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#include "mp.h"
#include <cassert>
#include <cmath>
#include <algorithm>
#include "utils.h"
static const float EPSILON = 1e-6f;
void mp::neighborhoodPreservation(const arma::mat &distA,
const arma::mat &distB,
arma::uword k,
arma::vec &v)
{
int n = uintToInt<arma::uword, int>(v.n_elem);
#pragma omp parallel for shared(v, n)
for (int i = 0; i < n; i++) {
//arma::uvec nnA(k);
//arma::uvec nnB(k);
//arma::vec dist(k);
//mp::knn(distA, i, k, nnA, dist);
//mp::knn(distB, i, k, nnB, dist);
arma::uvec nnA = arma::sort_index(distA.col(i));
nnA = nnA.subvec(2, k + 1);
arma::uvec nnB = arma::sort_index(distB.col(i));
nnB = nnB.subvec(2, k + 1);
std::sort(nnA.begin(), nnA.end());
std::sort(nnB.begin(), nnB.end());
arma::uword l;
for (l = 0; nnA[l] == nnB[l] && l < k; l++);
v[i] = ((double) l) / k;
}
}
arma::vec mp::silhouette(const arma::mat &distA,
const arma::mat &distB,
const arma::vec &labels)
{
// TODO
return arma::vec(distA.n_rows, arma::fill::zeros);
}
void mp::aggregatedError(const arma::mat &distX,
const arma::mat &distY,
arma::vec &v)
{
int n = uintToInt<arma::uword, int>(v.n_elem);
double maxX = distX.max();
double maxY = distY.max();
#pragma omp parallel for shared(maxX, maxY, distX, distY, v, n)
for (int i = 0; i < n; i++) {
v[i] = 0;
for (int j = 0; j < n; j++) {
if (i == j) {
continue;
}
double diff = fabs(distY(i, j) / maxY - distX(i, j) / maxX);
if (diff < EPSILON) {
continue;
}
v[i] += diff;
}
}
}
/*
double mp::stress(const arma::mat &Dp, const arma::mat &Dq)
{
assert(Dp.n_rows == Dp.n_cols);
assert(Dq.n_rows == Dq.n_cols);
assert(Dp.n_rows == Dq.n_rows);
arma::uword n = Dp.n_rows;
double sigma = 0, s = 0;
for (arma::uword i = 0; i < n; i++)
for (arma::uword j = i + 1; j < n; j++) {
double delta = Dp(i, j);
double d = Dq(i, j);
sigma += (delta - d) * (delta - d) / delta;
s += delta;
}
return sigma / s;
}
arma::vec mp::klDivergence(const arma::mat &P, const arma::mat &Q)
{
arma::vec diver(P.n_rows);
mp::klDivergence(P, Q, diver);
return diver;
}
void mp::klDivergence(const arma::mat &P, const arma::mat &Q, arma::vec &diverg)
{
assert(P.n_rows == P.n_cols);
assert(Q.n_rows == Q.n_cols);
assert(P.n_rows == Q.n_cols);
assert(diverg.n_elem == P.n_rows);
arma::uword n = P.n_rows;
for (arma::uword i = 0; i < n; i++)
diverg(i) = klDivergence(P.row(i), Q.row(i));
}
double mp::klDivergence(const arma::rowvec &pi, const arma::rowvec &qi)
{
// Pii and Qii should both be 1, zeroing the i-th term in the sum below
return arma::accu(pi % arma::log(pi / qi));
}
arma::mat mp::d2p(const arma::mat &D, const arma::vec &sigmas)
{
arma::mat P(D.n_rows, D.n_cols);
mp::d2p(D, sigmas, P);
return P;
}
void mp::d2p(const arma::mat &D, const arma::vec &sigmas, arma::mat &P)
{
// WARNING: assumes D and sigmas are already squared
assert(D.n_rows == D.n_cols);
assert(P.n_rows == P.n_cols);
assert(D.n_rows == P.n_rows);
arma::uword n = D.n_rows;
for (arma::uword i = 0; i < n; i++) {
double den = -1; // k == i must be skipped
for (arma::uword k = 0; k < n; k++)
den += exp(-D(i, k) / sigmas(i));
for (arma::uword j = 0; j < n; j++)
P(i, j) = exp(-D(i, j) / sigmas(i)) / den;
}
}
*/
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