> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fincept.in/llms.txt
> Use this file to discover all available pages before exploring further.

# Stationarity Transformations

> Transforms time series to achieve stationarity using differencing, log returns, or simple returns. Includes ADF (Augmented Dickey-Fuller) test statistic. Critical for time series modeling and forecasting. [Tier: ENTERPRISE, Credits: 10]



## OpenAPI

````yaml api-specs/ml.json post /quantlib/ml/preprocessing/stationarity
openapi: 3.1.0
info:
  title: FinceptQuantLib API - ML
  description: >-
    Machine Learning and Credit Risk module endpoints for FinceptQuantLib API.
    Pro Tier access required (5 credits per request). Covers credit scoring,
    model validation, regression models, clustering, anomaly detection, feature
    engineering, and preprocessing.
  version: 3.0.0
  contact:
    name: Fincept API Support
    url: https://fincept.in
servers:
  - url: https://api.fincept.in
    description: Fincept API Production Server
security:
  - APIKeyHeader: []
tags:
  - name: quantlib-ml
    description: Machine Learning and Credit Risk Analytics
    x-displayName: ML
paths:
  /quantlib/ml/preprocessing/stationarity:
    post:
      tags:
        - quantlib-ml
      summary: Stationarity Transformations
      description: >-
        Transforms time series to achieve stationarity using differencing, log
        returns, or simple returns. Includes ADF (Augmented Dickey-Fuller) test
        statistic. Critical for time series modeling and forecasting. [Tier:
        ENTERPRISE, Credits: 10]
      operationId: stationarity_transform
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - data
              properties:
                data:
                  type: array
                  description: Time series data
                  items:
                    type: number
                  example:
                    - 100
                    - 102
                    - 101
                    - 105
                    - 107
                    - 106
                    - 110
                transform:
                  type: string
                  description: Transformation method
                  enum:
                    - difference
                    - log_returns
                    - simple_returns
                  default: difference
                  example: log_returns
      responses:
        '200':
          description: Transformed data with stationarity test
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                    example: true
                  data:
                    type: object
                    properties:
                      transformed:
                        type: array
                        items:
                          type: number
                        description: Transformed stationary series
                        example:
                          - 0.0198
                          - -0.0098
                          - 0.0385
                          - 0.0187
                          - -0.0093
                          - 0.037
                      adf_statistic:
                        type: number
                        description: ADF test statistic (more negative = more stationary)
                        example: -3.456
                      transform:
                        type: string
                        example: log_returns
        '401':
          $ref: '#/components/responses/UnauthorizedError'
        '402':
          $ref: '#/components/responses/InsufficientCreditsError'
        '422':
          $ref: '#/components/responses/ValidationError'
components:
  responses:
    UnauthorizedError:
      description: Authentication information is missing or invalid
      content:
        application/json:
          schema:
            type: object
            properties:
              detail:
                type: string
                example: Invalid API key
    InsufficientCreditsError:
      description: Insufficient credits for this operation
      content:
        application/json:
          schema:
            type: object
            properties:
              detail:
                type: string
                example: Insufficient credits. This endpoint requires 5 credits.
    ValidationError:
      description: Request validation error
      content:
        application/json:
          schema:
            type: object
            properties:
              detail:
                type: array
                items:
                  type: object
                  properties:
                    loc:
                      type: array
                      items:
                        type: string
                    msg:
                      type: string
                    type:
                      type: string
  securitySchemes:
    APIKeyHeader:
      type: apiKey
      in: header
      name: X-API-Key
      description: >-
        API key for authentication. Get your key at
        https://api.fincept.in/auth/register

````