{
  "__type": "IngestedDoc",
  "__tag": 4010,
  "_content": {
    "Notes": {
      "__type": "Section",
      "__tag": 4015,
      "children": [
        {
          "__type": "Paragraph",
          "__tag": 4045,
          "children": [
            {
              "__type": "Text",
              "__tag": 4046,
              "value": "With "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "n = len(y)"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": ", compute "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "m_j"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " as the median of the slopes from the point "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "(x[j], y[j])"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " to all other "
            },
            {
              "__type": "InlineRole",
              "__tag": 4003,
              "value": "n-1",
              "domain": null,
              "role": null,
              "inventory": null
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " points. "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "slope"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " is then the median of all slopes "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "m_j"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": ". Two ways are given to estimate the intercept in "
            },
            {
              "__type": "FootnoteReference",
              "__tag": 4066,
              "label": "1"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " which can be chosen via the parameter "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "method"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": ". The hierarchical approach uses the estimated slope "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "slope"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " and computes "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "intercept"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " as the median of "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "y - slope*x"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": ". The other approach estimates the intercept separately as follows: for each point "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "(x[j], y[j])"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": ", compute the intercepts of all the "
            },
            {
              "__type": "InlineRole",
              "__tag": 4003,
              "value": "n-1",
              "domain": null,
              "role": null,
              "inventory": null
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " lines through the remaining points and take the median "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "i_j"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": ". "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "intercept"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " is the median of the "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "i_j"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": "."
            }
          ]
        },
        {
          "__type": "Paragraph",
          "__tag": 4045,
          "children": [
            {
              "__type": "Text",
              "__tag": 4046,
              "value": "The implementation computes "
            },
            {
              "__type": "InlineRole",
              "__tag": 4003,
              "value": "n",
              "domain": null,
              "role": null,
              "inventory": null
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " times the median of a vector of size "
            },
            {
              "__type": "InlineRole",
              "__tag": 4003,
              "value": "n",
              "domain": null,
              "role": null,
              "inventory": null
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " which can be slow for large vectors. There are more efficient algorithms (see "
            },
            {
              "__type": "FootnoteReference",
              "__tag": 4066,
              "label": "2"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": ") which are not implemented here."
            }
          ]
        },
        {
          "__type": "Paragraph",
          "__tag": 4045,
          "children": [
            {
              "__type": "Text",
              "__tag": 4046,
              "value": "For compatibility with older versions of SciPy, the return value acts like a "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "namedtuple"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " of length 2, with fields "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "slope"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " and "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "intercept"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": ", so one can continue to write      "
            }
          ]
        },
        {
          "__type": "Code",
          "__tag": 4050,
          "value": "slope, intercept = siegelslopes(y, x)",
          "execution_status": null
        },
        {
          "__type": "Paragraph",
          "__tag": 4045,
          "children": [
            {
              "__type": "Text",
              "__tag": 4046,
              "value": "Beginning in SciPy 1.9, "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "np.matrix"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " inputs (not recommended for new code) are converted to "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "np.ndarray"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " before the calculation is performed. In this case, the output will be a scalar or "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "np.ndarray"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " of appropriate shape rather than a 2D "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "np.matrix"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": ". Similarly, while masked elements of masked arrays are ignored, the output will be a scalar or "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "np.ndarray"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " rather than a masked array with "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "mask=False"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": "."
            }
          ]
        },
        {
          "__type": "Paragraph",
          "__tag": 4045,
          "children": [
            {
              "__type": "Strong",
              "__tag": 4048,
              "children": [
                {
                  "__type": "Text",
                  "__tag": 4046,
                  "value": "Array API Standard Support"
                }
              ]
            }
          ]
        },
        {
          "__type": "Paragraph",
          "__tag": 4045,
          "children": [
            {
              "__type": "InlineRole",
              "__tag": 4003,
              "value": "siegelslopes",
              "domain": null,
              "role": null,
              "inventory": null
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " has experimental support for Python Array API Standard compatible backends in addition to NumPy. Please consider testing these features by setting an environment variable "
            },
            {
              "__type": "InlineCode",
              "__tag": 4051,
              "value": "SCIPY_ARRAY_API=1"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " and providing CuPy, PyTorch, JAX, or Dask arrays as array arguments. The following combinations of backend and device (or other capability) are supported."
