### Navigation

- index
- modules |
- modules |
- next |
- previous |
- SciPy v0.12 Reference Guide (DRAFT) »
- Orthogonal distance regression (`scipy.odr`) »

# scipy.odr.RealData

class `scipy.odr.``RealData`(x, y=None, sx=None, sy=None, covx=None, covy=None, fix=None, meta={})

  The RealData class stores the weightings as actual standard deviations and/or covariances.

  Parameters : | x : array_like x y : array_like, optional y sx, sy : array_like, optional Standard deviations of x. sx are standard deviations of x and are converted to weights by dividing 1.0 by their squares. sy : array_like, optional Standard deviations of y. sy are standard deviations of y and are converted to weights by dividing 1.0 by their squares. covx : array_like, optional Covariance of x covx is an array of covariance matrices of x and are converted to weights by performing a matrix inversion on each observation’s covariance matrix. covy : array_like, optional Covariance of y covy is an array of covariance matrices and are converted to weights by performing a matrix inversion on each observation’s covariance matrix. fix : array_like The argument and member fix is the same as Data.fix and ODR.ifixx: It is an array of integers with the same shape as x that determines which input observations are treated as fixed. One can use a sequence of length m (the dimensionality of the input observations) to fix some dimensions for all observations. A value of 0 fixes the observation, a value > 0 makes it free. meta : dict Meta

  Notes

  The weights needed for ODRPACK are generated on-the-fly with `__getattr__` trickery.

  sx and sy are converted to weights by dividing 1.0 by their squares. For example, `wd = 1./numpy.power(`sx`, 2)`.

  covx and covy are arrays of covariance matrices and are converted to weights by performing a matrix inversion on each observation’s covariance matrix. For example, `we[i] = numpy.linalg.inv(covy[i])`.

  These arguments follow the same structured argument conventions as wd and we only restricted by their natures: sx and sy can’t be rank-3, but covx and covy can be.

  Only set either sx or covx (not both). Setting both will raise an exception. Same with sy and covy.

  Methods

  `set_meta`(**kwds) | Update the metadata dictionary with the keywords and data provided by keywords.

### Navigation

- index
- modules |
- modules |
- next |
- previous |
- SciPy v0.12 Reference Guide (DRAFT) »
- Orthogonal distance regression (`scipy.odr`) »