---
url: >-
  https://jer-k.github.io/effect-prophet/benchmarks/flat/warm-start-flat-defaults-7-new-rows.md
---

# Refit after a week of new data

 [← All flat growth benchmarks](/benchmarks/flat)

`fit(history, { growth: "flat", map: { warmStart } })` from `warmStartParameters` of a fit of the first 89 days, against `fit(df, init=warm_start_params(m))`. 96 days around one level with a weekly rhythm, fitted with Newton. Timings compare the refit with a fresh fit.

## Input

[`benchmark/inputs/v1/flat-seasonal.json`](https://github.com/jer-k/effect-prophet/blob/main/benchmark/inputs/v1/flat-seasonal.json): 96 history rows and 24 forecast rows.

## Output

Largest difference: **5.6e-6** (0.00019% of the input's range).

Every forecast row from both libraries.

| Date | Effect Prophet | Python Prophet | Difference |
| --- | ---: | ---: | ---: |
| 2020-04-06 | 33.6334 | 33.6334 | 1.4e-6 |
| 2020-04-07 | 33.9115 | 33.9115 | 3.2e-6 |
| 2020-04-08 | 35.0025 | 35.0025 | 4.0e-6 |
| 2020-04-09 | 36.0968 | 36.0968 | 5.6e-6 |
| 2020-04-10 | 36.3663 | 36.3663 | 2.5e-6 |
| 2020-04-11 | 35.6078 | 35.6078 | 2.8e-6 |
| 2020-04-12 | 34.3921 | 34.3921 | 3.6e-6 |
| 2020-04-13 | 33.6334 | 33.6334 | 1.4e-6 |
| 2020-04-14 | 33.9115 | 33.9115 | 3.2e-6 |
| 2020-04-15 | 35.0025 | 35.0025 | 4.0e-6 |
| 2020-04-16 | 36.0968 | 36.0968 | 5.6e-6 |
| 2020-04-17 | 36.3663 | 36.3663 | 2.5e-6 |
| 2020-04-18 | 35.6078 | 35.6078 | 2.8e-6 |
| 2020-04-19 | 34.3921 | 34.3921 | 3.6e-6 |
| 2020-04-20 | 33.6334 | 33.6334 | 1.4e-6 |
| 2020-04-21 | 33.9115 | 33.9115 | 3.2e-6 |
| 2020-04-22 | 35.0025 | 35.0025 | 4.0e-6 |
| 2020-04-23 | 36.0968 | 36.0968 | 5.6e-6 |
| 2020-04-24 | 36.3663 | 36.3663 | 2.5e-6 |
| 2020-04-25 | 35.6078 | 35.6078 | 2.8e-6 |
| 2020-04-26 | 34.3921 | 34.3921 | 3.6e-6 |
| 2020-04-27 | 33.6334 | 33.6334 | 1.4e-6 |
| 2020-04-28 | 33.9115 | 33.9115 | 3.2e-6 |
| 2020-04-29 | 35.0025 | 35.0025 | 4.0e-6 |

## Timing

Median of all measured repetitions.

| Step | Effect Prophet | Python Prophet | Effect Prophet is |
| --- | ---: | ---: | --- |
| Fit | 110 ms | 389 ms | 3.5× faster |
| Refit from an earlier fit | 6.38 ms | 8.52 ms | 1.3× faster |

## Settings

The case declaration both libraries ran.

```json
{
  "kind": "map",
  "comparison": {
    "kind": "equivalent-objective",
    "evidenceId": "flat-growth-reduced-v1"
  },
  "fitRequest": "growth-only",
  "configuration": {
    "growth": "flat",
    "scaling": "absmax",
    "seasonalityMode": "additive",
    "holidaysMode": "additive",
    "changepoints": {
      "mode": "auto",
      "count": 25,
      "range": 0.8
    },
    "changepointPriorScale": 0.05,
    "seasonalities": [
      {
        "name": "weekly",
        "periodDays": 7,
        "fourierOrder": 3,
        "priorScale": 10
      }
    ],
    "events": [],
    "regressors": []
  },
  "pythonOptimizer": {
    "algorithm": "Auto",
    "maxIterations": 10000,
    "newtonFallback": true
  },
  "warmStart": {
    "baseRows": 89,
    "investigateParameterAbsolute": 0.01
  }
}
```