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Density Z-Score

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randogoth 2024-03-01 15:46:52 +02:00
parent 158d0c1bfe
commit 9c3220fd14
1 changed files with 25 additions and 27 deletions
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52
src/main.rs
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@ -127,38 +127,36 @@ fn calculate_densities_and_gaps(dataset: &[Point], factor: f32, min_cluster_size
///
fn lyagushka(dataset: Vec<Point>, factor: f32, min_cluster_size: usize) -> String {
// Analyze the dataset to identify clusters and significant gaps.
// Calculate clusters and gaps from the dataset using predefined criteria.
let mut cluster_gap_infos = calculate_densities_and_gaps(&dataset, factor, min_cluster_size);
// Calculate the mean distance between consecutive points in the dataset.
let mean_distance: f32 = if dataset.len() > 1 {
dataset.windows(2)
.map(|w| w[1].value as f32 - w[0].value as f32)
.sum::<f32>() / (dataset.len() - 1) as f32
} else {
0.0
};
// Calculate the mean density of clusters in the dataset for comparison.
let mean_density: f32 = cluster_gap_infos.iter()
.filter(|info| info.num_elements > 0)
.map(|info| info.num_elements as f32 / info.span_length)
.sum::<f32>() / cluster_gap_infos.iter().filter(|info| info.num_elements > 0).count() as f32;
// Calculate the standard deviation of distances between consecutive points.
let std_deviation: f32 = if dataset.len() > 1 {
(dataset.windows(2)
.map(|w| w[1].value as f32 - w[0].value as f32 - mean_distance)
.map(|d| d.powi(2))
.sum::<f32>() / (dataset.len() - 1) as f32)
.sqrt()
} else {
0.0
};
// Calculate the standard deviation of cluster densities to evaluate variation.
let variance_density: f32 = cluster_gap_infos.iter()
.filter(|info| info.num_elements > 0)
.map(|info| info.num_elements as f32 / info.span_length)
.map(|density| (density - mean_density).powi(2))
.sum::<f32>() / cluster_gap_infos.iter().filter(|info| info.num_elements > 0).count() as f32;
let std_dev_density = variance_density.sqrt();
// Calculate and assign z-scores for each cluster/gap based on their centroid or span length.
for info in cluster_gap_infos.iter_mut() {
info.z_score = Some(if info.num_elements > 0 {
// For clusters, use the centroid for z-score calculation.
(info.centroid - mean_distance) / std_deviation
// Calculate the average span of all clusters and gaps to assess gap significance.
let average_span: f32 = cluster_gap_infos.iter().map(|info| info.span_length).sum::<f32>() / cluster_gap_infos.len() as f32;
// Update Z-scores for both clusters and gaps based on their deviation from mean metrics.
for info in &mut cluster_gap_infos {
if info.num_elements > 0 {
// Calculate and update Z-score for clusters based on density deviation.
let cluster_density = info.num_elements as f32 / info.span_length;
info.z_score = Some((cluster_density - mean_density) / std_dev_density);
} else {
// For gaps, use the span length for z-score calculation.
(info.span_length - mean_distance) / std_deviation
});
// Calculate and update Z-score for gaps based on span length deviation.
info.z_score = Some((info.span_length - average_span) / std_dev_density);
}
}
serde_json::to_string_pretty(&cluster_gap_infos).unwrap_or_else(|_| "Failed to serialize data".to_string())