Add SPnDE n=2

This commit is contained in:
2025-03-13 10:58:43 +01:00
parent 4ded6f51eb
commit c234308701
7 changed files with 775 additions and 16 deletions

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@@ -35,4 +35,4 @@ namespace bayesnet {
return model.graph(name);
}
}
}

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@@ -0,0 +1,575 @@
// ***************************************************************
// SPDX-FileCopyrightText: Copyright 2024 Ricardo Montañana Gómez
// SPDX-FileType: SOURCE
// SPDX-License-Identifier: MIT
// ***************************************************************
#include "XSPnDE.h"
#include <pthread.h> // for pthread_setname_np on linux
#include <cassert>
#include <cmath>
#include <limits>
#include <stdexcept>
#include <iostream>
#include "bayesnet/utils/TensorUtils.h"
namespace bayesnet {
// --------------------------------------
// Constructor
// --------------------------------------
XSpnde::XSpnde(int spIndex1, int spIndex2)
: superParent1_{ spIndex1 }
, superParent2_{ spIndex2 }
, nFeatures_{0}
, statesClass_{0}
, alpha_{1.0}
, initializer_{1.0}
, semaphore_{ CountingSemaphore::getInstance() }
, Classifier(Network())
{
validHyperparameters = { "parent1", "parent2" };
}
// --------------------------------------
// setHyperparameters
// --------------------------------------
void XSpnde::setHyperparameters(const nlohmann::json &hyperparameters_)
{
auto hyperparameters = hyperparameters_;
if (hyperparameters.contains("parent1")) {
superParent1_ = hyperparameters["parent1"];
hyperparameters.erase("parent1");
}
if (hyperparameters.contains("parent2")) {
superParent2_ = hyperparameters["parent2"];
hyperparameters.erase("parent2");
}
// Hand off anything else to base Classifier
Classifier::setHyperparameters(hyperparameters);
}
// --------------------------------------
// fitx
// --------------------------------------
void XSpnde::fitx(torch::Tensor & X, torch::Tensor & y,
torch::Tensor & weights_, const Smoothing_t smoothing)
{
m = X.size(1); // number of samples
n = X.size(0); // number of features
dataset = X;
// Build the dataset in your environment if needed:
buildDataset(y);
// Construct the data structures needed for counting
buildModel(weights_);
// Accumulate counts & convert to probabilities
trainModel(weights_, smoothing);
fitted = true;
}
// --------------------------------------
// buildModel
// --------------------------------------
void XSpnde::buildModel(const torch::Tensor &weights)
{
nFeatures_ = n;
// Derive the number of states for each feature from the dataset
// states_[f] = max value in dataset[f] + 1.
states_.resize(nFeatures_);
for (int f = 0; f < nFeatures_; f++) {
// This is naive: we take max in feature f. You might adapt for real data.
states_[f] = dataset[f].max().item<int>() + 1;
}
// Class states:
statesClass_ = dataset[-1].max().item<int>() + 1;
// Initialize the class counts
classCounts_.resize(statesClass_, 0.0);
// For sp1 -> p(sp1Val| c)
sp1FeatureCounts_.resize(states_[superParent1_] * statesClass_, 0.0);
// For sp2 -> p(sp2Val| c)
sp2FeatureCounts_.resize(states_[superParent2_] * statesClass_, 0.0);
// For child features, we store p(childVal | c, sp1Val, sp2Val).
// childCounts_ will hold raw counts. Well gather them in one big vector.
// We need an offset for each feature.
childOffsets_.resize(nFeatures_, -1);
int totalSize = 0;
for (int f = 0; f < nFeatures_; f++) {
if (f == superParent1_ || f == superParent2_) {
// skip the superparents
childOffsets_[f] = -1;
continue;
}
childOffsets_[f] = totalSize;
// block size for a single child f: states_[f] * statesClass_
// * states_[superParent1_]
// * states_[superParent2_].
