def test_value_set_r1_rit(self):
"""Test of the pipe_control.value.set() function."""
# Set the current data pipe to 'mf'.
pipes.switch('relax_disp')
# Set variables.
exp_type = 'R1rho'
frq = 800.1 * 1E6
# Set an experiment type to the pipe.
set_exp_type(spectrum_id='test', exp_type=exp_type)
# Set a frequency to loop through.
spectrometer.set_frequency(id='test', frq=frq, units='Hz')
# Generate dic key.
r20_key = generate_r20_key(exp_type=exp_type, frq=frq)
# Set first similar to r2.
value.set(val=None, param='r2')
self.assertEqual(cdp.mol[0].res[0].spin[0].r2[r20_key], 10.0)
# Then set for r1.
value.set(val=None, param='r1')
print(cdp.mol[0].res[0].spin[0])
self.assertEqual(cdp.mol[0].res[0].spin[0].r1[r20_key], 2.0)
def test_value_set_r1_rit(self):
"""Test of the pipe_control.value.set() function."""
# Set the current data pipe to 'mf'.
pipes.switch('relax_disp')
# Set variables.
exp_type = 'R1rho'
frq = 800.1 * 1E6
# Set an experiment type to the pipe.
set_exp_type(spectrum_id='test', exp_type=exp_type)
# Set a frequency to loop through.
spectrometer.set_frequency(id='test', frq=frq, units='Hz')
# Generate dic key.
r20_key = generate_r20_key(exp_type=exp_type, frq=frq)
# Set first similar to r2.
value.set(val=None, param='r2')
self.assertEqual(cdp.mol[0].res[0].spin[0].r2[r20_key], 10.0)
# Then set for r1.
value.set(val=None, param='r1')
print(cdp.mol[0].res[0].spin[0])
self.assertEqual(cdp.mol[0].res[0].spin[0].r1[r20_key], 2.0)
def pack_data(ri_id,
ri_type,
frq,
values,
errors,
spin_ids=None,
mol_names=None,
res_nums=None,
res_names=None,
spin_nums=None,
spin_names=None,
spin_id=None,
gen_seq=False,
verbose=True):
"""Pack the relaxation data into the data pipe and spin containers.
The values, errors, and spin_ids arguments must be lists of equal length or None. Each element i corresponds to a unique spin.
@param ri_id: The relaxation data ID string.
@type ri_id: str
@param ri_type: The relaxation data type, ie 'R1', 'R2', or 'NOE'.
@type ri_type: str
@param frq: The spectrometer proton frequency in Hz.
@type frq: float
@keyword values: The relaxation data for each spin.
@type values: None or list of float or float array
@keyword errors: The relaxation data errors for each spin.
@type errors: None or list of float or float array
@keyword spin_ids: The list of spin ID strings. If the other spin identifiers are given, i.e. mol_names, res_nums, res_names, spin_nums, and/or spin_names, then this argument is not necessary.
@type spin_ids: None or list of str
@keyword mol_names: The list of molecule names used for creating the spin IDs (if not given) or for generating the sequence data.
@type mol_names: None or list of str
@keyword res_nums: The list of residue numbers used for creating the spin IDs (if not given) or for generating the sequence data.
@type res_nums: None or list of str
@keyword res_names: The list of residue names used for creating the spin IDs (if not given) or for generating the sequence data.
@type res_names: None or list of str
@keyword spin_nums: The list of spin numbers used for creating the spin IDs (if not given) or for generating the sequence data.
@type spin_nums: None or list of str
@keyword spin_names: The list of spin names used for creating the spin IDs (if not given) or for generating the sequence data.
@type spin_names: None or list of str
@keyword gen_seq: A flag which if True will cause the molecule, residue, and spin sequence data to be generated.
@type gen_seq: bool
@keyword verbose: A flag which if True will cause all relaxation data loaded to be printed out.
@type verbose: bool
"""
# The number of spins.
N = len(values)
# Test the data.
if errors != None and len(errors) != N:
raise RelaxError(
"The length of the errors arg (%s) does not match that of the value arg (%s)."
% (len(errors), N))
if spin_ids and len(spin_ids) != N:
raise RelaxError(
"The length of the spin ID strings arg (%s) does not match that of the value arg (%s)."
% (len(mol_names), N))
if mol_names and len(mol_names) != N:
raise RelaxError(
"The length of the molecule names arg (%s) does not match that of the value arg (%s)."
