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Add same_values to getCandidate and fine tune ValueCutPoint

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This commit is contained in:
Ricardo Montañana Gómez
2023-02-15 13:07:03 +01:00
parent e37702dcb0
commit 04c1772019
1 changed files with 60 additions and 66 deletions
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126
CPPFImdlp.cpp
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@@ -4,43 +4,26 @@
#include <cmath>
#include "CPPFImdlp.h"
#include "Metrics.h"
#include <iostream>
namespace mdlp {
CPPFImdlp::CPPFImdlp(int algorithm):algorithm(algorithm), indices(indices_t()), X(samples_t()), y(labels_t()), metrics(Metrics(y, indices))
{
CPPFImdlp::CPPFImdlp(int algorithm) : algorithm(algorithm), indices(indices_t()), X(samples_t()), y(labels_t()),
metrics(Metrics(y, indices)) {
}
CPPFImdlp::~CPPFImdlp()
= default;
CPPFImdlp& CPPFImdlp::fit(samples_t& X_, labels_t& y_)
{
CPPFImdlp::~CPPFImdlp() = default;
CPPFImdlp &CPPFImdlp::fit(samples_t &X_, labels_t &y_) {
X = X_;
y = y_;
cutPoints.clear();
if (X.size() != y.size()) {
throw invalid_argument("X and y must have the same size");
}
if (X.size() == 0 || y.size() == 0) {
if (X.empty() || y.empty()) {
throw invalid_argument("X and y must have at least one element");
}
indices = sortIndices(X_, y_);
metrics.setData(y, indices);
for (auto i=0; i< X.size(); i++) {
if (i% 10 ==0) {
cout << " # Idx --X-- y"<<endl;
cout << "--- --- ----- -"<<endl;
}
auto index = indices[i];
cout.width(3);
cout << i << " ";
cout.width(3);
cout << index << " ";
cout.width(5);
cout << X[index];
cout.width(1);
cout << " " << y[index] << endl;
}
switch (algorithm) {
case 0:
computeCutPoints(0, X.size());
@@ -58,8 +41,8 @@ namespace mdlp {
}
return *this;
}
precision_t CPPFImdlp::halfWayValueCutPoint(size_t start, size_t idx)
{
precision_t CPPFImdlp::halfWayValueCutPoint(size_t start, size_t idx) {
size_t idxPrev = idx - 1;
precision_t previous = X[indices[idxPrev]], actual = X[indices[idx]];
// definition 2 of the paper => X[t-1] < X[t]
@@ -68,9 +51,10 @@ namespace mdlp {
}
return (previous + actual) / 2;
}
tuple<precision_t, size_t> CPPFImdlp::completeValueCutPoint(size_t start, size_t cut, size_t end)
{
tuple<precision_t, size_t> CPPFImdlp::completeValueCutPoint(size_t start, size_t cut, size_t end) {
size_t idxPrev = cut - 1;
bool fforward = false;
precision_t previous, actual;
previous = X[indices[idxPrev]];
actual = X[indices[cut]];
@@ -79,14 +63,19 @@ namespace mdlp {
previous = X[indices[idxPrev]];
}
// get the last equal value of X in the interval
while (actual == X[indices[++cut]] && cut < end);
if (previous == actual && cut < end)
actual = X[indices[cut]];
cut--;
while (actual == X[indices[cut]] && cut + 1 < end) {
cut++;
fforward = true;
}
if (fforward)
cut--;
// try to get the next value if it can't be found backwards
if (previous == actual && cut + 1 < end)
actual = X[indices[cut + 1]];
return make_tuple((previous + actual) / 2, cut);
}
void CPPFImdlp::computeCutPoints(size_t start, size_t end)
{
void CPPFImdlp::computeCutPoints(size_t start, size_t end) {
size_t cut;
tuple<precision_t, size_t> result;
if (end - start < 2)
@@ -102,8 +91,8 @@ namespace mdlp {
computeCutPoints(cut, end);
}
}
void CPPFImdlp::computeCutPointsAlternative(size_t start, size_t end)
{
void CPPFImdlp::computeCutPointsAlternative(size_t start, size_t end) {
size_t cut;
if (end - start < 2)
return;
@@ -116,8 +105,8 @@ namespace mdlp {
