python - Get N maximum values and indices along an axis in a NumPy array -

-

i think easy question experienced numpy users.

i have score matrix. raw index corresponds samples , column index corresponds items. example,

score_matrix =    [[ 1. ,  0.3,  0.4],    [ 0.2,  0.6,  0.8],    [ 0.1,  0.3,  0.5]]

i want top-m indices of items each samples. want top-m scores. example,

top2_ind =    [[0, 2],    [2, 1],    [2, 1]]  top2_score =    [[1. , 0.4],    [0,8, 0.6],    [0.5, 0.3]]

what best way using numpy?

i'd use argsort():

top2_ind = score_matrix.argsort()[:,::-1][:,:2]

that is, produce array contains indices sort score_matrix:

array([[1, 2, 0],        [0, 1, 2],        [0, 1, 2]])

then reverse columns ::-1, take first 2 columns :2:

array([[0, 2],        [2, 1],        [2, 1]])

then similar regular np.sort() values:

top2_score = np.sort(score_matrix)[:,::-1][:,:2]

which following same mechanics above, gives you:

array([[ 1. ,  0.4],        [ 0.8,  0.6],        [ 0.5,  0.3]])

Comments

Post a Comment

Popular posts from this blog

jsf - "PropertyNotWritableException: Illegal Syntax for Set Operation" error when setting value in bean -

-
this question has answer here: how send form input values , invoke method in jsf bean 1 answer i error when trying send values jsf page bean. i want set values fields in bean, create airplane instance , add database. error telling me use illegal syntax setter part of bean. why error? didnt find on site helped me problem. here jsf part: <h4>add plane</h4> <c:if test="#{not empty listairplanebb.error}"> <div class="alert alert-danger"> <span class="glyphicon glyphicon-remove"></span> <h:outputtext value="#{listairplanebb.error}" /> </div> </c:if> <h:form> <table class="table"> <thead> ...
Read more

arrays - Algorithm to find ideal starting spot in a circle -

-
so problem have been debating such: your given array of integers representing circle. then, have pick spot in circle start. place start, compare value @ array number of steps took there , if steps less or equal number, include in final set. find place start have elements in set. ex, a=[0, 1, 2] if start @ index=0, then: a[0]=0 < =0 0 included a[1]=1 < =1 1 included a[2]=2 < =2 2 included final set: {0,1,2} if start @ index=1, then: a[1]=1 > 0 1 not included a[2]=2 > 1 2 not included here loop around a[0]=0 > 2 0 included final set: {0} if start @ index=2, then: a[2]=2 > 0 2 not included, here loop around a[0]=0 < = 1 0 included a[1]=1 < = 2 1 included final set: {0,1} so in trivial case, starting position index=0 best position results in final set elements. brute force method of finding obvious, trying find more efficient method. attempts far have been examine trying find max intersect of viable starting ranges calculated each element in arr...
Read more

php - Autoloader issue not returning Class -

-
problem? bootloader (autoloader) not seem working properly, or i'm missing something. here simplified code. the code below returns class "skeleton" not exist. on index.php file. index.php <?php include 'bootloader.php'; use skeleton\html\loginheader; $tool = new skeleton/html/loginheader(); bootloader.php <?php function boot($classname) { $filename = ''; $namespace = ''; // sets include path "src" directory $includepath = dirname(__file__).directory_separator.'src'; if (false !== ($lastnspos = strripos($classname, '\\'))) { $namespace = substr($classname, 0, $lastnspos); $classname = substr($classname, $lastnspos + 1); $filename = str_replace('\\', directory_separator, $namespace) . directory_separator; } $filename .= str_replace('_', directory_separator, $classname) . '.php'...
Read more