fix(train,nn): Tier-2 correctness/security — metric scale, OOM bounds, panics (ADR-155 §Tier-2)

Each fix ships a test that would have caught the bug:
- ruview_metrics OKS: derive scale from GT extent (no s=1.0 fake-Gold), reject
  s<=0, bound the loop to array extents (no panic on short/adversarial input).
- config.validate(): UPPER bounds on window_frames/subcarriers/backbone_channels/
  heatmap_size/keypoints/body_parts/batch_size + reject negative gpu_device_id
  (closes the config-OOM class); defaults+presets still validate.
- subcarrier.rs: graceful fallback instead of panic on non-contiguous input.
- ablation.rs latency_percentiles: total_cmp + NaN guard (no partial_cmp unwrap).
- tensor.rs softmax(axis): normalize per-lane along the given axis (was whole-
  tensor), out-of-range axis -> NnError; fixes densepose per-pixel probs.
- translator.rs apply_attention: real scaled-dot-product attention (was a
  uniform 1/seq_len stub that made any "with attention" ablation == without);
  mis-shaped checkpoint projections rejected.

Co-Authored-By: claude-flow <ruv@ruv.net>
This commit is contained in:
ruv
2026-06-11 19:57:32 -04:00
parent 84e2c920fd
commit aa3a6725a6
6 changed files with 651 additions and 36 deletions
+121 -7
View File
@@ -4,11 +4,39 @@
//! different backends (ONNX, tch, Candle).
use crate::error::{NnError, NnResult};
use ndarray::{Array1, Array2, Array3, Array4, ArrayD};
use ndarray::{Array1, Array2, Array3, Array4, ArrayD, ArrayViewMutD, Axis};
// num_traits is available if needed for advanced tensor operations
use serde::{Deserialize, Serialize};
use std::fmt;
/// Apply a numerically-stable softmax in place to every 1-D lane of `view`
/// taken along `axis`. Each lane is shifted by its own max before
/// exponentiation, then divided by its own sum, so every lane sums to 1.0
/// independently — the per-pixel / per-class normalization densepose needs.
///
/// `axis` MUST be validated as in-range by the caller.
fn softmax_inplace_along_axis(mut view: ArrayViewMutD<'_, f32>, axis: usize) {
for mut lane in view.lanes_mut(Axis(axis)) {
let max = lane.iter().copied().fold(f32::NEG_INFINITY, f32::max);
// An all-`-inf` (or empty) lane has no finite max; leave it untouched
// to avoid producing NaNs from `exp(-inf - -inf)`.
if !max.is_finite() {
continue;
}
let mut sum = 0.0f32;
for v in lane.iter_mut() {
let e = (*v - max).exp();
*v = e;
sum += e;
}
if sum > 0.0 {
for v in lane.iter_mut() {
*v /= sum;
}
}
}
}
/// Shape of a tensor
#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub struct TensorShape(Vec<usize>);
@@ -288,14 +316,39 @@ impl Tensor {
}
}
/// Apply softmax along axis
pub fn softmax(&self, _axis: usize) -> NnResult<Tensor> {
/// Apply softmax along the given `axis`.
///
/// Each 1-D lane along `axis` is normalized independently so it sums to
/// 1.0. This is the correct semantics for per-pixel / per-class probability
/// maps (e.g. DensePose body-part logits over the channel axis). A
/// numerically-stable max-shift is applied per lane.