totalSize += (states_[f] * statesClass_
* states_[superParent1_]
* states_[superParent2_]);
}
childCounts_.resize(totalSize, 0.0);
}
// --------------------------------------
// trainModel
// --------------------------------------
void XSpnde::trainModel(const torch::Tensor &weights,
const bayesnet::Smoothing_t smoothing)
{
// Accumulate raw counts
for (int i = 0; i < m; i++) {
std::vector<int> instance(nFeatures_ + 1);
for (int f = 0; f < nFeatures_; f++) {
instance[f] = dataset[f][i].item<int>();
}
instance[nFeatures_] = dataset[-1][i].item<int>(); // class
double w = weights[i].item<double>();
addSample(instance, w);
}
// Choose alpha based on smoothing:
switch (smoothing) {
case bayesnet::Smoothing_t::ORIGINAL:
alpha_ = 1.0 / m;
break;
case bayesnet::Smoothing_t::LAPLACE:
alpha_ = 1.0;
break;
default:
alpha_ = 0.0; // no smoothing
}
// Large initializer factor for numerical stability
initializer_ = std::numeric_limits<double>::max() / (nFeatures_ * nFeatures_);
// Convert raw counts to probabilities
computeProbabilities();
}
// --------------------------------------
// addSample
// --------------------------------------
void XSpnde::addSample(const std::vector<int> &instance, double weight)
{
if (weight <= 0.0)
return;
int c = instance.back();
// increment classCounts
classCounts_[c] += weight;
int sp1Val = instance[superParent1_];
int sp2Val = instance[superParent2_];
// p(sp1|c)
sp1FeatureCounts_[sp1Val * statesClass_ + c] += weight;
// p(sp2|c)
sp2FeatureCounts_[sp2Val * statesClass_ + c] += weight;
// p(childVal| c, sp1Val, sp2Val)
for (int f = 0; f < nFeatures_; f++) {
if (f == superParent1_ || f == superParent2_)
continue;
int childVal = instance[f];
int offset = childOffsets_[f];
// block layout:
// offset + (sp1Val*(states_[sp2_]* states_[f]* statesClass_))
// + (sp2Val*(states_[f]* statesClass_))
// + childVal*(statesClass_)
// + c
int blockSizeSp2 = states_[superParent2_]
* states_[f]
* statesClass_;
int blockSizeChild = states_[f] * statesClass_;
int idx = offset
+ sp1Val*blockSizeSp2
+ sp2Val*blockSizeChild
+ childVal*statesClass_
+ c;
childCounts_[idx] += weight;
}
}
// --------------------------------------
// computeProbabilities
// --------------------------------------
void XSpnde::computeProbabilities()
{
double totalCount = std::accumulate(classCounts_.begin(),
classCounts_.end(), 0.0);
// classPriors_
classPriors_.resize(statesClass_, 0.0);
if (totalCount <= 0.0) {
// fallback => uniform
double unif = 1.0 / static_cast<double>(statesClass_);
for (int c = 0; c < statesClass_; c++) {
classPriors_[c] = unif;
}
} else {
for (int c = 0; c < statesClass_; c++) {
classPriors_[c] =
(classCounts_[c] + alpha_)
/ (totalCount + alpha_ * statesClass_);
}
}
// p(sp1Val| c)
sp1FeatureProbs_.resize(sp1FeatureCounts_.size());
int sp1Card = states_[superParent1_];
for (int spVal = 0; spVal < sp1Card; spVal++) {
for (int c = 0; c < statesClass_; c++) {
double denom = classCounts_[c] + alpha_ * sp1Card;
double num = sp1FeatureCounts_[spVal * statesClass_ + c] + alpha_;
sp1FeatureProbs_[spVal * statesClass_ + c] =
(denom <= 0.0 ? 0.0 : num / denom);
}
}
// p(sp2Val| c)
sp2FeatureProbs_.resize(sp2FeatureCounts_.size());
int sp2Card = states_[superParent2_];
for (int spVal = 0; spVal < sp2Card; spVal++) {
for (int c = 0; c < statesClass_; c++) {
double denom = classCounts_[c] + alpha_ * sp2Card;
double num = sp2FeatureCounts_[spVal * statesClass_ + c] + alpha_;
sp2FeatureProbs_[spVal * statesClass_ + c] =
(denom <= 0.0 ? 0.0 : num / denom);
}
}
// p(childVal| c, sp1Val, sp2Val)
childProbs_.resize(childCounts_.size());
int offset = 0;
for (int f = 0; f < nFeatures_; f++) {
if (f == superParent1_ || f == superParent2_)
continue;
int fCard = states_[f];
int sp1Card_ = states_[superParent1_];
int sp2Card_ = states_[superParent2_];
int childBlockSizeSp2 = sp2Card_ * fCard * statesClass_;
int childBlockSizeF = fCard * statesClass_;
int blockSize = fCard * sp1Card_ * sp2Card_ * statesClass_;
for (int sp1Val = 0; sp1Val < sp1Card_; sp1Val++) {
for (int sp2Val = 0; sp2Val < sp2Card_; sp2Val++) {
for (int childVal = 0; childVal < fCard; childVal++) {
for (int c = 0; c < statesClass_; c++) {
// index in childCounts_
int idx = offset
+ sp1Val*childBlockSizeSp2
+ sp2Val*childBlockSizeF
+ childVal*statesClass_
+ c;
double num = childCounts_[idx] + alpha_;
// denominator is the count of (sp1Val,sp2Val,c) plus alpha * fCard
// We can find that by summing childVal dimension, but we already
// have it in childCounts_[...] or we can re-check the superparent
// counts if your approach is purely hierarchical.
