Domain-Specific Acceleration and Auto-Parallelization of Legacy Scientific Code in FORTRAN 77 using Source-to-Source Compilation

Massively parallel accelerators such as GPGPUs, manycores and FPGAs represent a powerful and affordable tool for scientists who look to speed up simulations of complex systems. However, porting code to such devices requires a detailed understanding of heterogeneous programming tools and effective strategies for parallelization. In this paper we present a source to source compilation approach with whole-program analysis to automatically transform single-threaded FORTRAN 77 legacy code into OpenCL-accelerated programs with parallelized kernels. The main contributions of our work are: (1) whole-source refactoring to allow any subroutine in the code to be offloaded to an accelerator. (2) Minimization of the data transfer between the host and the accelerator by eliminating redundant transfers. (3) Pragmatic auto-parallelization of the code to be offloaded to the accelerator by identification of parallelizable maps and reductions. We have validated the code transformation performance of the compiler on the NIST FORTRAN 78 test suite and several real-world codes: the Large Eddy Simulator for Urban Flows, a high-resolution turbulent flow model; the shallow water component of the ocean model Gmodel; the Linear Baroclinic Model, an atmospheric climate model and Flexpart-WRF, a particle dispersion simulator. The automatic parallelization component has been tested on as 2-D Shallow Water model (2DSW) and on the Large Eddy Simulator for Urban Flows (UFLES) and produces a complete OpenCL-enabled code base. The fully OpenCL-accelerated versions of the 2DSW and the UFLES are resp. 9x and 20x faster on GPU than the original code on CPU, in both cases this is the same performance as manually ported code.Comment: 12 pages, 5 figures, submitted to "Computers and Fluids" as full paper from ParCFD conference entr

Re-estimation of argon isotope ratios leading to a revised estimate of the Boltzmann constant

In 2013, NPL, SUERC and Cranfield University published an estimate for the Boltzmann constant [1] based on a measurement of the limiting low-pressure speed of sound in argon gas. Subsequently, an extensive investigation by Yang et al [2] revealed that there was likely to have been an error in the estimate of the molar mass of the argon used in the experiment. Responding to [2], de Podesta et al revised their estimate of the molar mass [3]. The shift in the estimated molar mass, and of the estimate of kB, was large: -2.7 parts in 106, nearly four times the original uncertainty estimate. The work described here was undertaken to understand the cause of this shift and our conclusion is that the original samples were probably contaminated with argon from atmospheric air.
 In this work we have repeated the measurement reported in [1] on the same gas sample that was examined in [2, 3]. However in this work we have used a different technique for sampling the gas that has allowed us to eliminate the possibility of contamination of the argon samples. We have repeated the sampling procedure three times, and examined samples on two mass spectrometers. This procedure confirms the isotopic ratio estimates of Yang et al [2] but with lower uncertainty, particularly in the relative abundance ratio R38:36.
 Our new estimate of the molar mass of the argon used in Isotherm 5 in [1] is 39.947 727(15) g mol-1 which differs by +0.50 parts in 106 from the estimate 39.947 707(28) g mol-1 made in [3]. This new estimate of the molar mass leads to a revised estimate of the Boltzmann constant of kB = 1.380 648 60 (97) × 10−23 J K−1 which differs from the 2014 CODATA value by +0.05 parts in 106.&#13

Physics of the Quark-Gluon Plasma

Central nuclear collisions at energies far above 1 GeV/nucleon may provide for conditions, where the transition from highly excited hadronic matter into quark matter or quark-gluon plasma can be probed. Here I review our current understanding of the physical properties of a quark-gluon plasma and review ideas about the nature of, and signals for, the deconfinement transition. I also give a detailed presentation of recent progress in the treatment of the formation of a thermalized state at the parton level.Comment: 47 pages, 29 figures as separate uuencoded tar files, (format correction), DUKE-TH-92-3

A revised edition of the readiness to change questionnaire (treatment version)

The UK Alcohol Treatment Trial provided an opportunity to examine the factor structure of the Readiness to Change Questionnaire-Treatment Version (RCQ[TV]) in a large sample (N = 742) of individuals in treatment for alcohol problems who were given the RCQ[TV] at baseline, 3-months and 12-months follow-up. Confirmatory factor analysis of the previously reported factor structure (5 items for each of Precontemplation, Contemplation and Action scales) resulted in a relatively poor fit to the data. Removal of one item from each of the scales resulted in a 12-item instrument for which goodness-of-fit indices were improved, without loss of internal consistency of the three scales, on all three measurement occasions. Inspection of relationships between stage allocation by the new instrument and negative alcohol outcome expectancies provided evidence of improved construct validity for the revised edition of the RCQ[TV]. There was also a strong relationship between stage allocation at 3-months follow-up and outcome of treatment at 12 months. The revised edition of the RCQ[TV] offers researchers and clinicians a shorter and improved measurement of stage of change in the alcohol treatment population

Towards a new paradigm of care: the International Declaration on Youth Mental Health.

