CD-EXCALIBUR-FMS0065-M7.3_SoftwareSupportComplementaryActions2
==============================================================

.. meta::
   :description: technical note

   :keywords: ExCALIBUR,Software,Support,Complementary,Actions,2,M7.3,Version,1.00,Abstract,The,report,describes,work,for,ExCALIBUR,project,NEPTUNE,at,Mile-,stone,M7.3.,It,describes,aspects,of,coordination,within,the,NEPTUNE,project,not,covered,in,previous,Year,3,reports,,namely,,the,development,of,a,GitHub,repository,for,infrastructure,code,and,project,planning;,the,devel-,opment,of,a,project,website,for,knowledge,transfer,within,NEPTUNE;,and,a,description,of,collaborations,arising,from,NEPTUNE-related,interactions,,including,the,Fusion,Modelling,Use,Case,working,group,established,create,a,connection,between,Project,NEPTUNE,and,the,wider,ExCALIBUR,pro-,gramme.,UKAEA,REFERENCE,AND,APPROVAL,SHEET,Client,Reference:,UKAEA,Reference:,CD/EXCALIBUR-FMS/0065,Issue:,Date:,1.00,18,March,2022,Project,Name:,ExCALIBUR,Fusion,Modelling,System,Prepared,By:,Name,and,Department,Joseph,Parker,Wayne,Arter,Signature,N/A,N/A,Date,18,March,2022,18,March,2022,BD,Reviewed,By:,Wayne,Arter,18,March,2022,Project,Technical,Lead,1,1,Introduction,Activity,7,“Support,and,Coordination”,is,a,programme,providing,support,and,coordinating,work,internally,to,complement,Activity,3,,and,initiating,Software,Support,Procurement,to,ensure,conti-,nuity,of,external,work.,The,main,focus,of,the,work,is,to,facilitate,the,production,of,a,DSL,tailored,to,NEPTUNE,requirements,,to,consider,how,best,to,couple,NEPTUNE-developed,software,with,other,codes,,and,to,determine,how,and,when,to,benchmark,NEPTUNE,software,against,pre-,existing,tokamak,edge,modelling,software.,In,addition,,this,project,provides,management,of,external,research,,coordinating,the,additional,expert,input,in,support,of,the,numerical,analysis,project,around,the,topics,of,matrix,precondition-,ing,,asymptotic-preserving,methods,and,multirate/Variable,Stepsize-Variable,Order,timestepping,algorithms,to,both,spectral/hp,element,and,particle-based,methods.,As,such,,Support,and,Coordination,contributes,primarily,to,Work,Package,4,“Code,structure,and,coordination”,(FM-WP4,from,the,Fusion,Modelling,System,Science,Plan,[1]),,with,some,work,falling,under,the,remits,of,FM-WP1,“Numerical,representation”,,and,of,the,cross-cutting,packages,XC-WP1,“Common,approaches,&,solutions”,and,XC-WP2,“Emerging,technologies”.,In,particular,,this,year’s,work,focussed,on,novel,timestepping,methods,,performance,benchmark-,ing,,and,matrix,preconditioning.,Previous,Year,3,Support,and,Coordination,reports,covered,pro-,curement,of,mathematical,support,for,advanced,timestepping,and,asymptotic-preserving,methods,[2],,and,benchmarking,and,code,coupling,[3].,Further,reports,from,grantee,work,are,due,at,the,end,of,the,Financial,Year,and,so,will,be,reported,on,at,a,later,date.,This,report,describes,other,work,undertaken,to,coordinate,and,foster,collaboration,within,the,NEP-,TUNE,community.,In,Section,2.1,we,describe,work,setting,up,a,repository,for,NEPTUNE,code,,prototyping,working,practices,,and,writing,a,prototype