Optimising Sparse Matrix Vector multiplication for large scale FEM problems on FPGA

Sparse Matrix Vector multiplication (SpMV) is an important kernel in many scientific applications. In this work we propose an architecture and an automated customisation method to detect and optimise the architecture for block diagonal sparse matrices. We evaluate the proposed approach in the context of the spectral/hp Finite Element Method, using the local matrix assembly approach. This problem leads to a large sparse system of linear equations with block diagonal matrix which is typically solved using an iterative method such as the Preconditioned Conjugate Gradient. The efficiency of the proposed architecture combined with the effectiveness of the proposed customisation method reduces BRAM resource utilisation by as much as 10 times, while achieving identical throughput with existing state of the art designs and requiring minimal development effort from the end user. In the context of the Finite Element Method, our approach enables the solution of larger problems than previously possible, enabling the applicability of FPGAs to more interesting HPC problems

An efficient sparse conjugate gradient solver using a Beneš permutation network

© 2014 Technical University of Munich (TUM).The conjugate gradient (CG) is one of the most widely used iterative methods for solving systems of linear equations. However, parallelizing CG for large sparse systems is difficult due to the inherent irregularity in memory access pattern. We propose a novel processor architecture for the sparse conjugate gradient method. The architecture consists of multiple processing elements and memory banks, and is able to compute efficiently both sparse matrix-vector multiplication, and other dense vector operations. A Beneš permutation network with an optimised control scheme is introduced to reduce memory bank conflicts without expensive logic. We describe a heuristics for offline scheduling, the effect of which is captured in a parametric model for estimating the performance of designs generated from our approach

CASK - Open-source custom architectures for sparse kernels

© 2016 ACM.Sparse matrix vector multiplication (SpMV) is an impor- tant kernel in many scientific applications. To improve the performance and applicability of FPGA based SpMV, we propose an approach for exploiting properties of the input matrix to generate optimised custom architectures. The ar- chitectures generated by our approach are between 3.8 to 48 times faster than the worst case architectures for each matrix, showing the benefits of instance specific design for SpMV

Run-time reconfigurable acceleration for genetic programming fitness evaluation in trading strategies

Genetic programming can be used to identify complex patterns in financial markets which may lead to more advanced trading strategies. However, the computationally intensive nature of genetic programming makes it difficult to apply to real world problems, particularly in real-time constrained scenarios. In this work we propose the use of Field Programmable Gate Array technology to accelerate the fitness evaluation step, one of the most computationally demanding operations in genetic programming. We propose to develop a fully-pipelined, mixed precision design using run-time reconfiguration to accelerate fitness evaluation. We show that run-time reconfiguration can reduce resource consumption by a factor of 2 compared to previous solutions on certain configurations. The proposed design is up to 22 times faster than an optimised, multithreaded software implementation while achieving comparable financial returns

Point prevalence of surgical checklist use in Europe: relationship with hospital mortality

Background The prevalence of use of the World Health Organization surgical checklist is unknown. The clinical effectiveness of this intervention in improving postoperative outcomes is debated. Methods We undertook a retrospective analysis of data describing surgical checklist use from a 7 day cohort study of surgical outcomes in 28 European nations (European Surgical Outcomes Study, EuSOS). The analysis included hospitals recruiting >10 patients and excluding outlier hospitals above the 95th centile for mortality. Multivariate logistic regression and three-level hierarchical generalized mixed models were constructed to explore the relationship between surgical checklist use and hospital mortality. Findings are presented as crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs). Results A total of 45 591 patients from 426 hospitals were included in the analysis. A surgical checklist was used in 67.5% patients, with marked variation across countries (0-99.6% of patients). Surgical checklist exposure was associated with lower crude hospital mortality (OR 0.84, CI 0.75-0.94; P=0.002). This effect remained after adjustment for baseline risk factors in a multivariate model (adjusted OR 0.81, CI 0.70-0.94; P<0.005) and strengthened after adjusting for variations within countries and hospitals in a three-level generalized mixed model (adjusted OR 0.71, CI 0.58-0.85; P<0.001). Conclusions The use of surgical checklists varies across European nations. Reported use of a checklist was associated with lower mortality. This observation may represent a protective effect of the surgical checklist itself, or alternatively, may be an indirect indicator of the quality of perioperative care. Clinical trial registration The European Surgical Outcomes Study is registered with ClinicalTrials.gov, number NCT0120360

