view tests/pointset_test/lshP.m @ 405:ef4792df8f93 api-inversion

invert audioDB::insert / audiodb_insert().

Start off by removing audioDB::insertDatum, and essentially reusing it
as audiodb_insert.  We now ignore the fact that the command-line parsing
code has "helpfully" opened a std::ifstream for the times file and an fd
for the power file, and simply go ahead and do our own dirty work.

We can delete audioDB::insertDatum entirely, but unfortunately we can't
delete audioDB::insertPowerData and audioDB::insertTimestamps, because
the index and query code respectively use them.  Instead, move the two
methods closer to their single uses.

audiodb_insert() is perhaps not as short and simple as it might have
been hoped given the existence of audiodb_insert_datum(); some of that
is C and its terribly way of making you pay every time you use dynamic
memory; some of it is the fact that the three different files (feature,
times, power) each requires slightly different treatment.  Hey ho.

We can implement audiodb_batchinsert() in terms of audiodb_insert(); the
function is pleasingly small.  We can't quite use it for
audioDB::batchinsert yet, as we have to deal with the O2_FLAG_LARGE_ADB
case (which codepath is untested in libtests/).

This means that we can delete whole swathes of hideous code from
audioDB.cpp, including not just the versions of audiodb_insert() and
audiodb_batchinsert() but also an entire audioDB constructor.  Yay.
(audioDB::unitNormAndInsertL2 has also died a deserved death).

function P2 = lshP(w,c,k)
if nargin<3, k=1;end
if nargin<2, c=1;end
if nargin<1, w=4;end

P2 = 1 - 2*normcdf(-w./c) - 2./(sqrt(2*pi)*(w./c)) .* ( 1-exp(-w.^2./(2*c.^2)) );
if(k~=1)
  P2 = P2.^k;
endif
endfunction