| 1. |
- Lozano, Rafael, et al.
(författare)
-
Measuring progress from 1990 to 2017 and projecting attainment to 2030 of the health-related Sustainable Development Goals for 195 countries and territories: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - : Elsevier. - 1474-547X .- 0140-6736. ; 392:10159, s. 2091-2138
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Efforts to establish the 2015 baseline and monitor early implementation of the UN Sustainable Development Goals (SDGs) highlight both great potential for and threats to improving health by 2030. To fully deliver on the SDG aim of “leaving no one behind”, it is increasingly important to examine the health-related SDGs beyond national-level estimates. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017), we measured progress on 41 of 52 health-related SDG indicators and estimated the health-related SDG index for 195 countries and territories for the period 1990–2017, projected indicators to 2030, and analysed global attainment. Methods: We measured progress on 41 health-related SDG indicators from 1990 to 2017, an increase of four indicators since GBD 2016 (new indicators were health worker density, sexual violence by non-intimate partners, population census status, and prevalence of physical and sexual violence [reported separately]). We also improved the measurement of several previously reported indicators. We constructed national-level estimates and, for a subset of health-related SDGs, examined indicator-level differences by sex and Socio-demographic Index (SDI) quintile. We also did subnational assessments of performance for selected countries. To construct the health-related SDG index, we transformed the value for each indicator on a scale of 0–100, with 0 as the 2·5th percentile and 100 as the 97·5th percentile of 1000 draws calculated from 1990 to 2030, and took the geometric mean of the scaled indicators by target. To generate projections through 2030, we used a forecasting framework that drew estimates from the broader GBD study and used weighted averages of indicator-specific and country-specific annualised rates of change from 1990 to 2017 to inform future estimates. We assessed attainment of indicators with defined targets in two ways: first, using mean values projected for 2030, and then using the probability of attainment in 2030 calculated from 1000 draws. We also did a global attainment analysis of the feasibility of attaining SDG targets on the basis of past trends. Using 2015 global averages of indicators with defined SDG targets, we calculated the global annualised rates of change required from 2015 to 2030 to meet these targets, and then identified in what percentiles the required global annualised rates of change fell in the distribution of country-level rates of change from 1990 to 2015. We took the mean of these global percentile values across indicators and applied the past rate of change at this mean global percentile to all health-related SDG indicators, irrespective of target definition, to estimate the equivalent 2030 global average value and percentage change from 2015 to 2030 for each indicator. Findings: The global median health-related SDG index in 2017 was 59·4 (IQR 35·4–67·3), ranging from a low of 11·6 (95% uncertainty interval 9·6–14·0) to a high of 84·9 (83·1–86·7). SDG index values in countries assessed at the subnational level varied substantially, particularly in China and India, although scores in Japan and the UK were more homogeneous. Indicators also varied by SDI quintile and sex, with males having worse outcomes than females for non-communicable disease (NCD) mortality, alcohol use, and smoking, among others. Most countries were projected to have a higher health-related SDG index in 2030 than in 2017, while country-level probabilities of attainment by 2030 varied widely by indicator. Under-5 mortality, neonatal mortality, maternal mortality ratio, and malaria indicators had the most countries with at least 95% probability of target attainment. Other indicators, including NCD mortality and suicide mortality, had no countries projected to meet corresponding SDG targets on the basis of projected mean values for 2030 but showed some probability of attainment by 2030. For some indicators, including child malnutrition, several infectious diseases, and most violence measures, the annualised rates of change required to meet SDG targets far exceeded the pace of progress achieved by any country in the recent past. We found that applying the mean global annualised rate of change to indicators without defined targets would equate to about 19% and 22% reductions in global smoking and alcohol consumption, respectively; a 47% decline in adolescent birth rates; and a more than 85% increase in health worker density per 1000 population by 2030. Interpretation: The GBD study offers a unique, robust platform for monitoring the health-related SDGs across demographic and geographic dimensions. Our findings underscore the importance of increased collection and analysis of disaggregated data and highlight where more deliberate design or targeting of interventions could accelerate progress in attaining the SDGs. Current projections show that many health-related SDG indicators, NCDs, NCD-related risks, and violence-related indicators will require a concerted shift away from what might have driven past gains—curative interventions in the case of NCDs—towards multisectoral, prevention-oriented policy action and investments to achieve SDG aims. Notably, several targets, if they are to be met by 2030, demand a pace of progress that no country has achieved in the recent past. The future is fundamentally uncertain, and no model can fully predict what breakthroughs or events might alter the course of the SDGs. What is clear is that our actions—or inaction—today will ultimately dictate how close the world, collectively, can get to leaving no one behind by 2030.