,software,framework,in,Data,Parallel,C++,In,Section,2.2,we,describe,the,development,of,the,Project,NEPTUNE,website,,de-,(DPC++).,signed,to,act,as,a,record,of,project,planning,and,management,,and,to,facilitate,knowledge,trans-,fer,among,project,participants.,In,Section,2.3,we,describe,the,activities,of,a,working,group,set,up,in,support,of,the,ExCALIBUR,Fusion,Modelling,Use,Case,,bringing,together,UKAEA,staff,,NEPTUNE,grantees,and,external,partners,from,STFC,and,academia.,In,Section,2.4,we,describe,ongoing,collaborations,arising,from,Project,NEPTUNE,but,not,due,specifically,to,other,Activities.,Finally,,in,Section,3,,we,summarize.,2,Task,Work,2.1,PolyRepoPracticeCore,The,NEPTUNE,development,philosophy,is,“separation,of,concerns”,,where,domain,specialists,write,proxyapps,that,focus,on,some,aspect,of,the,overall,code.,Production,of,proxyapps,is,ongoing,in,accordance,with,the,Science,Plan,[1].,These,proxyapps,need,to,be,drawn,together,into,a,single,coherent,codebase,,something,that,requires,infrastructure,both,for,code,coupling,and,for,code,maintenance,and,testing.,2,As,recommended,in,[4],,each,proxyapp,will,be,hosted,in,a,separate,GitHub,repository,under,the,NEPTUNE,organization.,Then,a,main,NEPTUNE,repository,hosts,software,to,interface,the,proxyapps,,which,pulls,in,the,proxyapps,as,git,submodules.,This,enables,separation,of,concerns,as,a,proxyapp’s,developer,can,focus,largely,on,their,own,work,,making,pull,requests,,raising,issues,etc.,in,their,proxyapp’s,repository,without,extraneous,pull,requests,,issues,and,project,planning,relating,to,other,proxyapps.,The,main,repository,is,then,the,place,for,discussions,relating,to,interactions,between,proxyapps.,For,example,,a,bug,fix,in,a,proxyapp,would,lead,to,an,issue,in,its,own,local,repository,,but,if,the,fix,would,change,the,proxyapp’s,expected,output,or,external,API,,it,would,lead,to,an,issue,in,the,main,NEPTUNE,repository.,To,prototype,ideas,and,refine,working,practices,,this,main,repository,has,been,created,[5].,This,repository,is,being,used,to,host,development,of,infrastructure,code,(I/O,,build,systems,,testing,frameworks),,project,planning,(issues,and,kanban,boards),and,a,prototype,framework,for,the,NEPTUNE,physics,software.,The,software,presently,targets,the,solution,of,the,1+1D,Vlasov–,Poisson,system,using,a,particle-in-cell,(PIC),method,,since,this,is,a,well-studied,and,benchmarked,system,with,many,existing,test,problems,and,implementations.,The,implementation,is,modular,,allowing,other,physical,systems,to,be,solved,by,changing,the,information,passed,to,the,particle,pusher,and,elliptic,solver.,Similarly,,the,dimensionality,and,geometry,of,the,problem,may,be,changed,by,defining,new,implementations,of,the,classes,Mesh,,In,particular,,the,space,and,velocity,space/particle,implementations,are,Space,and,Velocity.,separated,so,that,it,is,possible,to,add,the,option,of,spectral/hp,implementations,in,space,alongside,the,grid-based,approach,already,implemented.,Thus,it,will,be,possible,to,rapidly,prototype,a,spectral/hp,in,space,+,PIC,code,when,a,Nektar++,API,becomes,available,through,NEPTUNE,project,work.,2.1.1,