value.copy

Synopsis

Copy parameters from one data pipe to another.

Defaults

value.copy(pipe_from=None, pipe_to=None, param=None, force=False)

Keyword arguments

pipe_from: The name of the pipe to copy from.

pipe_to: The name of the pipe to copy to.

param: The parameter to copy. Only one parameter may be selected.

force: A flag which, if set to True, will cause the destination parameter to be overwritten.

Description

If this is used to change values of previously minimised parameters, then the minimisation statistics (chi-squared value, iteration count, function count, gradient count, and Hessian count) will be reset.

Relaxation curve fitting parameters

Please see Table 17.27 on page .

Table 17.27: Relaxation curve fitting parameters.

Name	Description
rx	Either the R1 or R2 relaxation rate
i0	The initial intensity
iinf	The intensity at infinity

Model-free parameters

Please see Table 17.28 on page .

Table 17.28: Model-free parameters.

Name	Description
s2	S2, the model-free generalised order parameter (S2 = S2f.S2s)
s2f	S2f, the faster motion model-free generalised order parameter
s2s	S2s, the slower motion model-free generalised order parameter
local_tm	The spin specific global correlation time (seconds)
te	Single motion effective internal correlation time (seconds)
tf	Faster motion effective internal correlation time (seconds)
ts	Slower motion effective internal correlation time (seconds)
rex	Chemical exchange relaxation (sigma_ex = Rex / omega**2)
csa	Chemical shift anisotropy (unitless)

Setting a parameter value may have no effect depending on which model-free model is chosen. For example if S²_f values and S²_s values are set but the data pipe corresponds to the model-free model `m4' then because these data values are not parameters of the model they will have no effect.

Note that the R_ex values are scaled quadratically with field strength and should be supplied as a field strength independent value. Use the following formula to obtain the correct value:

    value = rex / (2.0 * pi * frequency) ** 2

where:

 rex is the chemical exchange value for the current frequency.

 frequency is the proton frequency corresponding to the data.

Reduced spectral density mapping parameters

Please see Table 17.29 on page .

Table 17.29: Reduced spectral density mapping parameters.

Name	Description
j0	Spectral density value at 0 MHz - J(0)
jwx	Spectral density value at the frequency of the heteronucleus - J(ωX)
jwh	Spectral density value at the frequency of the proton - J(ωH)
csa	Chemical shift anisotropy (unitless)

In reduced spectral density mapping, the CSA value must be set prior to the calculation of spectral density values.

Consistency testing parameters

Please see Table 17.30 on page .

Table 17.30: Consistency testing parameters.

Name	Description
j0	Spectral density value at 0 MHz (from Farrow et al. (1995) JBNMR, 6: 153-162)
f_eta	Eta-test (from Fushman et al. (1998) JACS, 120: 10947-10952)
f_r2	R2-test (from Fushman et al. (1998) JACS, 120: 10947-10952)
csa	Chemical shift anisotropy (unitless)
orientation	Angle between the 15N-1H vector and the principal axis of the 15N chemical shift tensor
tc	The single global correlation time estimate/approximation

In consistency testing, the CSA value, angle Theta (`orientation') and global correlation time must be set prior to the calculation of consistency functions.

N-state model parameters

Please see Table 17.31 on page .

Table 17.31: N-state model parameters.

Name	Description	Type
Axx	The Axx component of the alignment tensor	float
Ayy	The Ayy component of the alignment tensor	float
Axy	The Axy component of the alignment tensor	float
Axz	The Axz component of the alignment tensor	float
Ayz	The Ayz component of the alignment tensor	float
probs	The probabilities of each state	list
alpha	The α Euler angles (for the rotation of each state)	list
beta	The β Euler angles (for the rotation of each state)	list
gamma	The γ Euler angles (for the rotation of each state)	list
paramagnetic_centre	The paramagnetic centre	list

Setting parameters for the N-state model is a little different from the other type of analyses as each state has a set of parameters with the same names as the other states. To set the parameters for a specific state c (ranging from 0 for the first to N-1 for the last, the number c should be given as the index argument. So the Euler angle γ of the third state is specified using the parameter name `gamma' and index of 2.

Relaxation dispersion parameters

Please see Table 17.32 on page .

Table 17.32: Relaxation dispersion parameters.

Name	Description	Type
r2eff	The effective transversal relaxation rate	dict
i0	The initial intensity	dict
r1	The longitudinal relaxation rate	dict
r2	The transversal relaxation rate	dict
r2a	The transversal relaxation rate for state A in the absence of exchange	dict
r2b	The transversal relaxation rate for state B in the absence of exchange	dict
pA	The population for state A	float
pB	The population for state B	float
pC	The population for state C	float
phi_ex	The φ_ex = pA.pB.dw**2 value (ppm^2)	float
phi_ex_B	The fast exchange factor between sites A and B (ppm^2)	float
phi_ex_C	The fast exchange factor between sites A and C (ppm^2)	float
padw2	The pA.dw**2 value (ppm^2)	float
dw	The chemical shift difference between states A and B (in ppm)	float
dw_AB	The chemical shift difference between states A and B for 3-site exchange (in ppm)	float
dw_AC	The chemical shift difference between states A and C for 3-site exchange (in ppm)	float
dw_BC	The chemical shift difference between states B and C for 3-site exchange (in ppm)	float
dwH	The proton chemical shift difference between states A and B (in ppm)	float
dwH_AB	The proton chemical shift difference between states A and B for 3-site exchange (in ppm)	float
dwH_AC	The proton chemical shift difference between states A and C for 3-site exchange (in ppm)	float
dwH_BC	The proton chemical shift difference between states B and C for 3-site exchange (in ppm)	float
kex	The exchange rate	float
kex_AB	The exchange rate between sites A and B for 3-site exchange with kex_AB = k_AB + k_BA (rad.s^-1)	float
kex_AC	The exchange rate between sites A and C for 3-site exchange with kex_AC = k_AC + k_CA (rad.s^-1)	float
kex_BC	The exchange rate between sites B and C for 3-site exchange with kex_BC = k_BC + k_CB (rad.s^-1)	float
kB	Approximate chemical exchange rate constant between sites A and B (rad.s^-1)	float
kC	Approximate chemical exchange rate constant between sites A and C (rad.s^-1)	float
tex	The time of exchange (tex = 1/kex)	float
k_AB	The exchange rate from state A to state B	float
k_BA	The exchange rate from state B to state A	float

Any of the relaxation dispersion parameters which are of the `float' type can be set. Note that setting values for parameters which are not part of the model will have no effect.

Frame order parameters

Please see Table 17.6 on page .

Prompt examples

To copy the CSA values from the data pipe `m1' to `m2', type:

[numbers=none]
relax> value.copy('m1', 'm2', 'csa')