The ScalarQuantity class encapsulates data from scalar quantities in DREAM output, i.e. data which only has a single, scalar value at a given time. Scalar quantities only evolve in time. Examples of scalar quantities found in DREAM are the total plasma current I_p and the poloidal flux on the tokamak wall psi_edge.


s1 = ScalarQuantity(name='MyScalarQuantity', data=[1,2,3], grid=grid, output=do)
s2 = ScalarQuantity(name='MyScalarQuantity', data=[4,5,6], grid=grid, output=do)

As with any UnknownQuantity, a ScalarQuantity can be part of an arithmetic expression with another ScalarQuantity:

s3 = s1 + s2
s4 = s1 - s2
s5 = s1 * s2
s6 = s1 / s2

Operations are element-wise.

It is also possible to easily plot a ScalarQuantity by calling the plot() member method:


If desired, a selection of time points for which to plot the quantity can be specified to plot():


Class definition

class DREAM.Output.ScalarQuantity.ScalarQuantity(name, data, grid, output, attr=[])

Bases: DREAM.Output.UnknownQuantity.UnknownQuantity


Direct access to data.

__init__(name, data, grid, output, attr=[])


  • name (str) – Name of quantity.

  • data (numpy.ndarray) – Data for quanity.

  • attr (list) – List of attributes for quantity.

  • grid – Grid on which the quantity is defined.

  • output (DREAMOutput) – Parent output object.


Dumps the data of this quantity as a string.


t – Selection of time points to dump.

plot(ax=None, show=None, t=None)

Generate a plot of the time evolution of this quantity.

  • ax (matplotlib.axes.Axes) – Axes object to create the plot on.

  • show (bool) – If True, calls after creating the plot.

  • t – Selection of time points to plot. Can be a list, numpy array, slice or None.


Print the data in this quantity at the given time.


t – Time, or selection of times, from which to print the data.