Learning a binary classifier which outputs probability -

-

when, in general, objective build binary classifier outputs probability instance positive, machine learning appropriate , in situation?

in particular, seems support vector machines platt's scaling candidate, read around web uses kernel logistic regression or gaussian processes task. there evident advantage/disadvantage of 1 approach against others?

thank you

listing potential algorithms use general task close impossible. since mentioned support vector machines (svms), try elaborate little on those.

svm classifiers never output actual probability. output of svm classifier distance of test instance separating hyperplane in feature space (this called decision value). default, predicted label selected based on sign of decision value.

platt scaling fits sigmoid on top of svm decision values scale range of [0, 1], can interpreted probability. similar techniques can applied on type of classifier produces real-valued output.

some evident advantages svm include:

  • computationally efficient nonlinear classifiers (quadratic in no. of training instances),
  • can deal high-dimensional data,
  • have shown performance in countless domains.

downsides svm include:

  • data must vectorized,
  • models relatively hard interpret (compared decision trees or logistic regression),
  • dealing nominal features can klunky,
  • missing values can hard deal with.

when looking proper probabilistic outputs (including confidence intervals), may want consider statistical methods such logistic regression (kernelized versions exist too, suggest start basic stuff).


Comments

Post a Comment

Popular posts from this blog

Perl - how to grep a block of text from a file -

-
it can in xml or text format. how in general grep block of text in perl? <track type="ws"> <range> <rangestart>0</rangestart> <rangeend>146.912</rangeend> <locationindex>0</locationindex> <propertyindex>0</propertyindex> </range> </track> <track type="ps" id="1"> <range> <rangestart>0</rangestart> <rangeend>146.912</rangeend> <locationindex>1</locationindex> <propertyindex>1</propertyindex> </range> </track> i want grep type="ps" , till </range> . one solution open file, read line line , match block. open(fh, "file.txt"); foreach $line (<fh>) { if ($line =~ m/type="cc"(.*?)<\/range>/) { print $1; } } but there more optimal solution without reading file line l
Read more

delphi - How to remove all the grips on a coolbar if I have several coolbands? -

-
Image
if set mycoolbar.fixedorder true,only grip on first band hidden. well,if use delphi 7 create vcl forms application,then put coolbar on , create 3 coolbans hold other controls,only grip , top coolbands can hidden setting mycoolbar.fixedorder:=true. i've uploaded picture make things clear. you got fixedorder property wrong. fixed property not allow bands rearranged if set true . setting property of coolbar true keep user changing bands order @ runtime, user can still move , resize bands. can give advice can do, actual solution problem, well, have wait answer. my advice use 3 coolbars in row , setting "fixedorder" property true , bandborderstyle bsnone . way grip hidden on of them. about property, it's not bug of ide, actual preference of property.
Read more

javascript - Animating array of divs; only the final element is modified -

-
this baffling me @ moment. i'm experienced programmer looking throw bit of surprise fiancee on countdown page our wedding. desired effect simulated confetti falling behind main page. setup follows: i have array of divs in javascript. each div absolutely positioned on page. have interval set updates every 50 or milliseconds. on each tick, run loop on array of divs, , calculations , update positions. problem problem having, however, though can see divs created, stored array, , modified (in case, each has slight randomized rotation) during initialization phase, once tick update position starts, div stored in whatever last slot of array gets position updated. tried hard-coding each div index testing purposes, strictly last element update position. upon printing current "left" , "top" style values each div before , after calculations shows value has been changed, no visible change noticeable. here's basic code: javascript var container;
Read more