Experiment Report: burgers (pysindy)

Metadata

Algorithmpysindy
Datasetburgers
Expression\( u_{t} = - u u_{x} + 0.1002 u_{xx} \)
Best NMSE1.11783e-05
R²0.999989
NMSE1.118e-05
Iterations1
Early StoppedFalse
config.algorithmpysindy
config.library_fingerprint017dbdceae9f468d
config.terms['u', 'u_x', 'u_xx', 'u*u_x']
config.threshold0.05
config.max_iter20
config.normalize_columnsFalse
config.unbiasTrue
config.seed0
config.extra_optimizer_kwargsNone
config.provider_kindfinite_diff

Convergence

Convergence

Read the best native score reached at each search iteration.

Parity

Parity

Compare predicted and observed targets against the diagonal of exact agreement.

Equation

Equation

Read the published equation with its fitted coefficients and active terms.

Equation Tree

Equation Tree

Read the operators and derivatives that compose the published equation.

Residual

Residual

Read the distribution and spatial pattern of predicted minus observed target values.

Coefficient Bar

Coefficient Bar

Compare the magnitudes and signs of the active fitted coefficients.

Field Comparison

Field Comparison

Compare the measured field with forward integration of the discovered equation and their difference.

Pde Residual Field

Pde Residual Field

Compare the fitted derivative target with the equation prediction and their residual, without forward integration.

Time Slices

Time Slices

Compare measured and integrated fields at the labeled observation times.

Error Heatmap

Error Heatmap

Locate the signed field error from forward integration at the labeled physical coordinates.

Plugin Plots

Native vs Refit NMSE

Native vs Refit NMSE

pysindy's native-coefficient NMSE vs kd's independent refit re-score for the one selected STLSQ model -- do the two scores agree? Support size annotated.

