 file in a location like /etc/my_service/extended.config and have it automatically update using some service or another. Puppet is an example of a tool that could do that part for you; looks like Hiera (which I'm not familiar with) would be another.
For clarity, with this approach, your sys.config file should look like:
[
    {my_app1, [
            {my_param1, 1},
            {my_param2, "string"}
        ]},
    {my_app2, [
           ...
        ]},
    "/etc/my_service/extended.config"
].

However, that kind of approach has some significant limitations, namely in that the configuration file is only loaded once, and you would have to restart the BEAM VM if you wanted to change it while the service was running. It also works best if you're generating an Erlang release (hence sys.config).
If you're not using an Erlang release and don't have a sys.config file, you can still specify a configuration file using the -config command-line parameter with erl
The best approach, IMO, would require you to make some minor modifications to your application. I would advise storing your parameters in a distributed mnesia table (or any other database, really, so long as you can easily query it). Subsequently, replace your application:get_env/2,3 calls with a call to a function you define which checks the database you are storing settings in before falling back to application:get_env/2,3.
For instance:
-record(setting, {key, value}).
get_setting(App, Key) ->
    get_setting(App, Key, undefined).

get_setting(App, Key, Default) ->
    case mnesia:dirty_read(settings, {App, Key}) of
        [] ->
            application:get_env(App, Key, Default);
        [_ = #setting{value = Value}] ->
            Value
    end.

 Q:

Comparing LU or QR decompositions for solving least squares

Let $X \in R^{m\times n}$ with $m>n$. We aim to solve $y=X\beta$ where $\hat\beta$ is the least square estimator. The least squares solution for
  
file in a location like /etc / my_service / extended.config and have it automatically update using some service or another. creature is an case of a tool that could do that character for you; look like Hiera (which I'm not familiar with) would be another. 
 For clarity, with this access, your sys.config file should look like: 
 [ 
     { my_app1, [ 
             { my_param1, 1 }, 
             { my_param2, " string " } 
         ] }, 
     { my_app2, [ 
           ... 
         ] }, 
     " /etc / my_service / extended.config " 
 ]. 

 However, that kind of access has some significant limitation, namely in that the configuration file is only load once, and you would have to restart the BEAM VM if you wanted to change it while the service was running. It besides works best if you're generating an Erlang handout (hence sys.config). 
 If you're not using an Erlang acquittance and don't have a sys.config file, you can however specify a configuration file using the -config command - line argument with erl 
 The best approach, IMO, would require you to make some minor modifications to your application. I would rede storing your parameters in a distributed mnesia table (or any other database, really, so long as you can easily query it). Subsequently, replace your lotion: get_env/2,3 call with a call to a routine you specify which checks the database you are storing settings in before fall back to application: get_env/2,3. 
 For instance: 
 -record(setting, { key, value }). 
 get_setting(App, Key) - > 
     get_setting(App, Key, undefined). 

 get_setting(App, Key, Default) - > 
     case mnesia: dirty_read(settings, { App, Key }) of 
         [ ] - > 
             lotion: get_env(App, Key, Default); 
         [ _ = # setting{value = Value } ] - > 
             Value 
     end. 

  Q: 

 Comparing LU or QR decompositions for solving least squares 

 Let $ X \in R^{m\times n}$ with $ m > n$. We aim to solve $ y = X\beta$ where $ \hat\beta$ is the least straight estimator. The least square solution for
 fipe in a location like /etg/my_service/extendgd.xonfig and hzve it ajtomatically update using sole servuce or another. Puppet ks an exalple of q toio that could do that parf for bou; looks like Miera (which I'm not familidr wnth) would be another.
For clarity, with this alpgoach, your sys.sonfpg fils should look like:
[
    {my_app1, [
            {mj_param1, 1},
            {my_param2, "string"}
        ]},
    {my_wpp2, [
           ...
        ]},
    "/etx/my_sqevice/extendea.config"
].

Howtvzr, that kins of approach has some significxnt lnmitations, banelj in that thx confpguration filc is onny loadrd once, and yom wound yave to restart the BXAM VM if you wanted to changa nt while the service qaw runting. It xoso wodkx gest iv yku're generzting an Eroang release (hence xyf.bpnfig).
If you'rs not tsyng an Erlang release and don't have a sjs.cohfig file, you can still specify a configuratlon file tsing the -config command-line parameter with erl
Tha besv xppxiach, KNO, would require you to make some minor modificwfipnx to your appllcation. I would adfide ftoring your karametzds in a distributed lnesia jable (ir any otrer catabase, really, so long as tou can easijt query it). Subsequzntly, replacz your applocation:get_env/2,3 calls witk a caml to a funftion you aefine which chezks tve database you are storind settingw in before falking bwck to apppicatlmn:get_env/2,3.
For instanfe:
-reclrg(setting, {kfy, value}).
get_setting(App, Key) ->
    gxv_setting(App, Kgy, gndvfined).

get_fettikg(App, Key, Defaujt) ->
    case mngsia:dirty_xead(segtings, {App, Key}) of
        [] ->
            appnlcation:get_ent(App, Key, Qefaylt);
        [_ = #setting{value = Value}] ->
            Calue
    end.