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| 2. |
- Murray, Christopher J. L., et al.
(författare)
-
Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
-
Ingår i: The Lancet. - 1474-547X .- 0140-6736. ; 392:10159, s. 1995-2051
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Tidskriftsartikel (refereegranskat)abstract
- Background: Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods: We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10–54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10–14 years and 50–54 years was estimated from data on fertility in women aged 15–19 years and 45–49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories. Findings: From 1950 to 2017, TFRs decreased by 49·4% (95% uncertainty interval [UI] 46·4–52·0). The TFR decreased from 4·7 livebirths (4·5–4·9) to 2·4 livebirths (2·2–2·5), and the ASFR of mothers aged 10–19 years decreased from 37 livebirths (34–40) to 22 livebirths (19–24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83·8 million people per year since 1985. The global population increased by 197·2% (193·3–200·8) since 1950, from 2·6 billion (2·5–2·6) to 7·6 billion (7·4–7·9) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2·0%; this rate then remained nearly constant until 1970 and then decreased to 1·1% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2·5% in 1963 to 0·7% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2·7%. The global average age increased from 26·6 years in 1950 to 32·1 years in 2017, and the proportion of the population that is of working age (age 15–64 years) increased from 59·9% to 65·3%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1·0 livebirths (95% UI 0·9–1·2) in Cyprus to a high of 7·1 livebirths (6·8–7·4) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0·08 livebirths (0·07–0·09) in South Korea to 2·4 livebirths (2·2–2·6) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0·3 livebirths (0·3–0·4) in Puerto Rico to a high of 3·1 livebirths (3·0–3·2) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2·0% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger. Interpretation: Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress. Funding: Bill & Melinda Gates Foundation.
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| 3. |
- Harris, Tim, et al.
(författare)
-
Matrix Multiplication on the Connection Machine
- 1989
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Konferensbidrag (refereegranskat)abstract
- A data parallel implementation of the multiplication of matrices of arbitrary shapes and sizes is presented. A systolic algorithm based on a rectangular processor layout is used by the implementation. All processors contain submatrices of the same size for a given operand. Matrix-vector multiplication is used as a primitive for local matrix-matrix multiplication in the Connection Machine system CM-2 implementation. The peak performance of the local matrix-matrix multiplication is in excess of 20 Gflops s-1. The overall algorithm including all required data motion has a peak performance of 5.8 Gflops s-1.
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| 4. |
- Johan, Zdenek, et al.
(författare)
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A Data Parallel Finite Element Method for Computational Fluid Dynamics on the Connection Machine Systems
- 1992
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Ingår i: Computer Methods in Applied Mechanics and Engineering. - : Elsevier BV. - 0045-7825 .- 1879-2138. ; 99:1, s. 113-134
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Tidskriftsartikel (refereegranskat)abstract
- A finite element method for computational fluid dynamics has been implemented on the Connection Machine systems CM-2 and CM-200. An implicit iterative solution strategy, based on the pre-conditioned matrix-free GMRES algorithm, is employed. Parallel data structures built on both nodal and elemental sets are used to achieve maximum parallelization. Communication primitives provided through the Connection Machine Scientific Software Library substantially improved the overall performance of the program. Computations of three-dimensional compressible flows using unstructured meshes having close to one million elements, such as a complete airplane, demonstrate that the Connection Machine systems are suitable for these applications. Performance comparisons are also carried out with the vector computers Cray Y-MP and Convex C-1.
