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| 1 | +"""Solar production source-data filtering. |
| 2 | +
|
| 3 | +Removes physically implausible solar production observations from a source |
| 4 | +frame before analysis: negative production, zero production while a solar |
| 5 | +reference signal indicates meaningful production, and robust |
| 6 | +production-to-reference ratio outliers. |
| 7 | +
|
| 8 | +The filter removes rows; it never mutates values. Run it on raw (pre-resample) |
| 9 | +data so aggregated energy totals are computed from the retained observations. |
| 10 | +""" |
| 11 | + |
| 12 | +import numpy as np |
| 13 | +import pandas as pd |
| 14 | + |
| 15 | +from .models import FilteringDiagnostics, SolarSourceFilteringParameters |
| 16 | + |
| 17 | + |
| 18 | +def _resolve_reference_column( |
| 19 | + frame: pd.DataFrame, |
| 20 | + reference_column: str | None, |
| 21 | + parameters: SolarSourceFilteringParameters, |
| 22 | +) -> str | None: |
| 23 | + if reference_column is not None: |
| 24 | + if reference_column not in frame.columns: |
| 25 | + raise ValueError(f"Reference column '{reference_column}' not found in frame.") |
| 26 | + return reference_column |
| 27 | + |
| 28 | + for name in parameters.solar_reference_names: |
| 29 | + if name in frame.columns: |
| 30 | + return name |
| 31 | + |
| 32 | + for column in frame.columns: |
| 33 | + lower = column.lower() |
| 34 | + if "solar" in lower and ("generation" in lower or "radiation" in lower): |
| 35 | + return column |
| 36 | + |
| 37 | + return None |
| 38 | + |
| 39 | + |
| 40 | +def _positive_reference_threshold( |
| 41 | + series: pd.Series, |
| 42 | + parameters: SolarSourceFilteringParameters, |
| 43 | +) -> float: |
| 44 | + positive = series[series > 0] |
| 45 | + if positive.empty: |
| 46 | + return 0.0 |
| 47 | + return max( |
| 48 | + float(positive.median()) * parameters.positive_reference_median_fraction, |
| 49 | + parameters.minimum_positive_reference, |
| 50 | + ) |
| 51 | + |
| 52 | + |
| 53 | +def _robust_ratio_outlier_mask( |
| 54 | + ratio: pd.Series, |
| 55 | + parameters: SolarSourceFilteringParameters, |
| 56 | +) -> pd.Series: |
| 57 | + if len(ratio) < parameters.minimum_retained_rows: |
| 58 | + return pd.Series(False, index=ratio.index) |
| 59 | + |
| 60 | + median = float(ratio.median()) |
| 61 | + mad = float((ratio - median).abs().median()) |
| 62 | + if not np.isfinite(mad) or mad <= 0: |
| 63 | + q1 = float(ratio.quantile(0.25)) |
| 64 | + q3 = float(ratio.quantile(0.75)) |
| 65 | + iqr = q3 - q1 |
| 66 | + if not np.isfinite(iqr) or iqr <= 0: |
| 67 | + return pd.Series(False, index=ratio.index) |
| 68 | + return (ratio < q1 - parameters.ratio_iqr_multiplier * iqr) | ( |
| 69 | + ratio > q3 + parameters.ratio_iqr_multiplier * iqr |
| 70 | + ) |
| 71 | + |
| 72 | + robust_z = 0.6745 * (ratio - median).abs() / mad |
| 73 | + return robust_z > parameters.ratio_robust_z_threshold |
| 74 | + |
| 75 | + |
| 76 | +def clean_solar_production_frame( |
| 77 | + frame: pd.DataFrame, |
| 78 | + production_column: str, |
| 79 | + reference_column: str | None = None, |
| 80 | + parameters: SolarSourceFilteringParameters | None = None, |
| 81 | +) -> tuple[pd.DataFrame, FilteringDiagnostics]: |
| 82 | + """Remove invalid solar production observations from a source frame. |
| 83 | +
|
| 84 | + Returns the filtered frame and diagnostics. When guardrails reject the |
| 85 | + filtering (too few or too small a fraction of observations would remain), |