///
/// # Errors
/// Returns [`NnError`] if `axis` is out of range for the tensor's rank, or
/// if the tensor type is unsupported.
pub fn softmax(&self, axis: usize) -> NnResult<Tensor> {
match self {
Tensor::Float4D(a) => {
let max = a.fold(f32::NEG_INFINITY, |acc, &x| acc.max(x));
let exp = a.mapv(|x| (x - max).exp());
let sum = exp.sum();
Ok(Tensor::Float4D(exp / sum))
if axis >= a.ndim() {
return Err(NnError::tensor_op(format!(
"softmax axis {axis} out of range for {}-D tensor",
a.ndim()
)));
}
let mut out = a.clone();
softmax_inplace_along_axis(out.view_mut().into_dyn(), axis);
Ok(Tensor::Float4D(out))
}
Tensor::FloatND(a) => {
if axis >= a.ndim() {
return Err(NnError::tensor_op(format!(
"softmax axis {axis} out of range for {}-D tensor",
a.ndim()
)));
}
let mut out = a.clone();
softmax_inplace_along_axis(out.view_mut(), axis);
Ok(Tensor::FloatND(out))
}
_ => Err(NnError::tensor_op(
"Softmax not supported for this tensor type",
@@ -517,6 +570,67 @@ mod tests {
assert!(sigmoid.max().unwrap() < 1.0);
}
// ADR-155 §Tier-2: softmax(axis) must normalize along the GIVEN axis
// (per-lane sum == 1), not over the whole tensor.
#[test]
fn test_softmax_axis_sums_to_one_per_lane() {
// 2x3x1x1 tensor; softmax along axis 1 (the size-3 axis).
let arr =
Array4::from_shape_vec([2, 3, 1, 1], vec![1.0f32, 2.0, 3.0, -1.0, 0.0, 1.0]).unwrap();
let t = Tensor::Float4D(arr);
let sm = t.softmax(1).unwrap();
let out = sm.as_array4().unwrap();
// Each lane along axis 1 must sum to 1.0.
for b in 0..2 {
let lane_sum: f32 = (0..3).map(|c| out[[b, c, 0, 0]]).sum();
assert!((lane_sum - 1.0).abs() < 1e-6, "lane {b} sum = {lane_sum}");
}
// Probabilities must be ordered like the logits within a lane.
assert!(out[[0, 0, 0, 0]] < out[[0, 1, 0, 0]]);
assert!(out[[0, 1, 0, 0]] < out[[0, 2, 0, 0]]);
}
// ADR-155 §Tier-2: softmax along different axes must give different
// results — the old global-softmax bug ignored the axis entirely.
#[test]
fn test_softmax_axis_choice_matters() {
let arr = Array4::from_shape_vec([1, 2, 2, 1], vec![1.0f32, 2.0, 3.0, 4.0]).unwrap();
let t = Tensor::Float4D(arr);
let along1 = t.softmax(1).unwrap();
let along2 = t.softmax(2).unwrap();
let a1 = along1.as_array4().unwrap();
let a2 = along2.as_array4().unwrap();
// The two normalizations partition the values differently, so at least
// one element must differ.
let mut differs = false;
for h in 0..2 {
if (a1[[0, 0, h, 0]] - a2[[0, 0, h, 0]]).abs() > 1e-6 {
differs = true;
}
}
assert!(differs, "softmax along axis 1 must differ from axis 2");
}
// ADR-155 §Tier-2: known-value check on a tiny tensor.
#[test]
fn test_softmax_known_values() {
// Lane [0, ln(3)] along axis 1 → softmax = [1/4, 3/4].
let arr = Array4::from_shape_vec([1, 2, 1, 1], vec![0.0f32, 3.0f32.ln()]).unwrap();
let t = Tensor::Float4D(arr);
let out = t.softmax(1).unwrap();
let a = out.as_array4().unwrap();
assert!((a[[0, 0, 0, 0]] - 0.25).abs() < 1e-6);
assert!((a[[0, 1, 0, 0]] - 0.75).abs() < 1e-6);
}
// ADR-155 §Tier-2: out-of-range axis must return an error, never panic.
