python - What are the loc and scale parameters in scipy.stats.maxwell? -

-

the maxwell-boltzmann distribution given maxwell-boltzmann http://mathworld.wolfram.com/images/equations/maxwelldistribution/inline9.gif. scipy.stats.maxwell distribution uses loc , scale parameters define distribution. how parameters in 2 definitions connected? appreciate if tell in general how determine relation between parameters in scipy.stats , usual definition.

the loc parameter always shifts x variable. in other words, generalizes distribution allow shifting x=0 x=loc. when loc nonzero,

maxwell.pdf(x) = sqrt(2/pi)x**2 * exp(-x**2/2), x > 0

becomes

maxwell.pdf(x, loc) = sqrt(2/pi)(x-loc)**2 * exp(-(x-loc)**2/2), x > loc.

the doc string scipy.stats.maxwell states:

a special case of chi distribution, df = 3, loc = 0.0, , given scale = a, a parameter used in mathworld description.

so scale corresponds parameter a in equation

http://mathworld.wolfram.com/images/equations/maxwelldistribution/inline9.gif

in general need read distribution's doc string know parameters distribution has. the beta distribution, example, has a , b shape parameters in addition loc , scale.

however, believe continuous distributions, distribution.pdf(x, loc, scale) identically equivalent distribution.pdf(y) / scale y = (x - loc) / scale.


Comments

Post a Comment

Popular posts from this blog

PHP DOM loadHTML() method unusual warning -

-
i had following code works fine on localhost: $document = new domdocument(); $document->loadhtml($p_result); $form = $document->getelementsbytagname('form')->item(0); // code continues using $form variable after same code updated on outside server, loadhtml() failed , issued warning. warning: domdocument::loadhtml() expects parameter 1 valid path, string given in path/name/to/script.php returned null instead of object code pretty gets fatal error. note contents of $p_result absolutely same on outside server , on localhost. but why displays kind of warning , why not work? doesn't loadhtml() expects argument 1 string in first place? why method expects parameter 1 valid path ? just make clear i'm not calling loadhtmlfile() , i'm calling loadhtml() . thanks. you're affected one of php bugs . issue present in php 5.6.8 , 5.6.9. have affected php version on server, , bug-free version on localhost. the bug forbids null
Read more

python - How to create jsonb index using GIN on SQLAlchemy? -

-
here's current code creating index jsonb. index("mytable_data_idx_id_key", mytable.data['id'].astext, postgresql_using='gin') but got error. sqlalchemy.exc.programmingerror: (psycopg2.programmingerror) data type text has no default operator class access method "gin" hint: must specify operator class index or define default operator class data type. [sql: "create index event_data_idx_id_key on event using gin ((data ->> 'id'))"] is there way create index on sqlalchemy? the postgresql specific sqlalchemy docs @ http://docs.sqlalchemy.org/en/latest/dialects/postgresql.html#operator-classes mention postgresql_ops dictionary provide "operator class" used postgresql, , provide example illustrating use: index('my_index', my_table.c.id, my_table.c.data, postgresql_ops={ 'data': 'text_pattern_ops',
Read more

c# - TransactionScope not rolling back although no complete() is called -

-
i'm using transactionscope rollback transaction fail bool errorreported = false; action<importerrorlog> newerrorcallback = e => { errorreported = true; errorcallback(e); }; using (var transaction = new transactionscope()) { foreach (importtaskdefinition task in taskdefinition) { loader.load(streamfile, newerrorcallback, task.destinationtable, processingtaskid); } if (!errorreported) transaction.complete(); } i'm sure there no transactionscope started ahead or after code. i'm using entity framework insert in db. regardless state of errorreported transaction never rolled in case of error. what missing ? transactionscope sets transaction.current . that's does. wants transacted must @ property. i believe ef each time connection opened reason. probably, connection open when scope installed. open connection inside of scope or enlist manually. ef has nasty "design decision": default opens
Read more