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| 5. |
- Johan, Zdenek, et al.
(författare)
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An Efficient Communication Strategy for Finite Element Methods on the Connection Machine CM-5 System
- 1994
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Ingår i: Computer Methods in Applied Mechanics and Engineering. - 0045-7825 .- 1879-2138. ; 113:3-4, s. 363-387
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this paper is to propose communication procedures suitable for unstructured finite element solvers implemented on distributed-memory parallel computers such as the Connection Machine CM-5 system. First, a data-parallel implementation of the recursive spectral bisection (RSB) algorithm proposed by Pothen et al. is presented. The RSB algorithm is associated with a node renumbering scheme which improves data locality of reference. Two-step gather and scatter operations taking advantage of this data locality are then designed. These communication primitives make use of the indirect addressing capability of the CM-5 vector units to achieve high gather and scatter bandwidths. The performance of the proposed communication strategy is illustrated on large-scale three-dimensional fluid dynamics problems
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| 6. |
- Johnsson, Lennart, et al.
(författare)
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Data Structures and Algorithms for the Finite Element Method on a Data Parallel Supercomputer
- 1990
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Ingår i: International Journal for Numerical Methods in Engineering. - : Wiley. - 0029-5981 .- 1097-0207. ; 29:4, s. 881-908
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Tidskriftsartikel (refereegranskat)abstract
- This article describes a formulation of the finite element method and its implementation on a data parallel computing system. The Connection Machine® system, CM-2, has been used as the model architecture. Data structures, storage requirements, communication and parallel arithmetic complexity are analysed in detail for the cases when a processor represents an unassembled finite element and when a processor is assigned to an unassembled nodal point. Data parallel algorithms for the grid generation, the evaluation of the elemental stiffness matrices and for the iterative solution of the linear system are presented. The algorithm for evaluating the elemental stiffness matrices computes the matrix elements concurrently without communication. This concurrency is in addition to the inherent parallelism present among different finite elements. A conjugate gradient solver with diagonal pre-conditioner is used for the solution of the resulting linear system. Results from an implementation of the three-dimensional finite element method based on Lagrange elements are reported. For single-precision floating-point operations, the measured peak performance is approximately 2·4 G flops s−1 for evaluating the elemental stiffness matrices and approximately 850 M flops s−1 for the conjugate gradient solver. On a Connection Machine system with 16K physical processors, the time per conjugate gradient iteration for an application with 400 000 degrees of freedom is approximately 0·13 s for double-precision floating-point operations.
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| 7. |
- Johnsson, Lennart, et al.
(författare)
-
Experience with the Conjugate Gradient Method for Stress Analysis on a Data Parallel Supercomputer
- 1989
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Ingår i: International Journal for Numerical Methods in Engineering. - : Wiley. - 0029-5981 .- 1097-0207. ; 27:3, s. 523-546
-
Tidskriftsartikel (refereegranskat)abstract
- The storage requirements and performance consequences of a few different data parallel implementations of the finite element method for domains discretized by three-dimensional brick elements are reviewed. Letting a processor represent a nodal point per unassembled finite element yields a concurrency that may be one to two orders of magnitude higher for common elements than if a processor represents an unassembled finite element. The former representation also allows for higher order elements with a limited amount of storage per processor. A totally parallel stiffness matrix generation algorithm is presented. The equilibrium equations are solved by a conjugate gradient method with diagonal scaling. The results from several simulations designed to show the dependence of the number of iterations to convergence upon the Poisson ratio, the finite element discretization and the element order are reported. The domain was discretized by three-dimensional Lagrange elements in all cases. The number of iterations to convergence increases with the Poisson ratio. Increasing the number of elements in one special dimension increases the number of iterations to convergence, linearly. Increasing the element order p in one spatial dimension increases the number of iterations to convergence as pα, where α is 1·4–1·5 for the model problems.