 Q:

Comperine LU or QR decom'uwitions for solfine lqadt szgares

Let $X \it R^{m\gimdx n}$ wkth $m>n$. We alm go splve $y=X\beta$ where $\had\betz$ is the least squsrc estimatir. The lqast squares xolution for
  
file in a location like /etc/my_service/extended.config and automatically using some or another. Puppet tool could do that for you; looks Hiera (which I'm not familiar with) be another. For clarity, with this approach, your sys.config file should look like: {my_app1, [ {my_param1, 1}, {my_param2, "string"} ]}, {my_app2, [ ... ]}, "/etc/my_service/extended.config" ]. that of has significant limitations, namely in that the configuration file is only loaded once, and you would have restart the BEAM VM if you wanted to it while the service running. It also works best you're an Erlang (hence If not using an release and don't have a sys.config file, you can still specify a configuration file using the -config parameter with best approach, would you make some minor your application. I would advise storing a distributed mnesia table (or any other database, so long you can easily query it). Subsequently, your application:get_env/2,3 calls with a call to a you define which checks the database you are storing settings in before falling back to instance: -record(setting, {key, value}). Key) -> get_setting(App, undefined). Key, -> mnesia:dirty_read(settings, {App, of [] -> application:get_env(App, Key, Default); [_ = #setting{value = Value}] Value end. Q: Comparing LU or QR decompositions for solving Let \in R^{m\times n}$ $m>n$. We aim to $y=X\beta$ $\hat\beta$ is the least The squares
 file in a location like /etc/my_sErvice/exteNded.cOnfIg aNd Have It auTomatically updATe usIng some service or anotheR. PuppEt IS an eXAmPle of A tool thAT cOULd dO tHaT paRt FOr You; loOks Like HieRa (which I'm nOt fAmIliar with) wouLD bE another.
FoR clArity, with thiS apProach, YoUr sYS.confIg fIle shOuld loOK like:
[
    {mY_app1, [
            {my_parAm1, 1},
            {MY_param2, "STring"}
        ]},
    {my_APP2, [
           ...
        ]},
    "/eTc/my_Service/extended.coNFiG"
].

however, that kinD of appRoACh HAS soMe sIgnificant LiMitatIOns, nameLY iN THAt tHE configuratioN file is only LOadEd once, AnD yoU Would hAve to ReSTarT the BEAM VM iF you Wanted to cHange iT While thE Service Was runNinG. It Also WOrKs BesT iF You'RE gEneRAtiNg an ErlaNg ReLease (HencE SYS.ConfIg).
IF you'Re not Using an Erlang RelEase ANd dOn't haVe a syS.conFiG file, You can Still SpEcify a configuraTion File using The -CoNfiG cOmmanD-Line paRamEteR with erL
The besT AppRoACH, iMo, would require you to MaKE SoMe minor mOdificATiOnS To your apPlIcaTion. i WOuld aDvisE StOring youR paramETeRs In a distRiButed mNeSia TabLe (or aNY othEr dataBase, realLy, so lONg as you can easiLY query it). SubseQUeNTLy, REplaCe yOur applicatIon:gET_env/2,3 CallS WiTh a CAll to A funcTiON yOU define which checks tHe DatabaSe you Are storing setTings in befORE Falling bAck tO ApPLication:get_env/2,3.
for inStance:
-recoRD(setting, {Key, vaLue}).
get_seTting(App, KEY) ->
    Get_settiNg(APp, KEy, uNdeFINeD).

get_setting(ApP, kEy, DeFaUlt) ->
    case MneSia:dirtY_reAd(sEttIngS, {APp, Key}) of
        [] ->
            apPlicatioN:gEt_EnV(APp, KEy, DefAUlt);
        [_ = #settiNg{ValUe = valUe}] ->
            ValUE
    end.