Warnings

Integration boundary on 'x': periodic.
Field comparison, time slices and error heatmap were regenerated with corrected periodic spatial boundaries. The equation, coefficients and search-fit metrics remain those of the original run; no search was repeated.
Full result (JSON, for debugging) — click to expand
{
  "result_schema_version": 1,
  "best_expression": "add(u_xx, mul(u,u_x))",
  "best_score": 1.1178326915795506e-05,
  "iterations": 1,
  "early_stopped": false,
  "final_eval": {
    "mse": 7.631660410276492e-08,
    "nmse": 1.1178326915795506e-05,
    "r2": 0.9999888216730842,
    "score": -843276.2397612393,
    "complexity": 2,
    "coefficients": [
      0.0,
      0.0,
      0.10018764436244965,
      -1.0000022649765015
    ],
    "is_valid": true,
    "error_message": "",
    "invalid_reason": null,
    "selected_indices": [
      2,
      3
    ],
    "residuals": "[51456 elements]",
    "terms": [
      "u",
      "u_x",
      "u_xx",
      "mul(u,u_x)"
    ],
    "expression": "add(u_xx, mul(u,u_x))",
    "lhs_name": null,
    "condition_number": null,
    "condition_number_computed": false
  },
  "actual": "[51456 elements]",
  "predicted": "[51456 elements]",
  "dataset_name": "burgers",
  "algorithm_name": "PySINDyPlugin",
  "config": {
    "algorithm": "pysindy",
    "library_fingerprint": "017dbdceae9f468d",
    "terms": [
      "u",
      "u_x",
      "u_xx",
      "mul(u,u_x)"
    ],
    "threshold": 0.05,
    "max_iter": 20,
    "normalize_columns": false,
    "unbias": true,
    "seed": 0,
    "extra_optimizer_kwargs": null,
    "provider_kind": "finite_diff"
  },
  "recorder": {
    "native_nmse": [
      1.1178326915795506e-05
    ],
    "refit_nmse": [
      1.1178326915795547e-05
    ],
    "support_size": [
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    ],
    "stlsq_history": [
      [
        [
          8.639945813858149e-05,
          2.1504699826424556e-09,
          0.10021960833583707,
          -1.0002458992828476
        ],
        [
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          0.10020081617748726,
          -1.0000694092622109
        ],
        [
          0.0,
          0.0,
          0.10017314688254167,
          -0.9998584575380975
        ]
      ]
    ],
    "_best_score": [
      1.1178326915795506e-05
    ],
    "_best_expr": [
      "add(u_xx, mul(u,u_x))"
    ],
    "_n_candidates": [
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    ]
  },
  "lhs_label": "u_t",
  "equation": {
    "form": "EVOLUTION",
    "lhs_spec": {
      "field": "u",
      "axis": "t",
      "order": 1
    },
    "terms": [
      [
        "u",
        {
          "kind": "Scalar",
          "value": 0.0
        }
      ],
      [
        "u_x",
        {
          "kind": "Scalar",
          "value": 0.0
        }
      ],
      [
        "u_xx",
        {
          "kind": "Scalar",
          "value": 0.10018764586954051
        }
      ],
      [
        "mul(u,u_x)",
        {
          "kind": "Scalar",
          "value": -1.0000022081692426
        }
      ]
    ],
    "attrs": null,
    "active_indices": [
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      3
    ]
  },
  "manifest": {
    "dataset_cache_fingerprint": "burgers:grid:u:t:lhs_order=1:x,t:periodic=t=N,x=N_u(256, 201)_fb43be53",
    "kd_version": "0.7.5",
    "seed": 0,
    "terms": [
      "u",
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      "u_xx",
      "mul(u,u_x)"
    ],
    "artifacts": null,
    "resumed": false,
    "resume_source": null
  },
  "run_record": {
    "schema_version": 2,
    "evidence_hash_scheme": "kd-evidence-v1",
    "created_at": "2026-09-14T04:33:54+00:00",
    "cost": {
      "wallclock_seconds": 2.295153263024986,
      "search_seconds": 2.286355511052534,
      "boundary_results": 1,
      "boundary_invalid_results": 0,
      "preprocessing_seconds": 0.008797751972451806,
      "surrogate_train_seconds": null,
      "cpu_seconds": 2.2585239999999995,
      "tokens_in": null,
      "tokens_out": null,
      "tokens_cached": null,
      "api_cost_usd": null
    },
    "evidence": {
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      "dataset_name": "burgers",
      "dataset_cache_fingerprint": "burgers:grid:u:t:lhs_order=1:x,t:periodic=t=N,x=N_u(256, 201)_fb43be53",
      "seed": 0,
      "is_valid": true,
      "expression": "add(u_xx, mul(u,u_x))",
      "score_kind": "NMSE",
      "score_direction": "min",
      "headline_coefficient_source": "native",
      "catalog_fit": {
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        "lhs_spec": {
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        },
        "terms": [
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              "kind": "Scalar",
              "value": 0.0
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          ],
          [
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          ],
          [
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            {
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          ],
          [
            "mul(u,u_x)",
            {
              "kind": "Scalar",
              "value": -1.0000022081692426
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          ]
        ],
        "attrs": null,
        "active_indices": [
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        ]
      },
      "support": [
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        "mul(u,u_x)"
      ],
      "coefficients": [
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      "complexity": 2,
      "mse": 7.631660410276492e-08,
      "nmse": 1.1178326915795506e-05,
      "r2": 0.9999888216730842,
      "score": 1.1178326915795506e-05,
      "residual_stats": {
        "mean": -1.3669638288923916e-09,
        "std": 0.0002762572845603881,
        "max_abs": 0.0038285049487423884,
        "n": 51456
      },
      "invalid_reason": null,
      "error_detail": null
    },
    "evidence_hash": "5c6fd84428860261db401eb095a2fcfee906d67241fca41e9dd90c602b0e9242",
    "run_spec": {
      "kd_version": "0.7.5",
      "config": {
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        "extra_optimizer_kwargs": null,
        "library_fingerprint": "017dbdceae9f468d",
        "max_iter": 20,
        "normalize_columns": false,
        "provider_kind": "finite_diff",
        "seed": 0,
        "terms": [
          "u",
          "u_x",
          "u_xx",
          "mul(u,u_x)"
        ],
        "threshold": 0.05,
        "unbias": true
      },
      "dataset_cache_fingerprint": "burgers:grid:u:t:lhs_order=1:x,t:periodic=t=N,x=N_u(256, 201)_fb43be53",
      "library_fingerprint": "017dbdceae9f468d",
      "artifacts": null,
      "config_canon_scheme": "kd-config-v1"
    },
    "run_spec_hash": "5877d8d214e6f610942d5e74ae4b71f27128bb8a84327b4a2330ab255bdf9baf",
    "run_spec_hash_scheme": "kd-runspec-v1",
    "record_hash": "97fd9f89ca37ca9c4c48814d8ee97ce62a1e97588a0b8a4f8a3d2c8a407c6aa0",
    "record_hash_scheme": "kd-record-v1"
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  "score_kind": "NMSE",
  "score_direction": "min"
}