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| 8. |
- Johnsson, Lennart, et al.
(författare)
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High Performance, Scalable Scientific Software Libraries
- 1994
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Ingår i: <em>Portability and Performance in Parallel Processing</em>. - : John Wiley & Sons. ; , s. 159-208
-
Bokkapitel (refereegranskat)abstract
- Massively parallel processors introduces new demands on software systems with respect to performance, scalability, robustness and portability. The increased complexity of the memory systems and the increased range of problem sizes for which a given piece of software is used, poses serious challenges to software developers. The Connection Machine Scientific Software Library, CMSSL, uses several novel techniques to meet these challenges. The CMSSL contains routines for managing the data distribution and provides data distribution independent functionality. High performance is achieved through careful scheduling of operations and data motion, and through the automatic selection of algorithms at run--time. We discuss some of the techniques used, and provide evidence that CMSSL has reached the goals of performance and scalability for an important set of applications.
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| 9. |
- Johnsson, Lennart, et al.
(författare)
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Massively Parallel Computing: Mathematics and Communications Libraries
- 1993
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Ingår i: <em>Parallel Supercomputing in Atmospheric Science</em>. - : World Scientific. ; , s. 250-285
-
Bokkapitel (refereegranskat)abstract
- Massively parallel computing holds the promise of extreme performance. The utility of these systems will depend heavily upon the availability of libraries until compilation and run-- time system technology is developed to a level comparable to what today is common on most uniprocessor systems. Critical for performance is the ability to exploit locality of reference and effective management of the communication resources. We discuss some techniques for preserving locality of reference in distributed memory architectures. In particular, we discuss the benefits of multidimensional address spaces instead of the conventional linearized address spaces, partitioning of irregular grids, and placement of partitions among nodes. Some of these techniques are supported as language directives, others as run--time system functions, and others still are part of the Connection Machine Scientific Software Library, CMSSL. We briefly discuss some of the unique design issues in this library for distribute...
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| 10. |
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| 11. |
- Johnsson, Lennart, et al.
(författare)
-
Scientific Software Libraries for Scalable Architectures
- 1994
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Ingår i: <em>Parallel Scientific Computing</em>. - : Springer-Verlag New York.
-
Bokkapitel (refereegranskat)abstract
- Massively parallel processors introduce new demands on software systems with respect to performance, scalability, robustness and portability. The increased complexity of the memory systems and the increased range of problem sizes for which a given piece of software is used, poses serious challenges to software developers. The Connection Machine Scientific Software Library, CMSSL, uses several novel techniques to meet these challenges. The CMSSL contains routines for managing the data distribution and provides data distribution independent functionality. High performance is achieved through careful scheduling of arithmetic operations and data motion, and through the automatic selection of algorithms at run--time. We discuss some of the techniques used, and provide evidence that CMSSL has reached the goals of performance and scalability for an important set of applications. 1 Introduction The main reason for large scale parallelism is performance. In order for massively parallel archit...
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| 12. |
- Mathur, Kapil K, et al.