SYCL,parallelization,The,prototype,code,is,parallelized,using,oneAPI’s,DPC++/SYCL,implementation,[6].,The,conclu-,sions,from,this,exercise,are,mixed.,The,process,of,parallelizing,a,small,serial,code,with,DPC++,is,moderately,straightforward.,On,a,local,machine,,the,code’s,integrated,test,that,took,12,seconds,on,a,single,thread,before,parallelization,,ran,in,just,over,3,seconds,on,4,threads,,with,no,optimizations,besides,replacing,normal,for,loops,with,SYCL’s,parallel,for.,The,developer,experience,however,was,less,positive.,While,much,documentation,is,provided,by,Intel,,it,is,not,always,clear,which,documents,are,current,,and,which,approaches,and,coding,styles,are,recommended.,There,is,a,library,of,sample,code,[7],but,this,often,proposes,multiple,approaches,to,the,same,problem,,without,making,clear,which,approach,is,best.,For,example,,the,sample,reduction,code,provides,six,different,methods,for,performing,a,reduction,from,a,vector,to,a,number.,However,,there,is,no,library,function,for,performing,a,reduction,into,a,vector,(such,as,a,sum,all,reduce),,and,this,had,to,be,implemented,manually,in,the,prototype,code.,In,addition,the,language,is,very,verbose,,and,it,seems,unlikely,that,details,of,the,SYCL,implementation,could,be,fully,abstracted,from,the,rest,of,the,code,without,using,macros.,3,2.2,NEPTUNE,Website,A,vital,aspect,of,support,and,coordination,is,to,ensure,that,accurate,,up-to-date,technical,infor-,mation,concerning,the,entire,ExCALIBUR,project,NEPTUNE,is,available,to,all,the,community.,It,has,been,argued,[8],that,this,is,best,met,by,means,of,a,website,,see,ref,[9].,Work,has,continued,to,develop,the,website,,primarily,directed,towards,design,of,the,NEPTUNE,software,,since,the,two,reports,appeared,in,October.,There,is,now,a,GitHub,action,to,verify,that,all,input,is,in,ASCII.,The,high-level,website,structure,is,summarised,as,follows:,PN,Program,name,-,analogous,to,book,title,and,preface,,contains,important,administrative,in-,formation,BD,Business,design,-,analogous,to,book,flyleaf,or,introductory,chapter,,designed,to,‘sell’,the,project,to,potential,customers,RB,Requirements,baseline,-,where,use,cases,define,functional,requirements,TS,Technical,specification,-,documents,decisions,taken,to,meet,functional,requirements,,in-,cludes,non-functional,requirements,such,as,software,standards,and,conventions,DJF,Design,justification,file,-,place,to,store,all,ideas,considered,to,meet,spec.,DDF,Design,definition,file,-,definition,of,software,using,selected,ideas,MGT,Management,file,-,contribution,from,ref,[4],MF,Maintenance,file,-,not,yet,needed,OP,Operational,documentation,-,contribution,from,ref,[4],REF,Reference,Material,-,to,ensure,consistency,of,usage,of,mathematical,notation,,acronyms,and,terminology,(‘ontology’),IND,Index,-,only,needed,in,absence,of,search,engines,It,is,envisaged,that,this,structure,will,cascade,down,to,proxyapps,,which,will,be,able,to,link,up-,wards,to,common,material,such,as,in,item,REF,above,,in,order,to,minimise,the,amount,of,new,documentation,to,be,produced.,All,entries,have,been,overhauled,as,part,of,the,ongoing,work.,Item,RB,now,contains,order