action portfoliooptimizer_post_portfolio_analysis_tracking_error {
  label: "Tracking Error"
  description: "Compute the tracking error between a benchmark and one or several portfolio(s).\n\nReferences\n* [Wikipedia, Tracking error](https://en.wikipedia.org/wiki/Tracking_error) \n* Carl R. Bacon, Practical Portfolio Performance Measurement and Attribution \n"
  provider: portfoliooptimizer
  method: POST
  path: "/portfolio/analysis/tracking-error"
  encoding: json
  input: {
    type: "object"
    required: ["benchmarkReturns", "portfolios"]
    properties: {
      benchmarkReturns: {
        type: "array"
        description: "benchmarkReturns[t] is the return of the benchmark at the time t; the benchmarkReturns array must have the same length as all the portfolioReturns arrays"
        items: {
          type: "number"
        }
      }
      portfolios: {
        type: "array"
        items: {
          type: "object"
          required: ["portfolioReturns"]
          properties: {
            portfolioReturns: {
              type: "array"
              description: "portfolioReturns[t] is the return of the portfolio at the time t, the portfolioReturns must have the same length as the benchmarkReturns array"
              items: {
                type: "number"
              }
            }
          }
        }
      }
    }
  }
  output: {
    type: "object"
    required: ["portfolios"]
    properties: {
      portfolios: {
        type: "array"
        items: {
          type: "object"
          required: ["portfolioTrackingError"]
          properties: {
            portfolioTrackingError: {
              type: "number"
              description: "The tracking error of the portfolio"
            }
          }
        }
      }
    }
  }
}