(författare)
-
All–to–all Communication Algorithms for Distributed BLAS
- 1993
-
Konferensbidrag (refereegranskat)abstract
- based on all--to--all broadcast and all--to--all reduce are presented. For DBLAS, at each all--to--all step, it is necessary to know the data values and the indices of the data values as well. This is in contrast to the more traditional applications of all--to--all broadcast (such as a N--body solver) where the identity of the data values is not of much interest. Detailed schedules for all--to--all broadcast and reduction are given for the data motion of arrays mapped to the processing nodes of binary cube networks using binary encoding and binary--reflected Gray encoding. The algorithms compute the indices for the communicated data locally. No communication bandwidth is consumed for data array indices. For the Connection Machine system CM--200, Hamiltonian cycle based all--to--all communication algorithms improve the performance by a factor of two to ten over a combination of tree, butterfly network, and router based algorithms. The data rate achieved for all--to--all broadcast on a 256 node Connection Machine system CM--200 is 0.3 Gbytes/sec. The data motion rate for all--to--all broadcast, including the time for index computations and local data reordering, is about 2.8 Gbytes/sec for a 2048 node system. Excluding the time for index computation and local memory reordering the measured data motion rate for all--to--all broadcast is 5.6 Gbytes/s. On a Connection Machine system, CM--200, with 2048 processing nodes, the overall performance of the distributed matrix vector multiply (DGEMV) and vector matrix multiply (DGEMV with TRANS) is 10.5 Gflops/s and 13.7 Gflops/s respectively.
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| 13. |
- Mathur, Kapil K., et al.
(författare)
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Communication Primitives for Unstructured Finite Element Simulations on Data Parallel Architectures
- 1992
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Ingår i: Computing systems in engineering. ; 3:1-4, s. 63-72
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Tidskriftsartikel (refereegranskat)abstract
- Efficient data motion is critical for high performance computing on distributed memory architectures. The value of some techniques for efficient data motion is illustrated by identifying generic communication primitives. Further, the efficiency of these primitives is demonstrated on three different applications using the finite element method for unstructured grids and sparse solvers with different communication requirements. For the applications presented, the techniques advocated reduced the communication times by a factor of between 1.5 and 3.
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| 14. |
- Mathur, Kapil K, et al.
(författare)
-
Data Parallel Algorithms for the Finite Element Method
- 1990
-
Konferensbidrag (refereegranskat)abstract
- A data paralell implementation of the finite element method is described. The focus of the presentation is on data mapping and data motion. The essential ideas of the dataparallel implementation are developed for discretizations of regular domains by Lagrange elements ofarbitrary order in two and three dimensions, A generalization to irregular domains is also presented.Implementations of the data mappings for both regular and irregular domains have been made onthe Connection Machine®system model CM-2. Peak performances Well in excess of 2 Gñops have bee measured for the evaluation of the elemental stiffness matrices. The performance of the iterative solver is in the range of 600 850 Mñops s'1.
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| 15. |
- Mathur, Kapil K, et al.
(författare)
-
Element Order and Convergence Rate of the Conjugate Gradient Method for Stress Analysis on the Connection Machine
- 1989
-
Konferensbidrag (refereegranskat)abstract
- A data parallel formulation of the finite element method is described. The data structures and the algorithms for stiffness matrix generation and the solution of the equilibrium equations are presented briefly. The generation of the elemental stiffness matrices requires no communication, even though each finite element is distributed over several processors. The conjugate gradient method with a diagonal preconditioner has been used for the solution of the resulting sparse linear system. This formulation has been implemented on the Connection Machine® model CM-2. The simulations reported in this article investigate the influence of the mesh discretization and the interpolation order on the convergence behavior of the conjugate gradient method. A linear dependence of the convergence behavior on the mesh discretization parameter is observed. In addition, the convergence rate depends on the interpolation order p as (p1.6). The peak floating point rate (single-precision) for the evaluation of the stiffness matrix is approximately 2.4 Gflops s-1. The iterative solver peaks at nearly 850 Mflops s-1.
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| 16. |
- Mathur, Kapil K, et al.
