u003E Sustainable Education Building, 122\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003EDevelopment of new materials need better understanding of the behavior of materials at nanoscale which involves accurate simulation of\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003Eatomic and electronic interactions. Electronic structure is especially important when the atomic interactions involve breaking or formation of\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003Echemical bonds. When such interactions are present, first principles based ab-initio electronic structure calculations of atoms, which do not\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003Einvolve any empirical potentials, would be a suitable choice to study the behavior of materials at nanoscale. Such simulations involving many\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003Ethousands of atoms are intractable by current software (especially for metals) due to their cubic scaling with respect to the system size. In this\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003Edissertation, the cubic scaling bottleneck is overcome by developing a linear scaling method amenable to massive parallelization.\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003EA linear scaling Density Functional Theory (DFT) framework has been developed using Clenshaw-Curtis Spectral Quadrature (SQ) method\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003Eand implemented on massively parallel computers to simulate the electronic structure of hundreds of thousands of atoms. Finite difference\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003Erepresentation has been employed in order to exploit the locality of electronic interactions in real space, enable systematic convergence and\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003Efacilitate large-scale parallel implementation. In combination with linear scaling electrostatics, the electron density, energy and atomic forces\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003Ecan be calculated with effort that scales linearly with the number of atoms for both insulating and metallic systems.\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003EThe method is validated and systematic convergence of energy and forces to the exact diagonalization result is demonstrated. The efficiency\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003Eand suitability of the method for high temperature calculations is also discussed. The parallel scaling of the method to more than hundred\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003Ethousand processors involving many thousands of atoms has been studied. The extreme parallelizability demonstrated by the method\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003Epromises the potential to make use of the next generation exascale computer architectures for scientific simulations. In the spirit of massive\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003Eparallelizability and efficiency, new extrapolation techniques have been developed to accelerate the convergence of fixed point iterations.\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003EThese techniques when applied to basic iterative methods give rise to efficient solvers for linear systems of equations. Robust and efficient\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp align=\u0022LEFT\u0022\u003Eperformance of these methods is demonstrated in acceleration of the non-linear fixed point iteration that is used to solve the electronic\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp\u003Estructure problem.\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003C\/p\u003E\u003Cp\u003E \u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":"","field_summary_sentence":[{"value":"Towards electronic structure calculations at the Exascale"}],"uid":"27707","created_gmt":"2016-06-21 15:45:36","changed_gmt":"2016-10-08 02:18:07","author":"Tatianna Richardson","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2016-07-07T15:00:00-04:00","event_time_end":"2016-07-07T17:00:00-04:00","event_time_end_last":"2016-07-07T17:00:00-04:00","gmt_time_start":"2016-07-07 19:00:00","gmt_time_end":"2016-07-07 21:00:00","gmt_time_end_last":"2016-07-07 21:00:00","rrule":null,"timezone":"America\/New_York"},"extras":[],"groups":[{"id":"221981","name":"Graduate Studies"}],"categories":[],"keywords":[{"id":"100811","name":"Phd Defense"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78771","name":"Public"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}