root_numpy.evaluate

root_numpy.evaluate(obj, array)

Evaluate a ROOT histogram, function, graph, or spline over an array.

Parameters:

obj : TH[1|2|3], TF[1|2|3], TFormula, TGraph, TSpline, or string

A ROOT histogram, function, formula, graph, spline, or string. If a string is specified, a TFormula is created.

array : ndarray

An array containing the values to evaluate the ROOT object on. The shape must match the dimensionality of the ROOT object.

Returns:

y : array

An array containing the values of the ROOT object evaluated at each value in the input array.

Raises:

TypeError

If the ROOT object is not a histogram, function, graph, or spline.

ValueError

If the shape of the array is not compatible with the dimensionality of the ROOT object being evaluated. If the string expression does not compile to a valid TFormula expression.

Examples

>>> from root_numpy import evaluate
>>> from ROOT import TF1, TF2
>>> func = TF1("f1", "x*x")
>>> evaluate(func, [1, 2, 3, 4])
array([  1.,   4.,   9.,  16.])
>>> func = TF2("f2", "x*y")
>>> evaluate(func, [[1, 1], [1, 2], [3, 1]])
array([ 1.,  2.,  3.])
>>> evaluate("x*y", [[1, 1], [1, 2], [3, 1]])
array([ 1.,  2.,  3.])