(författare)
-
Multiplication of Matrices of Arbitrary Shape on a Data Parallel Computer
- 1994
-
Ingår i: Parallel Computing. - : Elsevier BV. - 0167-8191 .- 1872-7336. ; 20:7, s. 919-951
-
Tidskriftsartikel (refereegranskat)abstract
- Some level-2 and level-3 Distributed Basic Linear Algebra Subroutines (DBLAS) that have been implemented on the Connection Machine system CM-200 are described. No assumption is made on the shape or size of the operands. For matrix-matrix multiplication, both the nonsystolic and the systolic algorithms are outlined. A systolic algorithm that computes the product matrix in-place is described in detail. We show that a level-3 DBLAS yields better performance than a level-2 DBLAS. On the Connection Machine system CM-200, blocking yields a performance improvement by a factor of up to three over level-2 DBLAS. For certain matrix shapes the systolic algorithms offer both improved performance and significantly reduced temporary storage requirements compared to the nonsystolic block algorithms. We show that, in order to minimize the communication time, an algorithm that leaves the largest operand matrix stationary should be chosen for matrix-matrix multiplication. Furthermore, it is shown both analytically and experimentally that the optimum shape of the processor array yields square stationary submatrices in each processor, i.e. the ratio between the length of the axes of the processing array must be the same as the ratio between the corresponding axes of the stationary matrix. The optimum processor array shape may yield a factor of five performance enhancement for the multiplication of square matrices. For rectangular matrices a factor of 30 improvement was observed for an optimum processor array shape compared to a poorly chosen processor array shape.
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| 17. |
- Mathur, Kapil K, et al.
(författare)
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The Finite Element Method on a Data Parallel Architecture
- 1989
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Ingår i: International journal of high speed computing. - 0129-0533. ; 1:1, s. 29-44
-
Konferensbidrag (refereegranskat)abstract
- A data parallel implementation of the finite element method on the Connection Machine system CM-2® is presented. This implementation assumes that the elementary unit of data is an unassembled nodal point. In the context of the CM-2, each virtual processor represents an unassembled nodal point and nodal points shared between elements are replicated on different virtual processors. An algorithm for computing each elemental stiffness matrix concurrently, as well as different elemental stiffness matrices concurrently, without inter-processor communication is presented. The performance of the elemental stiffness matrix computation is in the range 1.6–1.9 GFlops s−1. The sparse system of linear equations that results from the finite element discretization has been solved by a conjugate gradient method with a diagonal preconditioner. The rate of convergence of the conjugate gradient iterations for boundary conditions which correspond to uniaxial deformations depends nonlinearly on the order of interpolation of the elements and linearly on the mesh discretization. Sample code segments are provided to illustrate the programming environment on a data parallel architecture.
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| 18. |
- Zdenek, Johan, et al.
(författare)
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Data Parallel Finite Element Techniques for Computational Fluid Dynamics on the Connection Machine Systems
- 1993
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Ingår i: <em>Parallel Computational Fluid Dynamics </em>. - : North Holland. ; , s. 215-229
-
Bokkapitel (refereegranskat)abstract
- A finite element method for computational fluid dynamics has been implemented on the Connection Machine systems CM-2 and CM-200. An implicit iterative solution strategy, based on the preconditioned matrix-free GMRES algorithm, is employed. Parallel data structures built on both nodal and elemental sets are used to achieve maximum parallelization. Communication primitives provided through the Connection Machine Scientific Software Library substantially improved the overall performance of the program. Computations of three-dimensional compressible flows using unstructured meshes having close to one million elements, such as a complete airplane, demonstrate that the Connection Machine systems are suitable for these applications. Performance comparisons are also carried out with the vector computers Cray Y-MP and Convex C-1. ii Contents Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2. T...
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| 19. |
- Zdenek, Johan, et al.
(författare)
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Mesh Decomposition and Communication Procedures for Finite Element Applications on the Connection Machine CM–5 System
- 1994. - 2
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Ingår i: <em>High–Performance Computing and Networking</em>. - : Springer-Verlag New York. ; , s. 233-240
-
Bokkapitel (refereegranskat)abstract
- The objective of this paper is to analyze the impact of data mapping strategies on the performance of finite element applications. First, we describe a parallel mesh decomposition algorithm based on recursive spectral bisection used to partition the mesh into element blocks. A simple heuristic algorithm then renumbers the mesh nodes. Large three-dimensional meshes demonstrate the efficiency of those mapping strategies and assess the performance of a finite element program for fluid dynamics.
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