Changeset 23df833 in sasmodels


Ignore:
Timestamp:
Oct 30, 2018 6:19:38 PM (13 days ago)
Author:
Paul Kienzle <pkienzle@…>
Branches:
beta_approx, py3, ticket-1015-gpu-mem-error, ticket-1157, ticket-608-user-defined-weights, ticket_1156
Children:
5024a56
Parents:
aa8c6e0
Message:

Document direct call to Fq in user guide

Files:
1 added
3 edited

Legend:

Unmodified
Added
Removed
  • doc/guide/scripting.rst

    rbd7630d r23df833  
    188188python kernel.  Once the kernel is in hand, we can then marshal a set of 
    189189parameters into a :class:`sasmodels.details.CallDetails` object and ship it to 
    190 the kernel using the :func:`sansmodels.direct_model.call_kernel` function.  An 
    191 example should help, *example/cylinder_eval.py*:: 
    192  
    193     from numpy import logspace 
     190the kernel using the :func:`sansmodels.direct_model.call_kernel` function.  To 
     191accesses the underlying $<F(q)>$ and $<F^2(q)>$, use 
     192:func:`sasmodels.direct_model.call_Fq` instead. 
     193 
     194The following example should 
     195help, *example/cylinder_eval.py*:: 
     196 
     197    from numpy import logspace, sqrt 
    194198    from matplotlib import pyplot as plt 
    195199    from sasmodels.core import load_model 
    196     from sasmodels.direct_model import call_kernel 
     200    from sasmodels.direct_model import call_kernel, call_Fq 
    197201 
    198202    model = load_model('cylinder') 
    199203    q = logspace(-3, -1, 200) 
    200204    kernel = model.make_kernel([q]) 
    201     Iq = call_kernel(kernel, dict(radius=200.)) 
    202     plt.loglog(q, Iq) 
     205    pars = {'radius': 200, 'radius_pd': 0.1, 'scale': 2} 
     206    Iq = call_kernel(kernel, pars) 
     207    F, Fsq, Reff, V, Vratio = call_Fq(kernel, pars) 
     208 
     209    plt.loglog(q, Iq, label='2 I(q)') 
     210    plt.loglog(q, F**2/V, label='<F(q)>^2/V') 
     211    plt.loglog(q, Fsq/V, label='<F^2(q)>/V') 
     212    plt.xlabel('q (1/A)') 
     213    plt.ylabel('I(q) (1/cm)') 
     214    plt.title('Cylinder with radius 200.') 
     215    plt.legend() 
    203216    plt.show() 
    204217 
    205 On windows, this can be called from the cmd prompt using sasview as:: 
     218.. figure:: direct_call.png 
     219 
     220    Comparison between $I(q)$, $<F(q)>$ and $<F^2(q)>$ for cylinder model. 
     221 
     222This compares $I(q)$ with $<F(q)>$ and $<F^2(q)>$ for a cylinder 
     223with *radius=200 +/- 20* and *scale=2*. Note that *call_Fq* does not 
     224include scale and background, nor does it normalize by the average volume. 
     225The definition of $F = \rho V \hat F$ scaled by the contrast and 
     226volume, compared to the canonical cylinder $\hat F$, with $\hat F(0) = 1$. 
     227Integrating over polydispersity and orientation, the returned values are 
     228$\sum_{r,w\in N(r_o, r_o/10)} \sum_\theta w F(q,r_o,\theta)\sin\theta$ and 
     229$\sum_{r,w\in N(r_o, r_o/10)} \sum_\theta w F^2(q,r_o,\theta)\sin\theta$. 
     230 
     231On windows, this example can be called from the cmd prompt using sasview as 
     232as the python interpreter:: 
    206233 
    207234    SasViewCom example/cylinder_eval.py 
  • example/cylinder_eval.py

    r2e66ef5 r23df833  
    33""" 
    44 
    5 from numpy import logspace 
     5from numpy import logspace, sqrt 
    66from matplotlib import pyplot as plt 
    77from sasmodels.core import load_model 
    8 from sasmodels.direct_model import call_kernel 
     8from sasmodels.direct_model import call_kernel, call_Fq 
    99 
    1010model = load_model('cylinder') 
    1111q = logspace(-3, -1, 200) 
    1212kernel = model.make_kernel([q]) 
    13 Iq = call_kernel(kernel, dict(radius=200.)) 
    14 plt.loglog(q, Iq) 
     13pars = {'radius': 200, 'radius_pd': 0.1, 'scale': 2} 
     14Iq = call_kernel(kernel, pars) 
     15F, Fsq, Reff, V, Vratio = call_Fq(kernel, pars) 
     16plt.loglog(q, Iq, label='2 I(q)') 
     17plt.loglog(q, F**2/V, label='<F(q)>^2/V') 
     18plt.loglog(q, Fsq/V, label='<F^2(q)>/V') 
    1519plt.xlabel('q (1/A)') 
    16 plt.ylabel('I(q)') 
     20plt.ylabel('I(q) (1/cm)') 
    1721plt.title('Cylinder with radius 200.') 
     22plt.legend() 
    1823plt.show() 
  • sasmodels/direct_model.py

    r304c775 r23df833  
    6767    # type: (Kernel, ParameterSet, float, bool) -> np.ndarray 
    6868    """ 
    69     Like :func:`call_kernel`, but returning F, F^2, R_eff, V, V_form/V_shell. 
     69    Like :func:`call_kernel`, but returning F, F^2, R_eff, V_shell, V_form/V_shell. 
     70 
     71    For solid objects V_shell is equal to V_form and the volume ratio is 1. 
    7072    """ 
    7173    R_eff_type = int(pars.pop('radius_effective_type', 1.0)) 
     
    7678    return calculator.Fq(call_details, values, cutoff, is_magnetic, R_eff_type) 
    7779 
    78 def call_profile(model_info, **pars): 
    79     # type: (ModelInfo, ...) -> Tuple[np.ndarray, np.ndarray, Tuple[str, str]] 
     80def call_profile(model_info, pars=None): 
     81    # type: (ModelInfo, ParameterSet) -> Tuple[np.ndarray, np.ndarray, Tuple[str, str]] 
    8082    """ 
    8183    Returns the profile *x, y, (xlabel, ylabel)* representing the model. 
    8284    """ 
     85    if pars is None: 
     86        pars = {} 
    8387    args = {} 
    8488    for p in model_info.parameters.kernel_parameters: 
     
    377381        Generate a plottable profile. 
    378382        """ 
    379         return call_profile(self.model.info, **pars) 
     383        return call_profile(self.model.info, pars) 
    380384 
    381385def main(): 
Note: See TracChangeset for help on using the changeset viewer.