Commit 6ab068b0 authored by Zolnierczuk, Piotr's avatar Zolnierczuk, Piotr
Browse files

added waveband_binning

parent 7e84e106

pysen/lib.py

+38 −1
Original line number Diff line number Diff line
@@ -3,7 +3,7 @@ PySEN library functions 
"""



#somehow numpy is reporting missing stuff

from numpy import pi, log, sin, arcsin

from numpy import pi, log, sin, arcsin, round



class ElasticScattering(object):

    """Elastic scattering
@@ -113,6 +113,43 @@ def t_binning(lmax, qmin, q0, dq, dlam=3.0, nt=42, trim=False): 
        return max(t1, 1), min(t2, nt)

    return t1, t2



def waveband_binning(nslices, lmin, lmax, t1, t2, nt=42):

    """

    We would like to have constant x = dlam/lambda for N slices for wavelenegth band

        [ lmin=lam[0], lmax=lam[N] ].

    Since

        x = dlam/lambda = 2 * (lam[k] - lam[k-1])/(lam[k] + lam[k-1])

    thus

        lam[k] = lam[k-a] *  (2+x)/(2+x)

    or

        lam[k] = lam[0] * kappa^k

    where

        kappa =  (2+x)/(2+x) = (lam[N]/lam[0])^1/N





    nslices    =  3    # number of slices

    lmin, lmax =  5, 8 # overall wavelength band [A]

    t1,t2      =  4,38 # TOF selection

    nt         =  42   # number of TOF channels

    """

    dlam  = lmax-lmin

    lam_0 = lmax - dlam*(nt-t1)/nt

    lam_N = lmax - dlam*(nt-t2)/nt



    kappa_N = (lam_N/lam_0)**(1.0/nslices)

    x = (2*kappa_N -2 )/(kappa_N +1)



    result = dict(lam0=lam_0, lamN=lam_N, dlam=x, kappa=kappa_N, bands=[])



    l1  = lam_0

    it1 = t1

    for k in range(0,nslices):

        l2  = l1 * kappa_N

        it2 = int( round( nt*(l2 - lmin)/dlam))

        result['bands'].append((l1,l2, it1,it2))

        l1  = l2

        it1 = it2

    return result





get_theta  = ElasticScattering.theta

pysen/revision.py

+3 −3
Original line number Diff line number Diff line
@@ -2,9 +2,9 @@ 
PySEN revision module

"""

import sys

__version__  = "0.33-devel"

__release__  = "20170508"

__date__     = "May 8, 2017"

__version__  = "0.34-devel"

__release__  = "20170518"

__date__     = "May 18, 2017"

#

VERSION  = __version__

RELEASE  = __release__

test/test_lib.py

+24 −1
Original line number Diff line number Diff line
@@ -5,7 +5,8 @@ import unittest 


import numpy as np



from pysen.lib import q_binning, t_binning, get_theta, get_q, get_dspace

from pysen.lib import (q_binning, t_binning, waveband_binning,

                       get_theta, get_q, get_dspace)



class BinningTestCase(unittest.TestCase):

    "Binning Test Cases"
@@ -47,6 +48,28 @@ class BinningTestCase(unittest.TestCase): 
        actual = t_binning(8.0, 0.125, q0, dq, dlam=3.0, nt=42)

        self.assertEqual((t1, t2), actual)



    def test_waveband_binning(self):

        bands = [

            (5.286, 5.810,  4, 11 ),

            (5.810, 6.386, 11, 19 ),

            (6.386, 7.019, 19, 28 ),

            (7.019, 7.714, 28, 38 ),

        ]

        res = waveband_binning(4, 5.0, 8.0, 4, 38, nt=42)

        self.assertEqual(len(bands), len(res['bands']))

        self.assertAlmostEqual(bands[ 0][0], res['lam0'],  3)

        self.assertAlmostEqual(bands[-1][1], res['lamN'],  3)

        self.assertAlmostEqual(1.099, res['kappa'], 3)

        self.assertAlmostEqual(0.094, res['dlam'],  3)

        for i, (l1,l2,t1,t2) in enumerate(res['bands']):

            el1, el2, et1, et2 = bands[i]

            self.assertAlmostEqual(el1, l1, 3)

            self.assertAlmostEqual(el2, l2, 3)

            self.assertEqual(et1, t1)

            self.assertEqual(et2, t2)







class ElasticScatteringCase(unittest.TestCase):

    "Elastic Scattering Test Cases"