Learn AI.

Diagnose a training run.

This playground now belongs to a full lesson and hands-on project.

Open the six-stage lesson · Project and independent transfer assessment. Learner pilots remain pending.

This 13-parameter network fits the supplied curve y = 0.5x + 0.35 sin(3x). Gradients use 32 training inputs; 32 different interleaved inputs monitor validation. Both come from the same known synthetic function. Repeated validation is development evidence, not an untouched final test. Capture matched runs below before navigating away.

Experiment: change one cause

Changing a training control restarts from the same initialization and clears optimizer moments. Save a comparison first. No automatic training or animation starts.

Choose a failure case, predict its signature, then train.

0 / 1,000accepted updates

6.089e-2training mean squared error

6.257e-2validation mean squared error

0 / 128hidden outputs with |h| > 0.99

+1.50−1.5−101
Dots: target. Line: model. Shared fixed scales. All plotted predictions are in range.
10⁶110⁻⁶0Updates1,000
Solid: training; dashed: validation. Logarithmic vertical scale: equal distances mean equal ratios. Values below 10⁻⁶ plot at the floor; exact losses are shown above.

Computed gradient norm: 3.534e-1 · gradient norm sent to optimizer: 3.534e-1. A nonzero computed gradient with zero applied gradient is evidence of the simulated blocked-gradient bug. Small gradients with many saturated units suggest inspecting scale.

Inspect the actual calculation

Scaled input: 0.50 · prediction: 0.408154 · target: 0.599123 · error: -0.190969.

Current model and proposed next update (all gradients averaged over training examples)
ParameterValueComputed gradientApplied gradientProposed change
w₁[0]0.400000-0.039147-0.0391473.9147e-3
ANIMATED WALKTHROUGH

A worked pass using your current model

1 / 4

x = 0.5; scaled input = 0.5. Hidden unit 0 receives 0.400 × 0.5 + 0.100.

Multiply x by the chosen input scale, then apply four learned weights and biases.

Playground values are temporary. Capture a finished run to save project evidence locally; captures and reports are included in My Work backups. Four evidence slots are available per project.

Open project and assessments
Extend the diagnosis: real-data neural failures
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