            }
          ]
        },
        {
          "__type": "Code",
          "__tag": 4050,
          "value": "====================  ====================  ====================\nLibrary               CPU                   GPU\n====================  ====================  ====================\nNumPy                 ✅                     n/a                 \nCuPy                  n/a                   ⛔                   \nPyTorch               ⛔                     ⛔                   \nJAX                   ⛔                     ⛔                   \nDask                  ⛔                     n/a                 \n====================  ====================  ====================",
          "execution_status": null
        },
        {
          "__type": "Blockquote",
          "__tag": 4059,
          "children": [
            {
              "__type": "Paragraph",
              "__tag": 4045,
              "children": [
                {
                  "__type": "Text",
                  "__tag": 4046,
                  "value": "See "
                },
                {
                  "__type": "InlineRole",
                  "__tag": 4003,
                  "value": "dev-arrayapi",
                  "domain": null,
                  "role": "ref",
                  "inventory": null
                },
                {
                  "__type": "Text",
                  "__tag": 4046,
                  "value": " for more information."
                }
              ]
            }
          ]
        }
      ],
      "title": [],
      "level": 0,
      "target": null
    },
    "Warns": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Raises": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Yields": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Methods": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Returns": {
      "__type": "Section",
      "__tag": 4015,
      "children": [
        {
          "__type": "Parameters",
          "__tag": 4026,
          "children": [
            {
              "__type": "DocParam",
              "__tag": 4016,
              "name": "result",
              "annotation": "``SiegelslopesResult`` instance",
              "desc": [
                {
                  "__type": "Paragraph",
                  "__tag": 4045,
                  "children": [
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": "The return value is an object with the following attributes:"
                    }
                  ]
                },
                {
                  "__type": "DefList",
                  "__tag": 4033,
                  "children": [
                    {
                      "__type": "DefListItem",
                      "__tag": 4037,
                      "dt": {
                        "__type": "Paragraph",
                        "__tag": 4045,
                        "children": [
                          {
                            "__type": "Text",
                            "__tag": 4046,
                            "value": "slope"
                          }
                        ]
                      },
                      "dd": [
                        {
                          "__type": "Paragraph",
                          "__tag": 4045,
                          "children": [
                            {
                              "__type": "Text",
                              "__tag": 4046,
                              "value": "slope"
                            }
                          ]
                        }
                      ]
                    },
                    {
                      "__type": "DefListItem",
                      "__tag": 4037,
                      "dt": {
                        "__type": "Paragraph",
                        "__tag": 4045,
                        "children": [
                          {
                            "__type": "Text",
                            "__tag": 4046,
                            "value": "intercept"
                          }
                        ]
                      },
                      "dd": [
                        {
                          "__type": "Paragraph",
                          "__tag": 4045,
                          "children": [
                            {
                              "__type": "Text",
                              "__tag": 4046,
                              "value": "intercept"
                            }
                          ]
                        }
                      ]
                    }
                  ]
                }
              ]
            }
          ]
        }
      ],
      "title": [],
      "level": 0,
      "target": null
    },
    "Summary": {
      "__type": "Section",
      "__tag": 4015,
      "children": [
        {
          "__type": "Paragraph",
          "__tag": 4045,
          "children": [
            {
              "__type": "Text",
              "__tag": 4046,
              "value": "Computes the Siegel estimator for a set of points (x, y)."