// Here we'll do it like the XSpode approach: sp1&sp2 are
// conditionally independent given c, so denominators come from
// summing the relevant block or we treat sp1,sp2 as "parents."
// A simpler approach:
double sumSp1Sp2C = 0.0;
// sum over all childVal:
for (int cv = 0; cv < fCard; cv++) {
int idx2 = offset
+ sp1Val*childBlockSizeSp2
+ sp2Val*childBlockSizeF
+ cv*statesClass_ + c;
sumSp1Sp2C += childCounts_[idx2];
}
double denom = sumSp1Sp2C + alpha_ * fCard;
childProbs_[idx] = (denom <= 0.0 ? 0.0 : num / denom);
}
}
}
}
offset += blockSize;
}
}
// --------------------------------------
// predict_proba (single instance)
// --------------------------------------
std::vector<double> XSpnde::predict_proba(const std::vector<int> &instance) const
{
if (!fitted) {
throw std::logic_error(CLASSIFIER_NOT_FITTED);
}
std::vector<double> probs(statesClass_, 0.0);
int sp1Val = instance[superParent1_];
int sp2Val = instance[superParent2_];
// Start with p(c) * p(sp1Val| c) * p(sp2Val| c)
for (int c = 0; c < statesClass_; c++) {
double pC = classPriors_[c];
double pSp1C = sp1FeatureProbs_[sp1Val * statesClass_ + c];
double pSp2C = sp2FeatureProbs_[sp2Val * statesClass_ + c];
probs[c] = pC * pSp1C * pSp2C * initializer_;
}
// Multiply by each child feature f
int offset = 0;
for (int f = 0; f < nFeatures_; f++) {
if (f == superParent1_ || f == superParent2_)
continue;
int valF = instance[f];
int fCard = states_[f];
int sp1Card = states_[superParent1_];
int sp2Card = states_[superParent2_];
int blockSizeSp2 = sp2Card * fCard * statesClass_;
int blockSizeF = fCard * statesClass_;
// base index for childProbs_ for this child and sp1Val, sp2Val
int base = offset
+ sp1Val*blockSizeSp2
+ sp2Val*blockSizeF
+ valF*statesClass_;
for (int c = 0; c < statesClass_; c++) {
probs[c] *= childProbs_[base + c];
}
offset += (fCard * sp1Card * sp2Card * statesClass_);
}
// Normalize
normalize(probs);
return probs;
}
// --------------------------------------
// predict_proba (batch)
// --------------------------------------
std::vector<std::vector<double>> XSpnde::predict_proba(std::vector<std::vector<int>> &test_data)
{
int test_size = test_data[0].size(); // each feature is test_data[f], size = #samples
int sample_size = test_data.size(); // = nFeatures_
std::vector<std::vector<double>> probabilities(
test_size, std::vector<double>(statesClass_, 0.0));
// same concurrency approach
int chunk_size = std::min(150, int(test_size / semaphore_.getMaxCount()) + 1);
std::vector<std::thread> threads;
auto worker = [&](const std::vector<std::vector<int>> &samples,
int begin,
int chunk,
int sample_size,
std::vector<std::vector<double>> &predictions) {
std::string threadName =
"XSpnde-" + std::to_string(begin) + "-" + std::to_string(chunk);
#if defined(__linux__)
pthread_setname_np(pthread_self(), threadName.c_str());
#else
pthread_setname_np(threadName.c_str());
#endif
std::vector<int> instance(sample_size);
for (int sample = begin; sample < begin + chunk; ++sample) {
for (int feature = 0; feature < sample_size; ++feature) {
instance[feature] = samples[feature][sample];
}
predictions[sample] = predict_proba(instance);
}
semaphore_.release();
};
for (int begin = 0; begin < test_size; begin += chunk_size) {
int chunk = std::min(chunk_size, test_size - begin);
semaphore_.acquire();
threads.emplace_back(worker, test_data, begin, chunk, sample_size,
std::ref(probabilities));
}
for (auto &th : threads) {
th.join();
}
return probabilities;
}
// --------------------------------------
// predict (single instance)
// --------------------------------------
int XSpnde::predict(const std::vector<int> &instance) const
{
auto p = predict_proba(instance);
return static_cast<int>(
std::distance(p.begin(), std::max_element(p.begin(), p.end()))
);
}