-of-,magnitude,estimates,for,physical,quantities,relevant,to,tokamak,edge,modelling,and,use,cases,for,NEPTUNE,devised,by,each,member,of,the,team.,These,cases,are,intended,to,be,relevant,to,the,needs,of,a,physicist,,a,design,engineer,,a,finite,element,expert,and,a,particle,specialist,respectively.,Item,TS,now,includes,order-of-magnitude,estimates,for,calculation,costs,of,highly,detailed,edge,computations.,DJF,has,a,list,of,reports,and,a,brief,survey,of,each,report’s,contents,is,in,the,process,of,being,added.,Item,REF,has,been,considerably,expanded,,so,that,there,are,now,over,300,acronyms,covering,both,the,highly,technical,(e.g.,SSA,for,Singular,Spectrum,Analysis),to,the,purely,administrative,4,Figure,1:,Result,of,a,search,for,“Uncertainty,Quantification”,of,NEPTUNE,reports,,using,DOCFETCHER,software.,Search,made,on,15,March,2022,of,current,GitHub,repository.,(e.g.,RO,for,Responsible,Officer),,and,over,350,mathematical,symbols,listed,,each,now,with,physi-,cal,units,where,appropriate.,A,convention,for,converting,the,LATEX,representations,to,ASCII,for,use,in,C++,has,been,devised,as,a,stopgap,pending,an,agreed,,detailed,design,of,a,class,hierarchy.,Considerable,effort,,involving,all,the,UKAEA,NEPTUNE,team,and,external,Nektar++,experts,,has,been,put,into,designing,a,class,or,object-oriented,hierarchy,,preliminary,results,from,which,have,been,added,to,the,website,under,item,DDF.,Information,has,been,extracted,from,internal,reports,where,appropriate,,in,particular,,the,items,MGT,and,OP,have,been,filled,as,indicated,above,,by,information,from,ref,[4].,Elsewhere,links,have,been,provided,to,pre-existing,repository,material,in,LATEX,using,the,LATEX,\input,command,,and,a,larger,number,of,citations,now,has,links,to,the,web.,All,approved,NEPTUNE,reports,by,both,UKAEA,and,the,grantees,have,been,placed,in,the,GitHub,repository,[10],,although,access,to,it,is,controlled,and,users,who,are,not,logged,into,GitHub,(or,who,do,not,have,a,GitHub,account),will,get,an,‘Error,404’.,Ultimately,it,is,hoped,that,all,reports,for,which,LATEX,source,has,been,provided,,will,be,more,tightly,linked,to,the,website.,However,,currently,it,is,recommended,that,the,GitHub,repository,contents,be,‘pulled’,to,a,local,machine,and,indexed,by,a,desktop,search,engine,such,as,DOCFETCHER,[11],or,RECOLL,[12].,Figure,1,shows,the,result,of,a,test,search.,2.3,Fusion,Modelling,Working,Group,The,Fusion,Modelling,Working,Group,is,a,new,working,group,of,people,involved,in,the,UKAEA,Fusion,Modelling,Science,Use,Case,(part,of,the,wider,ExCALIBUR,programme).,Currently,15,5,people,are,involved,,9,from,Project,NEPTUNE,(6,UKAEA,staff,and,3,from,Nektar++),,3,from,STFC,(including,the,chair,Stephen,Longshaw),,2,from,the,University,of,Cambridge,and,1,from,the,University,of,York.,The,STFC,members,are,all,involved,in,a,number,of,EPSRC,ExCALIBUR,projects,–,most,notably,“Integrated,Simulation,at,the,Exascale:,coupling,,synthesis,and,performance”,–,but,all,of,which,include,an,element,of,fusion,modelling.,The,purpose,of,this,group,is,to,highlight,areas,of,ongoing,work,,fostering,new,collaboration,and,prevent,duplication,of,efforts.,An,inaugural,(virtual),meeting,was,held,on,11th,February,2022.,The,meeting,began,with,a,round,table,of,individuals’,interests,and,relevant,project,involvement.,Interests,naturally,covered,a,broad,range,of,plasma,physics,topics,(e.g.,magnetohydrodynamics,,gyrokinetics,,PIC,codes,,plasma-,wall,interactions),,as,well,as,related,physics,(e.g.,complex,gas,dynamics,,smoothed,particle,hy-,drodynamics,,strongly,anisotropic,systems),and,code,development,topics,(e.g.,fluid-to-particle,code,coupling,,grid,generation,for,spectral/hp,,uncertainty,quantification,,software,development,practices).,The,discussion,then,moved,on,to,what,the,working,group,could,achieve,,and,what,it,could,do,to,support,NEPTUNE,and,wider,fusion,projects.,The,following,suggestions,were,proposed:,•,creation,of,a,living,document,on,coupling,methods,to,inform,the,Project,NEPTUNE,•,definition,of,data,structures,used,to,pass,information,internally,between,the,components,of,NEPTUNE,•,definition,of,a,working,schema,for,output,from,fusion,modelling,,similar,to,that,which,exists,for,climate,modelling,(and,investigation,into,whether,the,IMAS,framework,(summarized,in,a,previous,NEPTUNE,report,[3]),is,appropriate,for,this),•,work,to,determine,appropriate,input/output,file,formats,for,NEPTUNE,•,work,on,the,delivery,of,software/package,management,,in,support,of,the,existing,work,pack-,age,for,delivering,reproducible,coupled,software,and,workflows,as,part,of,ExCALIBUR,cross-,cutting,project,on,code,coupling,It,was,a,agreed,that,the,working,group,should,not,introduce,too,many,new,meetings,,and,where,possible,collaborative,working,should,be,favoured,over,meetings.,Future,meetings,will,occur,roughly,monthly,,but,will,be,themed,so,only,those,interested,need,attend.,More,general,,larger,meetings,will,be,held,on,a,six-monthly,basis.,To,facilitate,collaborative,working,,a,group,Slack,channel,was,made,(as,a,channel,with,the,NEP-,TUNE,Slack,workspace).,A,git,repository,[13],was,also,created,under,the,ExCALIBUR-NEPTUNE,GitHub,organization.,2.4,Grantee,collaborations,There,are,two,pieces,of,grantee,work,under,the,remit,of,Support,and,Coordination,which,are,due,by,the,end,of,the,financial,year,2021/22,,and,which,will,appear,in,the,NEPTUNE,documents,6,repository,[10],after,review.,The,first,of,these,is,updates,to,the,reports,on,approaches,to,per-,formance,portability,[14,,15,,16],giving,recent,developments,in,the,software,and,hardware,for,Exascale.,The,second,is,a,report,describing,the,use,of,ReFrame,as,a,framework,for,performance,benchmarking,(ReFrame,was,discussed,briefly,in,NEPTUNE,report,[3]).,In,addition,,there,are,a,number,of,new,collaborations,arising,from,Project,NEPTUNE,,either,result-,ing,from,project,definitions,or,from,new,connections,made,via,the,NEPTUNE,progress,meetings.,Of,these,,the,collaboration,between,STFC,and,the,University,of,Oxford,on,matrix,preconditioning,falls,within,the,scope,of,the,Support,and,Coordination,activity,,and,is,described,in,the,following,subsection.,2.4.1,STFC,and,Oxford:,matrix,preconditioning,As,a,result,of,the,Matrix,Preconditioning,project,(NEPTUNE,ITT,T/NA084/20),,STFC,(Sue,Thorne,,Tyrone,Rees,,Hussam,Al,Daas,,Andrew,Sunderland,,Emre,Sahin,,Vassil,Alexandrov),have,an,on-,going,collaboration,with,the,University,of,Oxford,(Patrick,Farrell).,The,collaboration,focusses,on,the,application,of,new,preconditioning,techniques,for,FEM,in,NEPTUNE-relevant,problems.,Ini-,tial,work,presented,at,a,NEPTUNE,progress,meeting,in,March,2022,,considered,solving,a,2D,Poisson,problem,using,the,continuous,Galerkin,method,with,different,preconditioners:,(1),an,al-,gebraic,two-level,Schwarz,preconditioner,recently,derived,by,the,STFC,team,[17];,and,(2),the,long-established,algebraic,multigrid,preconditioner,[18],as,implemented,in,parallel,with,Boomer-,AMG,in,HYPRE,[19].,The,2D,Poisson,test,problem,was,implemented,in,Firedrake,[20],and,used,13th,order,continuous,Galerkin,on,an,80,by,80,Cartesian,grid,,giving,a,total,problem,size,of,1,,083,,6812.,This,was,paral-,lelized,on,256,cores.,The,algebraic,multigrid,implementation,took,744,iterations,and,18.7s,seconds,to,converge,to,a,tolerance,of,10−7.,In,contrast,,the,algebraic,two-level,Schwarz,preconditioner,re-,quired,only,23,iterations,and,2.1,seconds,to,reach,the,same,tolerance,,a,reduction,in,the,number,of,iteration,of,∼,×30,and,a,speed,up,of,∼,×9.,3,Summary,This,report,summarizes,work,undertaken,as,part,of,the,Year,3,“Support,and,Coordination”,Activity,that,have,not,been,described,in,the,previous,reports,[2,,3].,The,report,discusses,activities,which,enable,collaboration,and,knowledge,transfer,,namely,the,creation,of,a,Project,NEPTUNE,software,repository,(Section,2.1),and,website,(Section,2.2).,Further,,it,discusses,collaborations,which,either,support,the,NEPTUNE,project,or,have,arisen,from,NEPTUNE,project,work,,namely,the,Fusion,Modelling,Use,Case,working,group,(Section,2.3),and,other,collaborations,between,NEPTUNE,grantees,(Section,2.4).,Grantee,work,due,to,be,submitted,by,the,end,of,this,Financial,Year,Y3,will,be,reported,on,in,due,course.,7,Acknowledgement,The,support,of,the,UK,Meteorological,Office,and,Strategic,Priorities,Fund,is,acknowledged.,References,[1],W.,Arter,,L.,Anton,,D.,Samaddar,,and,R.,Akers.,ExCALIBUR,Fusion,Mod-,elling,System,Science,Plan.,Technical,Report,CD/EXCALIBUR-FMS/0001,,UKAEA,,2019.,https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/,research/spf/ukaea-excalibur-fms-scienceplan.pdf.,[2],J.T.,Parker,and,W.,Arter.,Literature,review,for,Call,T/AW086/21:,Mathematical,Support,for,Software,Implementation.,Technical,Report,CD/EXCALIBUR-FMS/0052-M7.1,,UKAEA,,2021.,https://github.com/ExCALIBUR-NEPTUNE/Documents/blob/main/reports/ukaea_,reports/CD-EXCALIBUR-FMS0052-M7.1.pdf.,[3],J.T.,Parker,,E.,Threlfall,,W.,Arter,,and,W.,Saunders.,Technical,Report,CD/EXCALIBUR-FMS/0053-M7.2,,marking.,UKAEA,,https://github.com/ExCALIBUR-NEPTUNE/Documents/blob/main/reports/ukaea_,reports/CD-EXCALIBUR-FMS0053-M7.2.pdf.,Code,coupling,and,bench-,2021.,[4],E.,Threlfall,and,W.,Arter.,Technical,Report,CD/EXCALIBUR-FMS/0042-M3.1.4,,UKAEA,,//github.com/ExCALIBUR-NEPTUNE/Documents/blob/main/reports/ukaea_reports/,CD-EXCALIBUR-FMS0042-M3.1.4.pdf.,2021.,Specification,and,Integration,of,Scientific,Software.