            }
          ]
        }
      ],
      "title": [],
      "level": 0,
      "target": null
    },
    "Receives": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Warnings": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Attributes": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    },
    "Parameters": {
      "__type": "Section",
      "__tag": 4015,
      "children": [
        {
          "__type": "Parameters",
          "__tag": 4026,
          "children": [
            {
              "__type": "DocParam",
              "__tag": 4016,
              "name": "y",
              "annotation": "array_like",
              "desc": [
                {
                  "__type": "Paragraph",
                  "__tag": 4045,
                  "children": [
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": "Dependent variable."
                    }
                  ]
                }
              ]
            },
            {
              "__type": "DocParam",
              "__tag": 4016,
              "name": "x",
              "annotation": "array_like or None, optional",
              "desc": [
                {
                  "__type": "Paragraph",
                  "__tag": 4045,
                  "children": [
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": "Independent variable. If None, use "
                    },
                    {
                      "__type": "InlineCode",
                      "__tag": 4051,
                      "value": "arange(len(y))"
                    },
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": " instead."
                    }
                  ]
                }
              ]
            },
            {
              "__type": "DocParam",
              "__tag": 4016,
              "name": "method",
              "annotation": "{'hierarchical', 'separate'}",
              "desc": [
                {
                  "__type": "Paragraph",
                  "__tag": 4045,
                  "children": [
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": "If 'hierarchical', estimate the intercept using the estimated slope "
                    },
                    {
                      "__type": "InlineCode",
                      "__tag": 4051,
                      "value": "slope"
                    },
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": " (default option). If 'separate', estimate the intercept independent of the estimated slope. See Notes for details."
                    }
                  ]
                }
              ]
            },
            {
              "__type": "DocParam",
              "__tag": 4016,
              "name": "axis",
              "annotation": "int or None, default: None",
              "desc": [
                {
                  "__type": "Paragraph",
                  "__tag": 4045,
                  "children": [
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": "If an int, the axis of the input along which to compute the statistic. The statistic of each axis-slice (e.g. row) of the input will appear in a corresponding element of the output. If "
                    },
                    {
                      "__type": "InlineCode",
                      "__tag": 4051,
                      "value": "None"
                    },
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": ", the input will be raveled before computing the statistic."
                    }
                  ]
                }
              ]
            },
            {
              "__type": "DocParam",
              "__tag": 4016,
              "name": "nan_policy",
              "annotation": "{'propagate', 'omit', 'raise'}",
              "desc": [
                {
                  "__type": "Paragraph",
                  "__tag": 4045,
                  "children": [
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": "Defines how to handle input NaNs."
                    }
                  ]
                },
                {
                  "__type": "BulletList",
                  "__tag": 4053,
                  "ordered": false,
                  "start": 1,
                  "children": [
                    {
                      "__type": "ListItem",
                      "__tag": 4054,
                      "children": [
                        {
                          "__type": "Paragraph",
                          "__tag": 4045,
                          "children": [
                            {
                              "__type": "InlineCode",
                              "__tag": 4051,
                              "value": "propagate"
                            },
                            {
                              "__type": "Text",
                              "__tag": 4046,
                              "value": ": if a NaN is present in the axis slice (e.g. row) along   which the  statistic is computed, the corresponding entry of the output   will be NaN."
                            }
                          ]
                        }
                      ]
                    },
                    {
                      "__type": "ListItem",
                      "__tag": 4054,
                      "children": [
                        {
                          "__type": "Paragraph",
                          "__tag": 4045,
                          "children": [
                            {
                              "__type": "InlineCode",
                              "__tag": 4051,
                              "value": "omit"
                            },
                            {
                              "__type": "Text",
                              "__tag": 4046,
                              "value": ": NaNs will be omitted when performing the calculation.   If insufficient data remains in the axis slice along which the   statistic is computed, the corresponding entry of the output will be   NaN."
                            }
                          ]
                        }
                      ]
                    },
                    {
                      "__type": "ListItem",
                      "__tag": 4054,
                      "children": [
                        {
                          "__type": "Paragraph",
                          "__tag": 4045,
                          "children": [
                            {
                              "__type": "InlineCode",
                              "__tag": 4051,
                              "value": "raise"
                            },
                            {
                              "__type": "Text",
                              "__tag": 4046,
                              "value": ": if a NaN is present, a "
                            },
                            {
                              "__type": "InlineCode",
                              "__tag": 4051,
                              "value": "ValueError"
                            },
                            {
                              "__type": "Text",
                              "__tag": 4046,
                              "value": " will be raised."
