Source code for sas.models.PorodModel

""" 
    Provide I(q) = C/q^4,
    Porod function as a BaseComponent model
"""
from sas.models.BaseComponent import BaseComponent
import math

[docs]class PorodModel(BaseComponent): """ Class that evaluates a Porod model. I(q) = scale/q^4 +background """ def __init__(self): """ Initialization """ # Initialize BaseComponent first, then sphere BaseComponent.__init__(self) ## Name of the model self.name = "PorodModel" ## Define parameters self.params = {} self.params['scale'] = 1.0 self.params['background'] = 0.0 self.description = """The Porod model. I(q) = scale/q^4 +background""" ## Parameter details [units, min, max] self.details = {} self.details['scale'] = ['[1/(cm A^4)]', None, None] self.details['background'] = ['[1/cm]', None, None] #list of parameter that cannot be fitted self.fixed = [] def _porod(self, x): """ Evaluate Porod function :param x: q-value """ return self.params['scale']/x**4.0 + self.params['background']
[docs] def run(self, x = 0.0): """ Evaluate the model @param x: input q-value (float or [float, float] as [r, theta]) @return: (porod value) """ if x.__class__.__name__ == 'list': return self._porod(x[0]) elif x.__class__.__name__ == 'tuple': raise ValueError, "Tuples are not allowed as input to models" else: return self._porod(x)
[docs] def runXY(self, x = 0.0): """ Evaluate the model @param x: input q-value (float or [float, float] as [qx, qy]) @return: porod value """ if x.__class__.__name__ == 'list': q = math.sqrt(x[0]**2 + x[1]**2) return self._porod(q) elif x.__class__.__name__ == 'tuple': raise ValueError, "Tuples are not allowed as input to models" else: return self._porod(x)