| 86 | + the original frame is returned untouched and the diagnostics keep the |
| 87 | + identified counts so callers can see what would have been removed. |
| 88 | + """ |
| 89 | + |
| 90 | + parameters = parameters or SolarSourceFilteringParameters() |
| 91 | + |
| 92 | + if production_column not in frame.columns: |
| 93 | + raise ValueError(f"Production column '{production_column}' not found in frame.") |
| 94 | + |
| 95 | + original_count = len(frame) |
| 96 | + diagnostics = FilteringDiagnostics( |
| 97 | + status="nothing-to-remove", |
| 98 | + originalObservationCount=original_count, |
| 99 | + retainedObservationCount=original_count, |
| 100 | + removedObservationCount=0, |
| 101 | + ) |
| 102 | + |
| 103 | + if original_count == 0: |
| 104 | + diagnostics.reason = "empty frame" |
| 105 | + return frame, diagnostics |
| 106 | + |
| 107 | + reference = _resolve_reference_column(frame, reference_column, parameters) |
| 108 | + |
| 109 | + # Numeric view used for mask computation only; the returned frame keeps |
| 110 | + # the original values. |
| 111 | + numeric = frame.apply(pd.to_numeric, errors="coerce") |
| 112 | + y = numeric[production_column] |
| 113 | + keep = pd.Series(True, index=numeric.index) |
| 114 | + |
| 115 | + negative_mask = y < 0 |
| 116 | + diagnostics.identified_negative_count = int(negative_mask.sum()) |
| 117 | + keep &= ~negative_mask |
| 118 | + |
| 119 | + if reference is not None: |
| 120 | + reference_series = numeric[reference] |
| 121 | + reference_threshold = _positive_reference_threshold(reference_series[keep], parameters) |
| 122 | + |
| 123 | + zero_with_solar_mask = (y <= 0) & (reference_series > reference_threshold) |
| 124 | + diagnostics.identified_zero_with_solar_count = int((keep & zero_with_solar_mask).sum()) |
| 125 | + keep &= ~zero_with_solar_mask |
| 126 | + |
| 127 | + ratio_candidates = ( |
| 128 | + keep |
| 129 | + & np.isfinite(y) |
| 130 | + & np.isfinite(reference_series) |
| 131 | + & (y > 0) |
| 132 | + & (reference_series > reference_threshold) |
| 133 | + ) |
| 134 | + ratios = y[ratio_candidates] / reference_series[ratio_candidates] |
| 135 | + ratio_outliers = _robust_ratio_outlier_mask(ratios, parameters) |
| 136 | + diagnostics.identified_ratio_outlier_count = int(ratio_outliers.sum()) |
| 137 | + keep.loc[ratio_outliers[ratio_outliers].index] = False |
| 138 | + |
| 139 | + retained_count = int(keep.sum()) |
| 140 | + identified_count = original_count - retained_count |
| 141 | + |
| 142 | + if identified_count == 0: |
| 143 | + diagnostics.reason = "no invalid solar observations identified" |
| 144 | + return frame, diagnostics |
| 145 | + |
| 146 | + if retained_count < parameters.minimum_retained_rows: |
| 147 | + diagnostics.status = "rejected-guardrail" |
| 148 | + diagnostics.reason = "too few observations would remain after filtering" |
| 149 | + return frame, diagnostics |
| 150 | + |
| 151 | + if retained_count / original_count < parameters.minimum_retained_fraction: |
| 152 | + diagnostics.status = "rejected-guardrail" |
| 153 | + diagnostics.reason = "too much source data would be removed" |
| 154 | + return frame, diagnostics |
| 155 | + |
| 156 | + diagnostics.status = "applied" |
| 157 | + diagnostics.retained_observation_count = retained_count |
| 158 | + diagnostics.removed_observation_count = identified_count |
| 159 | + diagnostics.reason = "solar production source-data filtering applied" |
| 160 | + return frame.loc[keep].copy(), diagnostics |
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