Algorithm of diagnosis and treatment of thrombophilia in pregnancy – the experience of the obstetrics-gynecology department of the emergency university hospital Bucharest

University Emergency Hospital, Dept of Ob/Gyn, Bucharest, Romania, Al VI-lea Congres Național de Obstetrică și Ginecologie cu participare internațională, 13-15 septembrie 2018, Chișinău, Republica MoldovaThrombophilias defines a group of disorders associated with an increased tendency for thrombosis. They may also be seen as a heterogeneous group of conditions that have been associated during time with a variety of pregnancy complications, including early and late fetal loss, intrauterine fetal death, placental abruption, poor fetal growth (IUGR) and preeclampsia. Our clinical retrospective study was performed between 1st January 2006 and 30th June 2008. We evaluated 11518 pregnant women, who delivered in our Clinic, out of which 254 (2.20%) had different types of thrombophilias: antiphospholipid antibody syndrome (62.20%), factor V Leiden (16.93%), protein S deficiency (14.17%), protein C deficiency (3.94%), antithrombin III deficiency (2.76%). Preeclampsia was present at 27.17% of patients, out of which most cases were recorded in the APLS (36.08%), followed by APCR (30%) and the protein S deficiency (8.33%). There were mild forms of preeclampsia and they occurred in the patients who started treatment late (after the 26th week of pregnancy, due to the moment of diagnosis). Fetal pathology was represented by IUGR (20.47%) and premature birth (11.81%). The health condition of newborns, expressed by the Apgar index was very good in most of the cases (IA=10: 8.66%, IA=9: 71.26%, IA=8: 14.96%, IA=7: 3.94%, IA-6: 1.18%). The favorable evolution of the fetuses was due to the early diagnosis established and the proper treatment administrated. We had no fetal death in the group of diagnosed and treated thrombophilia patients, as well as no other thromboembolic complication. In a conclusion, we think that there are several important issues that should be taken into account when managing a pregnant thrombophilic woman. It is of great importance: • To think that pregnancy is a state of acquired hypercoagulability and that women hiding a thrombophilia may present with clinical symptoms for the first time during gestation or the puerperium – so think THROMBOPHILIA. � To correctly select the patients for thrombophilia testing. � To choose the correct moment for testing. � To provide thromboprophylaxis before the occurrence of any obstetrical complication mentioned above. � To judge correctly especially during the second half of pregnancy the ultrasonic appearance of the placenta, the growth curves of the fetus, and the placental circulation, elements that can modulate the management of that pregnancy (modifying the dosage of anticoagulant, establishing the right time for delivery)

Thermal transport in nanoelectronic devices cooled by on-chip magnetic refrigeration

On-chip demagnetization refrigeration has recently emerged as a powerful tool for reaching microkelvin electron temperatures in nanoscale structures. The relative importance of cooling on-chip and off-chip components and the thermal subsystem dynamics are yet to be analyzed. We study a Coulomb blockade thermometer with on-chip copper refrigerant both experimentally and numerically, showing that dynamics in this device are captured by a first-principles model. Our work shows how to simulate thermal dynamics in devices down to microkelvin temperatures, and outlines a recipe for a low-investment platform for quantum technologies and fundamental nanoscience in this novel temperature range.Comment: 11 pages, 10 figure

Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 $< p_{\rm{T}, assoc} < p_{\rm{T}, trig} <$ 5.0 GeV/$c$ is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range $|\eta|<0.9$. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161