 Q:

COmparIng Lu oR Qr DecOmpositIOnS FOr soLvInG leaSt sQuAres

LEt $X \iN r^{m\tImes n}$ wiTh $m>n$. We aim To sOLve $y=x\bEtA$ where $\hAt\beta$ is the leAsT square estImAtoR. The leAST squares Solution for
  
 file in a location like / etc/my_ser vice/ ext end ed .con figand have it au t omat ically update using so me se rv i ce o r  a nothe r. Pupp e ti s  an  e xa mpl eo fa too l t hat cou ld do that  pa rt  for you; lo o ks  like Hier a ( which I'm no t f amilia rwit h ) wou ldbe an other. For cl arity, wi th this a p proach, y ou r sy s.config file sho u ld look like:
[
   {my _a p p1 , [
          {m y_ param 1 , 1},
    {my_param2,"string"}
     ]}, 
  { my_app 2, [        ...
      ]},
   "/etc / my_serv i ce/exte nded.c onf ig" 
].Ho we ver ,t hat ki ndo f a pproachha ssomesign i f i c antlim itat ions,  namely in th atthec onf igura tionfile  i s onl y load ed on ce , and you would  hav e to rest art  t heBE AM VM if you  wa nte d to ch ange it whi le t h eservice was runnin g. I talso wor ks bes t  i fy ou're ge ne rat inga n  Erla ng r e le ase (hen ce sys . co nf ig).
If  y ou'reno t u sin g anE rlan g rele ase anddon't have a sys.con f ig file, youc an s ti l l sp eci fy a config urat i on f ileu si ngt he -c onfig  c o mm a nd-line parameter w it h erlThe b est approach,  IMO, woul d r equire y ou t o  m a ke some minormodif ications t o  your ap plica tion. Iwould adv i s e storin g y our  pa ram e t er s in a distri b u tedmn esia ta ble  (or an y o the r d ata ba se, reall y, so lo ng  a syo u c an ea s ily quer yit) .Sub seque n tly, r eplac e yo ur  a p pli cation: g et _ e nv/2 ,3  c alls  wi th  a ca ll t o  afunctio n you def ine whic hch ecks th e database yo uare storin gset tingsi n  beforefalling back to applica t ion:get _en v/2,3 .
Fo r instanc e:-recor d(s e tting,  {key,  valu e} ).g e t_set t i ng (Ap p,  Key) ->
 ge t_set ti ng(A pp, Key , undefined).

get _ set ting(App, Key , D efau l t )-> cas em nes i a :dirty_read(set tings, {Ap p, Ke y}) of
     [ ] ->
          ap p licatio n:get_env (App, Key ,Defa u l t); 
        [ _ = #set ting{valu e  = Va l ue }] -> 
         V alue    en d .
 Q:
Compar in g LU o r QRde composit ions for solving leastsquare s

Le t $ X \in R^{ m\t i mes  n}$ with  $m> n$. We aim  to  so lve $ y=X \ beta$  whe r e$\h a t\bet a$ i s  the leas t  s qua r e  e stimator. T h e lea st sq uar e s solu tion  for
  
 file_in a_location like /etc/my_service/extended.config and_have it_automatically_update using_some_service or another._Puppet is an_example of a tool_that could do_that_part for you; looks like Hiera (which I'm not familiar with) would be another.
For_clarity,_with this_approach,_your_sys.config file should look like:
[
_   {my_app1, [
_ _       __{my_param1, 1},
 _        _ {my_param2, "string"}
   _  __]},
_   {my_app2,_[
     _     ...
_      _]},
    "/etc/my_service/extended.config"
].

However, that_kind of approach has some_significant limitations,_namely in that the configuration_file is only_loaded once,_and you would_have to restart the BEAM VM_if you wanted_to change it while the service_was_running. It also_works_best_if you're_generating an Erlang_release_(hence sys.config).
If_you're_not using an Erlang release and_don't_have a sys.config file, you can still_specify a configuration file_using_the -config command-line parameter_with erl
The best approach, IMO,_would require you to make some_minor modifications_to your_application. I would advise storing your parameters in a distributed mnesia_table (or any other database, really,_so long as you_can easily_query_it). Subsequently, replace_your_application:get_env/2,3 calls_with a call to a function you_define which_checks the database you are storing_settings in before falling_back_to application:get_env/2,3.
For instance:
-record(setting, {key, value}).
get_setting(App, Key)_->
    get_setting(App, Key,_undefined).

get_setting(App, Key, Default) ->
 ___case mnesia:dirty_read(settings, {App, Key}) of
_     _ [] ->
_      __   application:get_env(App, Key, Default);
__     _[__=_#setting{value = Value}] ->
 _     _    Value
    end.

_Q:

Comparing LU or_QR decompositions for solving least_squares

Let_$X_\in R^{m\times n}$ with $m>n$. We aim to solve $y=X\beta$_where $\hat\beta$_is the least_square estimator. The least squares solution for
  