A recent and growing body of evidence on young people\u27s mental health has pointed to the need for an international response to the increasing and concerning rates of mental ill-health among young people.[1, 2] The periods of adolescence and emerging adulthood[3] are considered the peak periods for the onset of mental ill-health[4] with 75% of all adult diagnoses of mental ill-health having had an onset before the age of 25 years.[5] In an era when the physical health of young people has never been better,[6] their psychological and mental health has never been worse.[7] This leaves young people vulnerable to developing potentially intractable and enduring mental health difficulties with the inevitable personal, familial, social and vocational consequences that accompany the experience of mental ill-health.[4, 8] In spite of growing concerns about young people\u27s mental health, service provision for young people remains largely inadequate and unsuited to their needs. A number of systemic factors can be implicated in insufficient and unsuitable mental health service provision for young people. Internationally, there has been an endemic failure to invest in mental health across the lifespan with an average global spend on mental health of less than $US3 per capita per year.[9] This global underinvestment brings with it particular challenges in relation to the level of priority afforded to youth mental health and the concurrent commitment needed to respond to the scale of young people\u27s mental health needs. Even in developed countries where mental health services exist, there are widespread problems with services targeting young people. Primary care and other front line community agencies can struggle to respond to high levels of need, often with little support from specialist mental health services. Specialist mental health services have traditionally followed a paediatric-adult split, with child and adolescent services offering intervention until the largely arbitrary ages of 16 or 18 years and adult services taking all young people 18 years and older.[1] In many instances, there have been gaps in service provision between the ages of 16 and 18 years.[10] This has resulted in many young people being unable to access specialist mental health support during these critical years along with high rates of attrition and dissatisfaction by young people during this transitional period.[11, 12] With a recognition that, in many sociocultural contexts, the transition from adolescence to adulthood is a variable one that spans a period from the mid-teens to the mid- to late-20s,[13] both young people and youth mental health advocates have called for a reorganization of mental health services to mirror this extended developmental period for young people.[2] Not surprisingly, there has been a trend of poor help seeking and engagement by young people in mental health services.[14, 15] A key challenge remains in supporting young people to reach out for help when they need it and early evidence suggests that factors such as ease of access, the physical environment, location, atmosphere, branding and peer influence can promote help seeking among young people.[12] It must be noted, however, that even when services are youth friendly and appropriate to their needs, individual and psychological factors strongly influence help-seeking behaviour among young people experiencing emotional or psychological distress.[16, 17] From both an economic[18] and a human impact perspective, there is a strong rationale to invest in efforts to tackle the reality of mental ill-health among the youth population.[2] Efforts to establish a new youth mental health paradigm have already begun and are gaining momentum internationally, reflected most recently in the establishment of a new International Association for Youth Mental Health (http://www.iaymh.org). The first International Youth Mental Health Conference was held in Melbourne, Australia, in 2010 and the second is being held in 2013 in Brighton, the UK (http://www.iaymh2013.com). Those involved in the youth mental health movement recognize that positively impacting on young people\u27s mental health trajectories requires transformative change. Along with a need for early promotion, detection and intervention, stemming the tide of mental ill-health among young people requires a fundamental change in how we think about young people and their mental health. It demands that we challenge traditional approaches to service development and delivery and replace them with approaches that are inclusive and empowering for young people and their families. Young people and their families need to be involved in designing and implementing more creative, responsive, accessible and youth-friendly mental health services that have the capacity to meet their needs

LHC sensitivity to lepton flavour violating Z boson decays

We estimate that the LHC could set bounds BR(Z -> mu^\pm e^\mp) < 4.1 * 10^{-7} and BR(Z -> tau^\pm mu^\mp)< 3.5 * 10^{-6} (at 95% C.L.) with 20 inverse fb of data at 8 TeV. A similar sensitivity can be anticipated for Z -> tau^\pm e^\mp, because we consider leptonic tau decays such that Z -> tau^+ mu^- gives e^+ \mu^- +$ invisibles. These limits can be compared to the LEP1 bounds of order 10^{-5} to 10^{-6}. Such collider searches are sensitive to a flavour-changing effective Z coupling which is energy dependent, so are complementary to bounds obtained from tau to 3mu and mu to 3e.Comment: 11 pages, 2 figures, version for publicatio