computeCutPointsAlternative(cut, end);
}
}
void CPPFImdlp::computeCutPointsClassic(size_t start, size_t end)
{
void CPPFImdlp::computeCutPointsClassic(size_t start, size_t end) {
size_t cut;
cut = getCandidate(start, end);
if (cut == numeric_limits<size_t>::max() || !mdlp(start, cut, end)) {
@@ -135,14 +124,17 @@ namespace mdlp {
computeCutPoints(start, cut);
computeCutPoints(cut, end);
}
size_t CPPFImdlp::getCandidate(size_t start, size_t end)
{
size_t CPPFImdlp::getCandidate(size_t start, size_t end) {
/* Definition 1: A binary discretization for A is determined by selecting the cut point TA for which
E(A, TA; S) is minimal amogst all the candidate cut points. */
E(A, TA; S) is minimal amongst all the candidate cut points. */
size_t candidate = numeric_limits<size_t>::max(), elements = end - start;
bool same_values = true;
precision_t entropy_left, entropy_right, minEntropy;
minEntropy = metrics.entropy(start, end);
for (auto idx = start + 1; idx < end; idx++) {
if (X[indices[idx]] != X[indices[idx - 1]])
same_values = false;
// Cutpoints are always on boundaries (definition 2)
if (y[indices[idx]] == y[indices[idx - 1]])
continue;
@@ -153,10 +145,13 @@ namespace mdlp {
candidate = idx;
}
}
// If all the values of the variable in the interval are the same, it doesn't consider the cut point
if (same_values)
candidate = numeric_limits<size_t>::max();
return candidate;
}
bool CPPFImdlp::mdlp(size_t start, size_t cut, size_t end)
{
bool CPPFImdlp::mdlp(size_t start, size_t cut, size_t end) {
int k, k1, k2;
precision_t ig, delta;
precision_t ent, ent1, ent2;
@@ -172,38 +167,37 @@ namespace mdlp {
ent2 = metrics.entropy(cut, end);
ig = metrics.informationGain(start, cut, end);
delta = log2(pow(3, precision_t(k)) - 2) -
(precision_t(k) * ent - precision_t(k1) * ent1 - precision_t(k2) * ent2);
(precision_t(k) * ent - precision_t(k1) * ent1 - precision_t(k2) * ent2);
precision_t term = 1 / N * (log2(N - 1) + delta);
return ig > term;
}
// Argsort from https://stackoverflow.com/questions/1577475/c-sorting-and-keeping-track-of-indexes
indices_t CPPFImdlp::sortIndices(samples_t& X_, labels_t& y_)
{
indices_t CPPFImdlp::sortIndices(samples_t &X_, labels_t &y_) {
indices_t idx(X_.size());
iota(idx.begin(), idx.end(), 0);
for (size_t i = 0; i < X_.size(); i++)
stable_sort(idx.begin(), idx.end(), [&X_, &y_](size_t i1, size_t i2)
{
if (X_[i1] == X_[i2]) return y_[i1] < y_[i2];
else
return X_[i1] < X_[i2];
});
return idx;
}
// Argsort from https://stackoverflow.com/questions/1577475/c-sorting-and-keeping-track-of-indexes
indices_t CPPFImdlp::sortIndices1(samples_t& X_)
{
indices_t idx(X_.size());
iota(idx.begin(), idx.end(), 0);
for (size_t i = 0; i < X_.size(); i++)
stable_sort(idx.begin(), idx.end(), [&X_](size_t i1, size_t i2)
{
stable_sort(idx.begin(), idx.end(), [&X_, &y_](size_t i1, size_t i2) {
if (X_[i1] == X_[i2])
return y_[i1] < y_[i2];
else
return X_[i1] < X_[i2];
});
});
return idx;
}
cutPoints_t CPPFImdlp::getCutPoints()
{
// Argsort from https://stackoverflow.com/questions/1577475/c-sorting-and-keeping-track-of-indexes
indices_t CPPFImdlp::sortIndices1(samples_t &X_) {
indices_t idx(X_.size());
iota(idx.begin(), idx.end(), 0);
for (size_t i = 0; i < X_.size(); i++)
stable_sort(idx.begin(), idx.end(), [&X_](size_t i1, size_t i2) {
return X_[i1] < X_[i2];
});
return idx;
}
cutPoints_t CPPFImdlp::getCutPoints() {
// Remove duplicates and sort
cutPoints_t output(cutPoints.size());
set<precision_t> s;