# Changeset 275

Ignore:
Timestamp:
Nov 19, 2012 12:28:35 AM (7 years ago)
Message:

examples for Jan Ilavsky and Brian Pauw

File:
1 edited

### Legend:

Unmodified
 r227 * generic 2-D I(Q)_ * simple 2-D (image) I(Q)_ * 1D SAS data in a time series I(t,Q)_ * 1D SAS data in a time series I(t,Q(t))_ Qy: float[100, 512] Qx: float[100, 512] .. _2-D (image) I(|Q|) with uncertainty: 2-D (image)  :math:I(|Q|)\pm\sigma(|Q|) ------------------------------------------------------ .. code-block:: text :linenos: SASroot SASentry SASdata @Q_indices=0,1 @I_axes="Q,Q" I: float[300, 300] @uncertainty=Idev Q: float[300, 300] Idev: float[300, 300] 2-D SAS/WAS images Time: float[nTime] .. _1D SAS data in a time series I(t,Q): .. _1D SAS data in a time series I(t,Q(t)): 1-D :math:I(t,Q(t)) @I_axes="Time,Q" I: float[nTime,100] Q: float[nTime,100] Time: float[nTime] .. _1D SAS data in a time series I(t,Q(t)) +/- Idev(t,Q(t)): 1-D :math:I(t,Q(t))\pm\sigma(t,Q(t)) -------------------------------------------- Now, provide the uncertainties (where Idev represents :math:\sigma(t,Q(t)) ) of the intensities: .. code-block:: text :linenos: SASroot SASentry SASdata @Q_indices=0,1 @I_axes="Time,Q" I: float[nTime,100] @uncertainty=Idev Idev: float[nTime,100] Q: float[nTime,100] Time: float[nTime] .. _representing uncertainty components: Representing Uncertainty Components -------------------------------------- It is possible to represent the components that contribute to the uncertainty by use of a subgroup.  Add a *@components* attribute to the principal uncertainty, naming the subgroup that contains the contributing datasets. As with all uncertainties, each component should have the same *shape* (rank and dimensions) as its parent dataset. Note that a *@basis* attribute indicates how this uncertainty was determined. The values are expected to be a short list, as yet unspecified. .. code-block:: text :linenos: SASroot SASentry SASdata @Q_indices=0 @I_axes=Q Q : float[nI] I : float[nI] @uncertainty=Idev Idev : float[nI] @components=I_uncertainties I_uncertainties: electronic : float[nI] @basis="Johnson noise" counting_statistics: float[nI] @basis="shot noise" secondary_standard: float[nI] @basis="esd" .. _proposed expression of multiple uncertainties: Expression of Multiple Uncertainties (*proposed*) ---------------------------------------------------- .. note::  This is just a proposition.  It is based on the assumption that some analysis method might actually know how to handle this case. If more than one uncertainty contributes to the intensity (and the method described above in :ref:representing uncertainty components is not appropriate), it is proposed to name more than one uncertainty dataset in the *@uncertainty* attribute. The first member in this list would be the principal uncertainty. One example be: .. code-block:: text :linenos: SASroot SASentry SASdata @Q_indices=0 @I_axes=Q Q : float[nI] I : float[nI] @uncertainty=Idev,Ierr Idev : float[nI] Ierr : float[nI] .. TODO: Could make this a note