// --------------------------------------
// predict (batch of data)
// --------------------------------------
std::vector<int> XSpnde::predict(std::vector<std::vector<int>> &test_data)
{
auto probabilities = predict_proba(test_data);
std::vector<int> predictions(probabilities.size(), 0);
for (size_t i = 0; i < probabilities.size(); i++) {
predictions[i] = static_cast<int>(
std::distance(probabilities[i].begin(),
std::max_element(probabilities[i].begin(),
probabilities[i].end()))
);
}
return predictions;
}
// --------------------------------------
// predict (torch::Tensor version)
// --------------------------------------
torch::Tensor XSpnde::predict(torch::Tensor &X)
{
auto X_ = TensorUtils::to_matrix(X);
auto result_v = predict(X_);
return torch::tensor(result_v, torch::kInt32);
}
// --------------------------------------
// predict_proba (torch::Tensor version)
// --------------------------------------
torch::Tensor XSpnde::predict_proba(torch::Tensor &X)
{
auto X_ = TensorUtils::to_matrix(X);
auto result_v = predict_proba(X_);
int n_samples = X.size(1);
torch::Tensor result =
torch::zeros({ n_samples, statesClass_ }, torch::kDouble);
for (int i = 0; i < (int)result_v.size(); ++i) {
result.index_put_({ i, "..." }, torch::tensor(result_v[i]));
}
return result;
}
// --------------------------------------
// score (torch::Tensor version)
// --------------------------------------
float XSpnde::score(torch::Tensor &X, torch::Tensor &y)
{
torch::Tensor y_pred = predict(X);
return (y_pred == y).sum().item<float>() / y.size(0);
}
// --------------------------------------
// score (vector version)
// --------------------------------------
float XSpnde::score(std::vector<std::vector<int>> &X, std::vector<int> &y)
{
auto y_pred = predict(X);
int correct = 0;
for (size_t i = 0; i < y_pred.size(); ++i) {
if (y_pred[i] == y[i]) {
correct++;
}
}
return static_cast<float>(correct) / static_cast<float>(y_pred.size());
}
// --------------------------------------
// Utility: normalize
// --------------------------------------
void XSpnde::normalize(std::vector<double> &v) const
{
double sum = 0.0;
for (auto &val : v) {
sum += val;
}
if (sum > 0.0) {
for (auto &val : v) {
val /= sum;
}
}
}
// --------------------------------------
// to_string
// --------------------------------------
std::string XSpnde::to_string() const
{
std::ostringstream oss;
oss << "----- XSpnde Model -----\n"
<< "nFeatures_ = " << nFeatures_ << "\n"
<< "superParent1_ = " << superParent1_ << "\n"
<< "superParent2_ = " << superParent2_ << "\n"
<< "statesClass_ = " << statesClass_ << "\n\n";
oss << "States: [";
for (auto s : states_) oss << s << " ";
oss << "]\n";
oss << "classCounts_:\n";
for (auto v : classCounts_) oss << v << " ";
oss << "\nclassPriors_:\n";
for (auto v : classPriors_) oss << v << " ";
oss << "\nsp1FeatureCounts_ (size=" << sp1FeatureCounts_.size() << ")\n";
for (auto v : sp1FeatureCounts_) oss << v << " ";
oss << "\nsp2FeatureCounts_ (size=" << sp2FeatureCounts_.size() << ")\n";
for (auto v : sp2FeatureCounts_) oss << v << " ";
oss << "\nchildCounts_ (size=" << childCounts_.size() << ")\n";
for (auto v : childCounts_) oss << v << " ";
oss << "\nchildOffsets_:\n";
for (auto c : childOffsets_) oss << c << " ";
oss << "\n----------------------------------------\n";
return oss.str();
}
// --------------------------------------
// Some introspection about the graph
// --------------------------------------
int XSpnde::getNumberOfNodes() const
{
// nFeatures + 1 class node
return nFeatures_ + 1;
}
int XSpnde::getClassNumStates() const
{
return statesClass_;
}
int XSpnde::getNFeatures() const
{
return nFeatures_;
}
int XSpnde::getNumberOfStates() const
{
// purely an example. Possibly you want to sum up actual
// cardinalities or something else.