% (len(mol_names), N))
if res_nums and len(res_nums) != N:
raise RelaxError(
"The length of the residue numbers arg (%s) does not match that of the value arg (%s)."
% (len(res_nums), N))
if res_names and len(res_names) != N:
raise RelaxError(
"The length of the residue names arg (%s) does not match that of the value arg (%s)."
% (len(res_names), N))
if spin_nums and len(spin_nums) != N:
raise RelaxError(
"The length of the spin numbers arg (%s) does not match that of the value arg (%s)."
% (len(spin_nums), N))
if spin_names and len(spin_names) != N:
raise RelaxError(
"The length of the spin names arg (%s) does not match that of the value arg (%s)."
% (len(spin_names), N))
# Generate some empty lists.
if not mol_names:
mol_names = [None] * N
if not res_nums:
res_nums = [None] * N
if not res_names:
res_names = [None] * N
if not spin_nums:
spin_nums = [None] * N
if not spin_names:
spin_names = [None] * N
if errors == None:
errors = [None] * N
# Generate the spin IDs.
if not spin_ids:
spin_ids = []
for i in range(N):
spin_ids.append(
generate_spin_id_unique(spin_num=spin_nums[i],
spin_name=spin_names[i],
res_num=res_nums[i],
res_name=res_names[i],
mol_name=mol_names[i]))
# Initialise the global data for the current pipe if necessary.
if not hasattr(cdp, 'ri_type'):
cdp.ri_type = {}
if not hasattr(cdp, 'ri_ids'):
cdp.ri_ids = []
# Set the spectrometer frequency.
set_frequency(id=ri_id, frq=frq)
# Update the global data.
cdp.ri_ids.append(ri_id)
cdp.ri_type[ri_id] = ri_type
# The selection object.
select_obj = None
if spin_id:
select_obj = Selection(spin_id)
# Loop over the spin data.
data = []
for i in range(N):
# A selection union.
select_id = spin_ids[i]
if spin_id != None:
select_id = "%s&%s" % (select_id, spin_id)
# Get the corresponding spin container.
match_mol_names, match_res_nums, match_res_names, spins = return_spin_from_selection(
selection=select_id, full_info=True, multi=True)
# No spin.
if len(spins) == 0:
continue
# Check that multiple spins are not present.
if len(spins) > 1:
# Generate the list of spin IDs.
new_ids = []
for j in range(len(spins)):
new_ids.append(
generate_spin_id_unique(mol_name=match_mol_names[j],
res_num=match_res_nums[j],
res_name=match_res_names[j],
spin_num=spins[j].num,
spin_name=spins[j].name))
# Raise the error.
raise RelaxMultiSpinIDError(spin_ids[i], new_ids)
# Check that at least one spin is present.
if len(spins) == 0:
raise RelaxNoSpinError(spin_ids[i])
# Loop over the spins.
for j in range(len(spins)):
# No match to the selection.
if select_obj and not select_obj.contains_spin(
spin_num=spins[j].num,
spin_name=spins[j].name,
res_num=res_nums[j],
res_name=res_names[j],
mol=mol_names[j]):
continue
# Initialise the spin data if necessary.
if not hasattr(spins[j], 'ri_data') or spins[j].ri_data == None:
spins[j].ri_data = {}
if not hasattr(spins[j],
'ri_data_err') or spins[j].ri_data_err == None:
spins[j].ri_data_err = {}
# Update all data structures.
spins[j].ri_data[ri_id] = values[i]
spins[j].ri_data_err[ri_id] = errors[i]
# Append the data for printing out.
data.append([spin_ids[i], repr(values[i]), repr(errors[i])])
# Print out.
if verbose:
print(
"\nThe following %s MHz %s relaxation data with the ID '%s' has been loaded into the relax data store:\n"
% (frq / 1e6, ri_type, ri_id))
write_data(out=sys.stdout,
headings=["Spin_ID", "Value", "Error"],
data=data)
def back_calc(ri_id=None, ri_type=None, frq=None):
"""Back calculate the relaxation data.
If no relaxation data currently exists, then the ri_id, ri_type, and frq args are required.
@keyword ri_id: The relaxation data ID string. If not given, all relaxation data will be back calculated.
@type ri_id: None or str
@keyword ri_type: The relaxation data type. This should be one of 'R1', 'R2', or 'NOE'.
