update comments

desc/compute/_fast_ion.py

@@ -88,6 +88,11 @@ def _drift2(data, B, pitch):
 def _Gamma_c(params, transforms, profiles, data, **kwargs):
     """Fast ion confinement proxy as defined by Nemov et al.
 
+    Notes
+    -----
+    A much more performant version is available at https://github.com/unalmis/DESC.
+    The reference 2 below refers to that implementation.
+
     [1] Poloidal motion of trapped particle orbits in real-space coordinates.
         V. V. Nemov, S. V. Kasilov, W. Kernbichler, G. O. Leitold.
         Phys. Plasmas 1 May 2008; 15 (5): 052501.
@@ -362,6 +367,11 @@ def gamma_c0(data):
 def _Gamma_c_Velasco(params, transforms, profiles, data, **kwargs):
     """Fast ion confinement proxy as defined by Velasco et al.
 
+    Notes
+    -----
+    A much more performant version is available at https://github.com/unalmis/DESC.
+    The reference 2 below refers to that implementation.
+
     [1] A model for the fast evaluation of prompt losses of energetic ions in
         stellarators. Equation 16.
         J.L. Velasco et al. 2021 Nucl. Fusion 61 116059.

desc/compute/_neoclassical.py

@@ -183,6 +183,11 @@ def _dI_2(data, B, pitch):
 def _epsilon_32(params, transforms, profiles, data, **kwargs):
     """Effective ripple modulation amplitude to 3/2 power.
 
+    Notes
+    -----
+    A much more performant version is available at https://github.com/unalmis/DESC.
+    The reference 2 below refers to that implementation.
+
     [1] Evaluation of 1/ν neoclassical transport in stellarators.
         V. V. Nemov, S. V. Kasilov, W. Kernbichler, M. F. Heyn.
         Phys. Plasmas 1 December 1999; 6 (12): 4622–4632.

desc/integrals/bounce_integral.py

@@ -166,6 +166,11 @@ class Bounce2D(Bounce):
     the particle's guiding center trajectory traveling in the direction of increasing
     field-line-following coordinate ζ.
 
+    Notes
+    -----
+    A much more performant version is available at https://github.com/unalmis/DESC.
+    The reference 2 below refers to that implementation.
+
     Refrences
     ---------
     Spectrally accurate, reverse-mode differentiable bounce-averaging algorithm

desc/objectives/_fast_ion.py

@@ -33,6 +33,11 @@ class GammaC(_Objective):
     The radial electric field has a negligible effect, since fast particles
     have high energy with collisionless orbits, so it is assumed to be zero.
 
+    Notes
+    -----
+    A much more performant version is available at https://github.com/unalmis/DESC.
+    The reference 3 below refers to that implementation.
+
     References
     ----------
     [1] Poloidal motion of trapped particle orbits in real-space coordinates.

desc/objectives/_neoclassical.py

@@ -23,6 +23,11 @@ class EffectiveRipple(_Objective):
     coefficients in the banana regime. To ensure low neoclassical transport,
     a stellarator is typically optimized so that ε < 0.02.
 
+    Notes
+    -----
+    A much more performant version is available at https://github.com/unalmis/DESC.
+    The reference 2 below refers to that implementation.
+
     References
     ----------
     [1] Evaluation of 1/ν neoclassical transport in stellarators.