                            }
                          ]
                        }
                      ]
                    }
                  ]
                }
              ]
            },
            {
              "__type": "DocParam",
              "__tag": 4016,
              "name": "keepdims",
              "annotation": "bool, default: False",
              "desc": [
                {
                  "__type": "Paragraph",
                  "__tag": 4045,
                  "children": [
                    {
                      "__type": "Text",
                      "__tag": 4046,
                      "value": "If this is set to True, the axes which are reduced are left in the result as dimensions with size one. With this option, the result will broadcast correctly against the input array."
                    }
                  ]
                }
              ]
            }
          ]
        }
      ],
      "title": [],
      "level": 0,
      "target": null
    },
    "Extended Summary": {
      "__type": "Section",
      "__tag": 4015,
      "children": [
        {
          "__type": "Paragraph",
          "__tag": 4045,
          "children": [
            {
              "__type": "InlineRole",
              "__tag": 4003,
              "value": "siegelslopes",
              "domain": null,
              "role": null,
              "inventory": null
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": " implements a method for robust linear regression using repeated medians (see "
            },
            {
              "__type": "FootnoteReference",
              "__tag": 4066,
              "label": "1"
            },
            {
              "__type": "Text",
              "__tag": 4046,
              "value": ") to fit a line to the points (x, y). The method is robust to outliers with an asymptotic breakdown point of 50%."
            }
          ]
        }
      ],
      "title": [],
      "level": 0,
      "target": null
    },
    "Other Parameters": {
      "__type": "Section",
      "__tag": 4015,
      "children": [],
      "title": [],
      "level": 0,
      "target": null
    }
  },
  "_ordered_sections": [
    "Summary",
    "Extended Summary",
    "Parameters",
    "Attributes",
    "Methods",
    "Returns",
    "Yields",
    "Receives",
    "Other Parameters",
    "Raises",
    "Warns",
    "Warnings",
    "Notes"
  ],
  "item_file": "/scipy/stats/_stats_mstats_common.py",
  "item_line": 208,
  "item_type": "function",
  "aliases": [
    "scipy.stats.siegelslopes"
  ],
  "example_section_data": {
    "__type": "Section",
    "__tag": 4015,
    "children": [
      {
        "__type": "Code",
        "__tag": 4050,
        "value": "import numpy as np\nfrom scipy import stats\nimport matplotlib.pyplot as plt\n",
        "execution_status": "success"
      },
      {
        "__type": "Text",
        "__tag": 4046,
        "value": "\n"
      },
      {
        "__type": "Code",
        "__tag": 4050,
        "value": "x = np.linspace(-5, 5, num=150)\ny = x + np.random.normal(size=x.size)\ny[11:15] += 10  # add outliers\ny[-5:] -= 7\n",
        "execution_status": "success"
      },
      {
        "__type": "Text",
        "__tag": 4046,
        "value": "\nCompute the slope and intercept.  For comparison, also compute the\nleast-squares fit with `linregress`:\n\n"
      },
      {
        "__type": "Code",
        "__tag": 4050,
        "value": "res = stats.siegelslopes(y, x)\nlsq_res = stats.linregress(x, y)\n",
        "execution_status": "success"
      },
      {
        "__type": "Text",
        "__tag": 4046,
        "value": "\nPlot the results. The Siegel regression line is shown in red. The green\nline shows the least-squares fit for comparison.\n\n"
      },
      {
        "__type": "Code",
        "__tag": 4050,
        "value": "fig = plt.figure()\nax = fig.add_subplot(111)\n",
