Changeset 7c35fda in sasmodels


Ignore:
Timestamp:
May 31, 2018 10:07:31 AM (3 months ago)
Author:
Adam Washington <adam.washington@…>
Branches:
master, ESS_GUI, beta_approx, beta_approx_lazy_results, beta_approx_new_R_eff, doc_update, ticket-1104-resolution, ticket-1112, ticket-1142-plugin-reload, ticket-1148-Sq-scale-background, ticket-608-user-defined-weights
Children:
befe905
Parents:
84e89cd
Message:

Document reason for change in I(q)

File:
1 edited

Legend:

Unmodified
Added
Removed
  • sasmodels/kernel_iq.c

    r84e89cd r7c35fda  
    8383  in_spin = clip(in_spin, 0.0, 1.0); 
    8484  out_spin = clip(out_spin, 0.0, 1.0); 
    85   // Note: sasview 3.1 scaled all slds by sqrt(weight) and assumed that 
     85  // Previous version of this function took the square root of the weights, 
     86  // under the assumption that  
     87  // 
    8688  //     w*I(q, rho1, rho2, ...) = I(q, sqrt(w)*rho1, sqrt(w)*rho2, ...) 
    87   // which is likely to be the case for simple models. 
     89  // 
     90  // However, since the weights are applied to the final intensity and 
     91  // are not interned inside the I(q) function, we want the full 
     92  // weight and not the square root.  Any function using 
     93  // set_spin_weights as part of calculating an amplitude will need to 
     94  // manually take that square root, but there is currently no such 
     95  // function. 
    8896  weight[0] = (1.0-in_spin) * (1.0-out_spin); // dd 
    8997  weight[1] = (1.0-in_spin) * out_spin;       // du 
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