@type ri_type: None or str
@keyword frq: The spectrometer proton frequency in Hz.
@type frq: None or float
"""
# Test if the current pipe exists.
check_pipe()
# Test if sequence data is loaded.
if not exists_mol_res_spin_data():
raise RelaxNoSequenceError
# Check that ri_type and frq are supplied if no relaxation data exists.
if ri_id and (not hasattr(cdp, 'ri_ids') or ri_id
not in cdp.ri_ids) and (ri_type == None or frq == None):
raise RelaxError(
"The 'ri_type' and 'frq' arguments must be supplied as no relaxation data corresponding to '%s' exists."
% ri_id)
# Check if the type is valid.
if ri_type and ri_type not in VALID_TYPES:
raise RelaxError("The relaxation data type '%s' must be one of %s." %
(ri_type, VALID_TYPES))
# Frequency checks.
frequency_checks(frq)
# Initialise the global data for the current pipe if necessary.
if not hasattr(cdp, 'ri_type'):
cdp.ri_type = {}
if not hasattr(cdp, 'ri_ids'):
cdp.ri_ids = []
# Update the global data if needed.
if ri_id and ri_id not in cdp.ri_ids:
cdp.ri_ids.append(ri_id)
cdp.ri_type[ri_id] = ri_type
set_frequency(id=ri_id, frq=frq)
# The specific analysis API object.
api = return_api()
# The IDs to loop over.
if ri_id == None:
ri_ids = cdp.ri_ids
else:
ri_ids = [ri_id]
# The data types.
if ri_type == None:
ri_types = cdp.ri_type
else:
ri_types = {ri_id: ri_type}
# The frequencies.
if frq == None:
frqs = cdp.spectrometer_frq
else:
frqs = {ri_id: frq}
# Loop over the spins.
for spin, spin_id in spin_loop(return_id=True):
# Skip deselected spins.
if not spin.select:
continue
# The global index.
spin_index = find_index(spin_id)
# Initialise the spin data if necessary.
if not hasattr(spin, 'ri_data_bc'):
spin.ri_data_bc = {}
# Back-calculate the relaxation value.
for ri_id in ri_ids:
spin.ri_data_bc[ri_id] = api.back_calc_ri(spin_index=spin_index,
ri_id=ri_id,
ri_type=ri_types[ri_id],
frq=frqs[ri_id])
def _load_relax_data(self, spin_line, col, data_set, spin, verbosity=1):
"""Load the relaxation data.
@param spin_line: The line of data for a single spin.
@type spin_line: list of str
@param col: The column indices.
@type col: dict of int
@param data_set: The data set type, one of 'value', 'error', or 'sim_xxx' (where xxx is
a number).
@type data_set: str
@param spin: The spin container.
@type spin: SpinContainer instance
@keyword verbosity: A variable specifying the amount of information to print. The higher
the value, the greater the verbosity.
@type verbosity: int
"""
# Skip the error 'data_set'.
if data_set == 'error':
return
# Relaxation data structures.
ri_labels = eval(spin_line[col['ri_labels']])
remap_table = eval(spin_line[col['remap_table']])
frq_labels = eval(spin_line[col['frq_labels']])
frq = eval(spin_line[col['frq']])
# No relaxation data.
if not ri_labels:
return
# Initialise the value and error arrays.
values = []
errors = []
# Loop over the relaxation data of the residue.
for i in range(len(ri_labels)):
# Determine the data and error columns for this relaxation data set.
data_col = col['frq'] + i + 1
error_col = col['frq'] + len(ri_labels) + i + 1
# Append the value and error.
values.append(eval(spin_line[data_col]))
errors.append(eval(spin_line[error_col]))
# Simulations.
sim = True
if data_set == 'value' or data_set == 'error':
sim = False
# Loop over the relaxation data sets.
for i in range(len(ri_labels)):
# The ID string.
ri_id = "%s_%s" % (ri_labels[i], frq_labels[remap_table[i]])
# Initialise the global structures if necessary.
if not hasattr(cdp, 'ri_ids'):
cdp.ri_ids = []
if not hasattr(cdp, 'ri_type'):
cdp.ri_type = {}
# Update the global structures if necessary.
if ri_id not in cdp.ri_ids:
cdp.ri_ids.append(ri_id)
cdp.ri_type[ri_id] = ri_labels[i]
set_frequency(id=ri_id, frq=frq[remap_table[i]])