        "execution_status": "success"
      },
      {
        "__type": "Code",
        "__tag": 4050,
        "value": "ax.plot(x, y, 'b.')\nax.plot(x, res[1] + res[0] * x, 'r-')\nax.plot(x, lsq_res[1] + lsq_res[0] * x, 'g-')\n",
        "execution_status": "failure"
      },
      {
        "__type": "Code",
        "__tag": 4050,
        "value": "plt.show()\n",
        "execution_status": "success"
      },
      {
        "__type": "Figure",
        "__tag": 4024,
        "value": {
          "__type": "RefInfo",
          "__tag": 4000,
          "module": "scipy",
          "version": "1.17.1",
          "kind": "assets",
          "path": "fig-31a8715527c70664.png"
        }
      }
    ],
    "title": [],
    "level": 0,
    "target": null
  },
  "see_also": [
    {
      "__type": "SeeAlsoItem",
      "__tag": 4028,
      "name": {
        "__type": "CrossRef",
        "__tag": 4002,
        "value": "theilslopes",
        "reference": {
          "__type": "RefInfo",
          "__tag": 4000,
          "module": "current-module",
          "version": "current-version",
          "kind": "to-resolve",
          "path": "theilslopes"
        },
        "kind": "module"
      },
      "descriptions": [
        {
          "__type": "Paragraph",
          "__tag": 4045,
          "children": [
            {
              "__type": "Text",
              "__tag": 4046,
              "value": "a similar technique without repeated medians"
            }
          ]
        }
      ],
      "type": "func"
    }
  ],
  "signature": {
    "__type": "SignatureNode",
    "__tag": 4029,
    "kind": "function",
    "parameters": [
      {
        "__type": "SigParam",
        "__tag": 4030,
        "name": "y",
        "annotation": {
          "__type": "Empty",
          "__tag": 4031
        },
        "kind": "POSITIONAL_OR_KEYWORD",
        "default": {
          "__type": "Empty",
          "__tag": 4031
        }
      },
      {
        "__type": "SigParam",
        "__tag": 4030,
        "name": "x",
        "annotation": {
          "__type": "Empty",
          "__tag": 4031
        },
        "kind": "POSITIONAL_OR_KEYWORD",
        "default": "None"
      },
      {
        "__type": "SigParam",
        "__tag": 4030,
        "name": "method",
        "annotation": {
          "__type": "Empty",
          "__tag": 4031
        },
        "kind": "POSITIONAL_OR_KEYWORD",
        "default": "hierarchical"
      },
      {
        "__type": "SigParam",
        "__tag": 4030,
        "name": "axis",
        "annotation": {
          "__type": "Empty",
          "__tag": 4031
        },
        "kind": "KEYWORD_ONLY",
        "default": "None"
      },
      {
        "__type": "SigParam",
        "__tag": 4030,
        "name": "nan_policy",
        "annotation": {
          "__type": "Empty",
          "__tag": 4031
        },
        "kind": "KEYWORD_ONLY",
        "default": "propagate"
      },
      {
        "__type": "SigParam",
        "__tag": 4030,
        "name": "keepdims",
        "annotation": {
          "__type": "Empty",
          "__tag": 4031
        },
        "kind": "KEYWORD_ONLY",
        "default": "False"
      }
    ],
    "return_annotation": {
      "__type": "Empty",
      "__tag": 4031
    },
    "target_name": "siegelslopes"
  },
  "references": [
    ".. [1] A. Siegel, \"Robust Regression Using Repeated Medians\",",
    "       Biometrika, Vol. 69, pp. 242-244, 1982.",
    "",
    ".. [2] A. Stein and M. Werman, \"Finding the repeated median regression",
    "       line\", Proceedings of the Third Annual ACM-SIAM Symposium on",
    "       Discrete Algorithms, pp. 409-413, 1992."
  ],
  "qa": "scipy.stats._stats_mstats_common:siegelslopes",
  "arbitrary": [],
  "local_refs": [
    "axis",
    "keepdims",
    "method",
    "nan_policy",
    "result",
    "x",
    "y"
  ]
}