#[test]
fn test_softmax_axis_out_of_range_errors() {
let t = Tensor::zeros_4d([1, 2, 2, 2]);
assert!(t.softmax(4).is_err());
assert!(t.softmax(99).is_err());
}
#[test]
fn test_broadcast_compatible() {
let a = TensorShape::new(vec![1, 3, 224, 224]);
+170 -12
View File
@@ -556,34 +556,122 @@ impl ModalityTranslator {
}
}
/// Apply multi-head attention
/// Apply single-head scaled-dot-product attention over the spatial
/// sequence: `softmax(Q·Kᵀ / √d) · V`, with `Q/K/V` linear projections of
/// each token's channel vector and a final output projection.
///
/// The spatial grid `[B, C, H, W]` is treated as a length-`H·W` token
/// sequence of `C`-dim feature vectors. Each `*_weight` projection is a
/// `[C × C]` matrix applied per token. This is a genuine attention
/// operation (not the previous uniform-weight identity stub), so the
/// returned per-pair attention weights actually depend on the input.
///
/// # Errors
/// Returns an error if any projection weight is not `[C × C]`, so a
/// mis-shaped checkpoint can never be silently treated as a no-op.
fn apply_attention(
&self,
input: &Array4<f32>,
_weights: &AttentionWeights,
weights: &AttentionWeights,
) -> NnResult<(Array4<f32>, Array4<f32>)> {
let (batch, channels, height, width) = input.dim();
let seq_len = height * width;
// Flatten spatial dimensions
let mut flat = ndarray::Array2::zeros((batch, seq_len * channels));
// Every projection must be a square [C × C] matrix to act per token.
for (name, w) in [
("query_weight", &weights.query_weight),
("key_weight", &weights.key_weight),
("value_weight", &weights.value_weight),
("output_weight", &weights.output_weight),
] {
if w.dim() != (channels, channels) {
return Err(NnError::invalid_input(format!(
"attention {name} must be [{channels} x {channels}], got [{} x {}]",
w.dim().0,
w.dim().1
)));
}
}
if weights.output_bias.len() != channels {
return Err(NnError::shape_mismatch(
vec![channels],
vec![weights.output_bias.len()],
));
}
// Flatten spatial grid into a [seq_len, channels] token matrix per batch.
// Project to Q, K, V; compute scaled-dot-product attention; project out.
let scale = 1.0 / (channels as f32).sqrt();
let mut out = Array4::zeros((batch, channels, height, width));
let mut attention_weights = Array4::zeros((batch, 1, seq_len, seq_len));
for b in 0..batch {
// Tokens: [seq_len, channels].
let mut tokens = ndarray::Array2::<f32>::zeros((seq_len, channels));
for h in 0..height {
for w in 0..width {
let s = h * width + w;
for c in 0..channels {
flat[[b, (h * width + w) * channels + c]] = input[[b, c, h, w]];
tokens[[s, c]] = input[[b, c, h, w]];
}
}
}
// Q = tokens·Wqᵀ, etc. (row vector × [C×C] projection).
let q = tokens.dot(&weights.query_weight.t());
let k = tokens.dot(&weights.key_weight.t());
let v = tokens.dot(&weights.value_weight.t());
// Scores = softmax_row(Q·Kᵀ · scale), then context = Scores·V.
let scores = q.dot(&k.t()).mapv(|x| x * scale);
for i in 0..seq_len {
// Numerically-stable row softmax.
let mut max = f32::NEG_INFINITY;
for j in 0..seq_len {
max = max.max(scores[[i, j]]);
}
let mut sum = 0.0f32;
let mut row = vec![0.0f32; seq_len];
for j in 0..seq_len {
let e = (scores[[i, j]] - max).exp();
row[j] = e;
sum += e;
}
if sum > 0.0 {
for j in 0..seq_len {
row[j] /= sum;
}
}
for j in 0..seq_len {
attention_weights[[b, 0, i, j]] = row[j];
}
}
// Context = attention · V, then output projection + bias.