# Simulation data.
if sim:
# Initialise.
if not hasattr(spin, 'ri_data_sim'):
spin.ri_data_sim = {}
# Set the value.
spin.ri_data_sim[ri_id] = values[i]
# Normal data.
else:
# Initialise.
if not hasattr(spin, 'ri_data'):
spin.ri_data = {}
if not hasattr(spin, 'ri_data_err'):
spin.ri_data_err = {}
# Set the value.
if values[i] != None:
spin.ri_data[ri_id] = values[i]
if errors[i] != None:
spin.ri_data_err[ri_id] = errors[i]
def load_relax_data(spin_line, col, data_set, spin, verbosity=1):
"""Load the relaxation data.
@param spin_line: The line of data for a single spin.
@type spin_line: list of str
@param col: The column indices.
@type col: dict of int
@param data_set: The data set type, one of 'value', 'error', or 'sim_xxx' (where xxx is
a number).
@type data_set: str
@param spin: The spin container.
@type spin: SpinContainer instance
@keyword verbosity: A variable specifying the amount of information to print. The higher
the value, the greater the verbosity.
@type verbosity: int
"""
# Skip the error 'data_set'.
if data_set == 'error':
return
# Relaxation data structures.
ri_labels = eval(spin_line[col['ri_labels']])
remap_table = eval(spin_line[col['remap_table']])
frq_labels = eval(spin_line[col['frq_labels']])
frq = eval(spin_line[col['frq']])
# No relaxation data.
if not ri_labels:
return
# Initialise the value and error arrays.
values = []
errors = []
# Loop over the relaxation data of the residue.
for i in range(len(ri_labels)):
# Determine the data and error columns for this relaxation data set.
data_col = col['frq'] + i + 1
error_col = col['frq'] + len(ri_labels) + i + 1
# Append the value and error.
values.append(eval(spin_line[data_col]))
errors.append(eval(spin_line[error_col]))
# Simulations.
sim = True
if data_set == 'value' or data_set == 'error':
sim = False
# Loop over the relaxation data sets.
for i in range(len(ri_labels)):
# The ID string.
ri_id = "%s_%s" % (ri_labels[i], frq_labels[remap_table[i]])
# Initialise the global structures if necessary.
if not hasattr(cdp, 'ri_ids'):
cdp.ri_ids = []
if not hasattr(cdp, 'ri_type'):
cdp.ri_type = {}
# Update the global structures if necessary.
if ri_id not in cdp.ri_ids:
cdp.ri_ids.append(ri_id)
cdp.ri_type[ri_id] = ri_labels[i]
set_frequency(id=ri_id, frq=frq[remap_table[i]])
# Simulation data.
if sim:
# Initialise.
if not hasattr(spin, 'ri_data_sim'):
spin.ri_data_sim = {}
# Set the value.
spin.ri_data_sim[ri_id] = values[i]
# Normal data.
else:
# Initialise.
if not hasattr(spin, 'ri_data'):
spin.ri_data = {}
if not hasattr(spin, 'ri_data_err'):
spin.ri_data_err = {}
# Set the value.
if values[i] != None:
spin.ri_data[ri_id] = values[i]
if errors[i] != None:
spin.ri_data_err[ri_id] = errors[i]
def pack_data(ri_id, ri_type, frq, values, errors, spin_ids=None, mol_names=None, res_nums=None, res_names=None, spin_nums=None, spin_names=None, spin_id=None, gen_seq=False, verbose=True):
"""Pack the relaxation data into the data pipe and spin containers.
The values, errors, and spin_ids arguments must be lists of equal length or None. Each element i corresponds to a unique spin.
@param ri_id: The relaxation data ID string.
@type ri_id: str
@param ri_type: The relaxation data type, ie 'R1', 'R2', or 'NOE'.
@type ri_type: str
@param frq: The spectrometer proton frequency in Hz.
@type frq: float
@keyword values: The relaxation data for each spin.
@type values: None or list of float or float array
@keyword errors: The relaxation data errors for each spin.
@type errors: None or list of float or float array
@keyword spin_ids: The list of spin ID strings. If the other spin identifiers are given, i.e. mol_names, res_nums, res_names, spin_nums, and/or spin_names, then this argument is not necessary.
@type spin_ids: None or list of str
@keyword mol_names: The list of molecule names used for creating the spin IDs (if not given) or for generating the sequence data.
