Source code for pyne.dbgen.scattering_lengths

"""This module provides a way to grab and store raw data for neutron scattering 
lengths.  This data comes from Neutron News, Vol. 3, No. 3, 1992, pp. 29-37 via 
a NIST webpage (  Please
contact Alan Munter, <> for more information."""
from __future__ import print_function
import os
import re
import shutil
from pyne.utils import QA_warn

    import urllib.request as urllib2
except ImportError:
    import urllib2

import numpy as np
import tables as tb

from .. import nucname
from .api import BASIC_FILTERS


[docs]def grab_scattering_lengths(build_dir="", file_out='scattering_lengths.html'): """Grabs the scattering cross-section lengths for neutrons from the NIST website or locally from this module.""" build_filename = os.path.join(build_dir, file_out) local_filename = os.path.join(os.path.split(__file__)[0], file_out) if os.path.exists(local_filename): shutil.copy(local_filename, build_filename) return nist = urllib2.urlopen("") with open(build_filename, 'w') as f: f.write(
[docs]def nist_num(nist_data): """Converts a NIST style data point to a point. Parameters ---------- nist_data : str A nist data point. Returns ------- d : float or complex a data point. """ nd = nist_data while ('(' in nd) or (')' in nd): nd_pre = nd.partition('(') nd_post = nd.partition(')') nd = nd_pre[0] + nd_post[2] if (nd == "---") or (nd == ""): nd = "0.0" nd = nd.replace("<i>i</i>", 'j') d = eval(nd) return d
sl_dtype = np.dtype([ ('nuc', int), ('b_coherent', np.complex128), ('b_incoherent', np.complex128), ('xs_coherent', float), ('xs_incoherent', float), ('xs', float), ]) scat_len_data = "[ aeE()<>i/.+\d-]+?" scat_len_space = "[ \t]+" scat_len_pattern = "<td>{space}(?P<iso>[A-Za-z\d]+){space}<td>{space}(?P<conc>{data}){space}<td>{space}(?P<b_coherent>{data}){space}<td>{space}(?P<b_incoherent>{data}){space}<td>{space}(?P<xs_coherent>{data}){space}<td>{space}(?P<xs_incoherent>{data}){space}<td>{space}(?P<xs>{data}){space}<td>{space}(?P<xs_a>{data}){space}<tr>".format(data=scat_len_data, space=scat_len_space)
[docs]def parse_scattering_lengths(build_dir): """Converts to scattering lenth data to a numpy array.""" build_filename = os.path.join(build_dir, "scattering_lengths.html") # Read in cinder data file with open(build_filename, 'r') as f: raw_data = sl_data = [] # Iterate over all isotopes in the table for m in re.finditer(scat_len_pattern, raw_data): md = m.groupdict() slrow = (['iso']), nist_num(md['b_coherent']) * (1E-13), nist_num(md['b_incoherent']) * (1E-13), nist_num(md['xs_coherent']), nist_num(md['xs_incoherent']), nist_num(md['xs'])) sl_data.append(slrow) sl_array = np.array(sl_data, dtype=sl_dtype) return sl_array
[docs]def make_scattering_lengths_table(nuc_data, build_dir=""): """Adds the neutron sacttering lengths to the nuc_data library. Parameters ---------- nuc_data : str Path to nuclide data file. build_dir : str Directory to place html files in. """ sl_array = parse_scattering_lengths(build_dir) # Open the HDF5 File db = tb.open_file(nuc_data, 'a', filters=BASIC_FILTERS) # Ensure that the appropriate file structure is present if not hasattr(db.root, 'neutron'): # Create neutron group neutron_group = db.create_group('/', 'neutron', 'Neutron Data') # Init the neutron fission product info table sl_table = db.create_table('/neutron/', 'scattering_lengths', np.empty(0, dtype=sl_dtype), 'Neutron Scattering Lengths, b [cm], sigma [barns]', expectedrows=len(sl_array)) sl_table.append(sl_array) # Write the table sl_table.flush() # Close the hdf5 file db.close()
[docs]def make_scattering_lengths(args): """Controller function for adding scattering lengths.""" nuc_data, build_dir = args.nuc_data, args.build_dir # Check that the table exists with tb.open_file(nuc_data, 'a', filters=BASIC_FILTERS) as f: if hasattr(f.root, 'neutron') and hasattr(f.root.neutron, 'scattering_lengths'): print("skipping scattering lengths data table creation; already exists.") return # Grab the raw data print("Grabbing the scattering length data.") grab_scattering_lengths(build_dir) # Make scatering table once we have the data print("Making neutron scattering length table.") make_scattering_lengths_table(nuc_data, build_dir)