for h in 0..height {
for w in 0..width {
let i = h * width + w;
// ctx[c] = Σ_j attn[i,j] · v[j,c]
let mut ctx = vec![0.0f32; channels];
for j in 0..seq_len {
let a = attention_weights[[b, 0, i, j]];
for c in 0..channels {
ctx[c] += a * v[[j, c]];
}
}
// out[c] = Σ_c' ctx[c'] · Wo[c, c'] + bias[c]
for c in 0..channels {
let mut acc = weights.output_bias[c];
for cp in 0..channels {
acc += ctx[cp] * weights.output_weight[[c, cp]];
}
out[[b, c, h, w]] = acc;
}
}
}
}
// For simplicity, return input unchanged with identity attention
let attention_weights = Array4::from_elem(
(batch, self.config.attention_heads, seq_len, seq_len),
1.0 / seq_len as f32,
);
Ok((input.clone(), attention_weights))
Ok((out, attention_weights))
}
/// Compute translation loss between predicted and target features
@@ -760,6 +848,76 @@ mod tests {
assert_eq!(config.activation, ActivationType::GELU);
}
// ADR-155 §Tier-2: apply_attention must perform real scaled-dot-product
// attention, not return uniform 1/seq_len weights. With identity Q/K/V
// projections and a non-uniform input, the attention weights must NOT all
// equal 1/seq_len, and each row must still be a valid distribution.
#[test]
fn test_attention_is_not_uniform_stub() {
let channels = 4usize;
let height = 2usize;
let width = 2usize;
let seq_len = height * width;
// Identity projections so Q=K=V=tokens; output = identity, zero bias.
let identity = ndarray::Array2::<f32>::eye(channels);
let weights = AttentionWeights {
query_weight: identity.clone(),
key_weight: identity.clone(),
value_weight: identity.clone(),
output_weight: identity,
output_bias: ndarray::Array1::zeros(channels),
};
// Non-uniform input: each spatial location has a distinct feature vector.
let mut input = Array4::<f32>::zeros((1, channels, height, width));
for c in 0..channels {
for h in 0..height {
for w in 0..width {
input[[0, c, h, w]] = (c + 2 * h + 4 * w) as f32;
}
}
}
let config = TranslatorConfig::default().with_attention(1);
let translator = ModalityTranslator::new(config).unwrap();
let (out, attn) = translator.apply_attention(&input, &weights).unwrap();
// Each attention row must sum to 1 (valid softmax distribution).
for i in 0..seq_len {
let row_sum: f32 = (0..seq_len).map(|j| attn[[0, 0, i, j]]).sum();
assert!((row_sum - 1.0).abs() < 1e-5, "row {i} sum = {row_sum}");
}
// Weights must NOT all be the uniform 1/seq_len value of the old stub.
let uniform = 1.0 / seq_len as f32;
let any_non_uniform = (0..seq_len)
.flat_map(|i| (0..seq_len).map(move |j| (i, j)))
.any(|(i, j)| (attn[[0, 0, i, j]] - uniform).abs() > 1e-4);
assert!(any_non_uniform, "attention collapsed to uniform stub");
// Output is finite and shaped like the input.
assert_eq!(out.dim(), input.dim());
assert!(out.iter().all(|v| v.is_finite()));
}
// ADR-155 §Tier-2: a mis-shaped projection weight must be rejected, never
// silently treated as a no-op.
#[test]
fn test_attention_rejects_wrong_weight_shape() {
let channels = 4usize;
let bad = ndarray::Array2::<f32>::zeros((channels + 1, channels));
let weights = AttentionWeights {
query_weight: bad.clone(),
key_weight: bad.clone(),
value_weight: bad.clone(),
output_weight: bad,
output_bias: ndarray::Array1::zeros(channels),
};
let input = Array4::<f32>::zeros((1, channels, 2, 2));
let config = TranslatorConfig::default().with_attention(1);
let translator = ModalityTranslator::new(config).unwrap();
assert!(translator.apply_attention(&input, &weights).is_err());
}
#[test]
fn test_loss_computation() {
let config = TranslatorConfig::default();