@type mol_names: None or list of str
@keyword res_nums: The list of residue numbers used for creating the spin IDs (if not given) or for generating the sequence data.
@type res_nums: None or list of str
@keyword res_names: The list of residue names used for creating the spin IDs (if not given) or for generating the sequence data.
@type res_names: None or list of str
@keyword spin_nums: The list of spin numbers used for creating the spin IDs (if not given) or for generating the sequence data.
@type spin_nums: None or list of str
@keyword spin_names: The list of spin names used for creating the spin IDs (if not given) or for generating the sequence data.
@type spin_names: None or list of str
@keyword gen_seq: A flag which if True will cause the molecule, residue, and spin sequence data to be generated.
@type gen_seq: bool
@keyword verbose: A flag which if True will cause all relaxation data loaded to be printed out.
@type verbose: bool
"""
# The number of spins.
N = len(values)
# Test the data.
if errors != None and len(errors) != N:
raise RelaxError("The length of the errors arg (%s) does not match that of the value arg (%s)." % (len(errors), N))
if spin_ids and len(spin_ids) != N:
raise RelaxError("The length of the spin ID strings arg (%s) does not match that of the value arg (%s)." % (len(mol_names), N))
if mol_names and len(mol_names) != N:
raise RelaxError("The length of the molecule names arg (%s) does not match that of the value arg (%s)." % (len(mol_names), N))
if res_nums and len(res_nums) != N:
raise RelaxError("The length of the residue numbers arg (%s) does not match that of the value arg (%s)." % (len(res_nums), N))
if res_names and len(res_names) != N:
raise RelaxError("The length of the residue names arg (%s) does not match that of the value arg (%s)." % (len(res_names), N))
if spin_nums and len(spin_nums) != N:
raise RelaxError("The length of the spin numbers arg (%s) does not match that of the value arg (%s)." % (len(spin_nums), N))
if spin_names and len(spin_names) != N:
raise RelaxError("The length of the spin names arg (%s) does not match that of the value arg (%s)." % (len(spin_names), N))
# Generate some empty lists.
if not mol_names:
mol_names = [None] * N
if not res_nums:
res_nums = [None] * N
if not res_names:
res_names = [None] * N
if not spin_nums:
spin_nums = [None] * N
if not spin_names:
spin_names = [None] * N
if errors == None:
errors = [None] * N
# Generate the spin IDs.
if not spin_ids:
spin_ids = []
for i in range(N):
spin_ids.append(generate_spin_id_unique(spin_num=spin_nums[i], spin_name=spin_names[i], res_num=res_nums[i], res_name=res_names[i], mol_name=mol_names[i]))
# Initialise the global data for the current pipe if necessary.
if not hasattr(cdp, 'ri_type'):
cdp.ri_type = {}
if not hasattr(cdp, 'ri_ids'):
cdp.ri_ids = []
# Set the spectrometer frequency.
set_frequency(id=ri_id, frq=frq)
# Update the global data.
cdp.ri_ids.append(ri_id)
cdp.ri_type[ri_id] = ri_type
# The selection object.
select_obj = None
if spin_id:
select_obj = Selection(spin_id)
# Loop over the spin data.
data = []
for i in range(N):
# Get the corresponding spin container.
match_mol_names, match_res_nums, match_res_names, spins = return_spin_from_selection(spin_ids[i], full_info=True, multi=True)
if spins in [None, []]:
raise RelaxNoSpinError(spin_ids[i])
# Remove non-matching spins.
if select_obj:
new_spins = []
new_mol_names = []
new_res_nums = []
new_res_names = []
new_ids = []
for j in range(len(spins)):
if select_obj.contains_spin(spin_num=spins[j].num, spin_name=spins[j].name, res_num=match_res_nums[j], res_name=match_res_names[j], mol=match_mol_names[j]):
new_spins.append(spins[j])
new_mol_names.append(match_mol_names[j])
new_res_nums.append(match_res_nums[j])
new_res_names.append(match_res_names[j])
new_ids.append(generate_spin_id_unique(mol_name=mol_names[i], res_num=res_nums[i], res_name=res_names[i], spin_num=spins[j].num, spin_name=spins[j].name))
new_id = new_ids[0]
# Aliases for normal operation.
else:
new_spins = spins
new_mol_names = match_mol_names
new_res_nums = match_res_nums
new_res_names = match_res_names
new_id = spin_ids[i]
new_ids = None
# Check that only a singe spin is present.
if len(new_spins) > 1:
if new_ids:
raise RelaxMultiSpinIDError(spin_ids[i], new_ids)
else:
raise RelaxMultiSpinIDError(spin_ids[i], new_ids)
if len(new_spins) == 0:
raise RelaxNoSpinError(spin_ids[i])
# Loop over the spins.
for j in range(len(new_spins)):
# No match to the selection.
if select_obj and not select_obj.contains_spin(spin_num=new_spins[j].num, spin_name=new_spins[j].name, res_num=new_res_nums[j], res_name=new_res_names[j], mol=new_mol_names[j]):
continue
# Initialise the spin data if necessary.
if not hasattr(new_spins[j], 'ri_data') or new_spins[j].ri_data == None:
new_spins[j].ri_data = {}
if not hasattr(new_spins[j], 'ri_data_err') or new_spins[j].ri_data_err == None:
new_spins[j].ri_data_err = {}
# Update all data structures.
new_spins[j].ri_data[ri_id] = values[i]
new_spins[j].ri_data_err[ri_id] = errors[i]
# Append the data for printing out.
data.append([new_id, repr(values[i]), repr(errors[i])])
# Print out.
if verbose:
print("\nThe following %s MHz %s relaxation data with the ID '%s' has been loaded into the relax data store:\n" % (frq/1e6, ri_type, ri_id))
write_data(out=sys.stdout, headings=["Spin_ID", "Value", "Error"], data=data)
def back_calc(ri_id=None, ri_type=None, frq=None):
"""Back calculate the relaxation data.
If no relaxation data currently exists, then the ri_id, ri_type, and frq args are required.
@keyword ri_id: The relaxation data ID string. If not given, all relaxation data will be back calculated.
@type ri_id: None or str
@keyword ri_type: The relaxation data type. This should be one of 'R1', 'R2', or 'NOE'.
@type ri_type: None or str
@keyword frq: The spectrometer proton frequency in Hz.
@type frq: None or float
"""
# Test if the current pipe exists.
pipes.test()
# Test if sequence data is loaded.
if not exists_mol_res_spin_data():
raise RelaxNoSequenceError
# Check that ri_type and frq are supplied if no relaxation data exists.
if ri_id and (not hasattr(cdp, 'ri_ids') or ri_id not in cdp.ri_ids) and (ri_type == None or frq == None):
raise RelaxError("The 'ri_type' and 'frq' arguments must be supplied as no relaxation data corresponding to '%s' exists." % ri_id)
# Check if the type is valid.
if ri_type and ri_type not in VALID_TYPES:
raise RelaxError("The relaxation data type '%s' must be one of %s." % (ri_type, VALID_TYPES))
# Frequency checks.
frequency_checks(frq)
# Initialise the global data for the current pipe if necessary.
if not hasattr(cdp, 'ri_type'):
cdp.ri_type = {}
if not hasattr(cdp, 'ri_ids'):
cdp.ri_ids = []
# Update the global data if needed.
if ri_id and ri_id not in cdp.ri_ids:
cdp.ri_ids.append(ri_id)
cdp.ri_type[ri_id] = ri_type
set_frequency(id=ri_id, frq=frq)
# Specific Ri back calculate function setup.
back_calculate = specific_analyses.setup.get_specific_fn('back_calc_ri', pipes.get_type())
# The IDs to loop over.
if ri_id == None:
ri_ids = cdp.ri_ids
else:
ri_ids = [ri_id]
# The data types.
if ri_type == None:
ri_types = cdp.ri_type
else:
ri_types = {ri_id: ri_type}
# The frequencies.
if frq == None:
frqs = cdp.spectrometer_frq
else:
frqs = {ri_id: frq}
# Loop over the spins.
for spin, spin_id in spin_loop(return_id=True):
# Skip deselected spins.
if not spin.select:
continue
# The global index.
spin_index = find_index(spin_id)
# Initialise the spin data if necessary.
if not hasattr(spin, 'ri_data_bc'):
spin.ri_data_bc = {}
# Back-calculate the relaxation value.
for ri_id in ri_ids:
spin.ri_data_bc[ri_id] = back_calculate(spin_index=spin_index, ri_id=ri_id, ri_type=ri_types[ri_id], frq=frqs[ri_id])