,https:,[5],ExCALIBUR-NEPTUNE,PolyrepoPracticeCore,GitHub,Repository.,https://github.com/,ExCALIBUR-NEPTUNE/PolyrepoPracticeCore,,2022.,Accessed:,March,2022.,[6],J.,Reinders,,B.,Ashbaugh,,J.,Brodman,,M.,Kinsner,,J.,Pennycook,,and,X.,Tian.,Data,Parallel,C++:,Mastering,DPC++,for,Programming,of,Heterogeneous,Systems,using,C++,and,SYCL.,Springer,Nature,,2021.,[7],oneAPI,Samples,Repository.,https://github.com/oneapi-src/oneAPI-samples,,2022.,Accessed:,March,2022.,[8],W.,Arter,,J.,Parker,,and,E.,Threlfall.,Development,Plan.,Technical,Report,CD/EXCALIBUR-,https://github.com/ExCALIBUR-NEPTUNE/Documents/,FMS/0033-D3.4,,UKAEA,,2021.,blob/main/reports/ukaea_reports/CD-EXCALIBUR-FMS0033-1.10-D3.4.pdf.,[9],W.,Arter,,E.,Threlfall,,J.,Parker,,and,W.,Saunders.,Technical,Report,CD/EXCALIBUR-FMS/0054-D3.1,,UKAEA,,2021.,site.,//github.com/ExCALIBUR-NEPTUNE/Documents/blob/main/reports/ukaea_reports/,CD-EXCALIBUR-FMS0054-D3.1.pdf.,Software,Specification,Web-,https:,[10],ExCALIBUR-NEPTUNE,Bid,Documents,,Calls,,Reports,and,Notes.,https://github.com/,ExCALIBUR-NEPTUNE/Documents,,2021.,Accessed:,March,2021.,8,[11],DocFetcher,is,an,Open,Source,desktop,search,application.,http://docfetcher.,sourceforge.net/en/index.html,,2022.,Accessed:,January,2022.,[12],Recoll,finds,documents,based,on,their,contents,as,well,as,their,file,names.,https://www.,lesbonscomptes.com/recoll,,2022.,Accessed:,January,2022.,[13],Fusion,Modelling,Use,Case,GitHub,Repository.,https://github.com/ExCALIBUR-NEPTUNE/,Cross-Cutting-Organisation,,2022.,Accessed:,March,2022.,[14],S.,Wright,,B.,Dudson,,P.,Hill,,D.,Dickinson,,and,G.,Mudalige.,Approaches,to,Performance,Portable,Applications,for,Fusion.,Technical,Report,2047358-TN-01-02,,UKAEA,Project,Nep-,tune,,2021.,https://github.com/ExCALIBUR-NEPTUNE/Documents/blob/main/reports/,2047358/TN-01.pdf.,[15],S.,Wright,,B.,Dudson,,P.,Hill,,D.,Dickinson,,and,G.,Mudalige.,Identification,of,Testbed,Technical,Report,2047358-TN-02,,UKAEA,Project,Nep-,https://github.com/ExCALIBUR-NEPTUNE/Documents/blob/main/reports/,Platforms,and,Applications.,tune,,2021.,2047358/TN-02.pdf.,[16],S.,Wright,,B.,Dudson,,P.,Hill,,D.,Dickinson,,and,G.,Mudalige.,Evaluation,of,Ap-,proaches,to,Performance,Portability.,Technical,Report,2047358-TN-03,,UKAEA,Project,Nep-,tune,,2021.,https://github.com/ExCALIBUR-NEPTUNE/Documents/blob/main/reports/,2047358/TN-03.pdf.,[17],H.,Al,Daas,,P.,Jolivet,,and,T.,Rees.,Efficient,Algebraic,Two-Level,Schwarz,Preconditioner,For,Sparse,Matrices.,arXiv,preprint,arXiv:2201.02250,,2022.,[18],S.F.,McCormick.,Multigrid,methods.,SIAM,,1987.,[19],BoomerAMG,parallel,implementation,of,the,algebraic,multigrid,method.,https://hypre.,readthedocs.io/en/latest/solvers-boomeramg.html,,2022.,Accessed:,March,2022.,[20],F.,Rathgeber,,D.A.,Ham,,L.,Mitchell,,M.,Lange,,F.,Luporini,,Andrew,T.T.,Mcrae,,G.-T.,Bercea,,G.R.,Markall,,and,P.H.J.,Kelly.,Firedrake:,Automating,the,finite,element,method,by,composing,abstractions.,ACM,Trans.,Math.,Softw.,,43(3),,December,2016.,9

:pdfembed:`src:_static/CD-EXCALIBUR-FMS0065-M7.3_SoftwareSupportComplementaryActions2.pdf, height:1600, width:1100, align:middle`