return std::accumulate(states_.begin(), states_.end(), 0) * nFeatures_;
}
int XSpnde::getNumberOfEdges() const
{
// In an SPNDE with n=2, for each feature we have edges from class, sp1, sp2.
// So thats 3*(nFeatures_) edges, minus the ones for the superparents themselves,
// plus the edges from class->superparent1, class->superparent2.
// For a quick approximation:
// - class->sp1, class->sp2 => 2 edges
// - class->child => (nFeatures -2) edges
// - sp1->child, sp2->child => 2*(nFeatures -2) edges
// total = 2 + (nFeatures-2) + 2*(nFeatures-2) = 2 + 3*(nFeatures-2)
// = 3nFeatures - 4 (just an example).
// You can adapt to your liking:
return 3 * nFeatures_ - 4;
}
} // namespace bayesnet

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@@ -0,0 +1,75 @@
// ***************************************************************
// SPDX-FileCopyrightText: Copyright 2024 Ricardo Montañana Gómez
// SPDX-FileType: SOURCE
// SPDX-License-Identifier: MIT
// ***************************************************************
#ifndef XSPNDE_H
#define XSPNDE_H
#include "Classifier.h"
#include "bayesnet/utils/CountingSemaphore.h"
#include <torch/torch.h>
#include <vector>
namespace bayesnet {
class XSpnde : public Classifier {
public:
XSpnde(int spIndex1, int spIndex2);
void setHyperparameters(const nlohmann::json &hyperparameters_) override;
void fitx(torch::Tensor &X, torch::Tensor &y, torch::Tensor &weights_, const Smoothing_t smoothing);
std::vector<double> predict_proba(const std::vector<int> &instance) const;
std::vector<std::vector<double>> predict_proba(std::vector<std::vector<int>> &test_data) override;
int predict(const std::vector<int> &instance) const;
std::vector<int> predict(std::vector<std::vector<int>> &test_data) override;
torch::Tensor predict(torch::Tensor &X) override;
torch::Tensor predict_proba(torch::Tensor &X) override;
float score(torch::Tensor &X, torch::Tensor &y) override;
float score(std::vector<std::vector<int>> &X, std::vector<int> &y) override;
std::string to_string() const;
std::vector<std::string> graph(const std::string &title) const override {
return std::vector<std::string>({title});
}
int getNumberOfNodes() const override;
int getNumberOfEdges() const override;
int getNFeatures() const;
int getClassNumStates() const override;
int getNumberOfStates() const override;
protected:
void buildModel(const torch::Tensor &weights) override;
void trainModel(const torch::Tensor &weights, const bayesnet::Smoothing_t smoothing) override;
private:
void addSample(const std::vector<int> &instance, double weight);
void normalize(std::vector<double> &v) const;
void computeProbabilities();
int superParent1_;
int superParent2_;
int nFeatures_;
int statesClass_;
double alpha_;
double initializer_;
std::vector<int> states_;
std::vector<double> classCounts_;
std::vector<double> classPriors_;
std::vector<double> sp1FeatureCounts_, sp1FeatureProbs_;
std::vector<double> sp2FeatureCounts_, sp2FeatureProbs_;
// childOffsets_[f] will be the offset into childCounts_ for feature f.
// If f is either superParent1 or superParent2, childOffsets_[f] = -1
std::vector<int> childOffsets_;
// For each child f, we store p(x_f | c, sp1Val, sp2Val). We'll store the raw
// counts in childCounts_, and the probabilities in childProbs_, with a
// dimension block of size: states_[f]* statesClass_* states_[sp1]* states_[sp2].
std::vector<double> childCounts_;
std::vector<double> childProbs_;
CountingSemaphore &semaphore_;
};
} // namespace bayesnet
#endif // XSPNDE_H