small fix of docs in all three and a return type in quicsort

diffrax/_solver/align.py

@@ -46,8 +46,9 @@ def __init__(self, beta, a1, b1, aa, chh):
 class ALIGN(AbstractFosterLangevinSRK[_ALIGNCoeffs, _ErrorEstimate]):
     r"""The Adaptive Langevin via Interpolated Gradients and Noise method
     designed by James Foster. This is a second order solver for the
-    Underdamped Langevin Diffusion, the terms for which can be created using
-    [`diffrax.make_underdamped_langevin_term`][]. Uses two evaluations of the vector
+    Underdamped Langevin Diffusion, and accepts terms of the form
+    `MultiTerm(UnderdampedLangevinDriftTerm, UnderdampedLangevinDiffusionTerm)`.
+    Uses two evaluations of the vector
     field per step, but is FSAL, so in practice it only requires one.
 
     ??? cite "Reference"

diffrax/_solver/quicsort.py

@@ -47,9 +47,9 @@ def __init__(self, beta_lr1, a_lr1, b_lr1, a_third, a_div_h):
 class QUICSORT(AbstractFosterLangevinSRK[_QUICSORTCoeffs, None]):
     r"""The QUadrature Inspired and Contractive Shifted ODE with Runge-Kutta Three
     method by James Foster and Daire O'Kane. This is a third order solver for the
-    Underdamped Langevin Diffusion, the terms for which can be created using
-    [`diffrax.make_underdamped_langevin_term`][]. Uses two evaluations of the vector
-    field per step.
+    Underdamped Langevin Diffusion, and accepts terms of the form
+    `MultiTerm(UnderdampedLangevinDriftTerm, UnderdampedLangevinDiffusionTerm)`.
+    Uses two evaluations of the vector field per step.
 
     ??? cite "Reference"
 
@@ -199,7 +199,7 @@ def _compute_step(
         coeffs: _QUICSORTCoeffs,
         rho: UnderdampedLangevinX,
         prev_f: Optional[UnderdampedLangevinX],
-    ) -> tuple[UnderdampedLangevinX, UnderdampedLangevinX, UnderdampedLangevinX, None]:
+    ) -> tuple[UnderdampedLangevinX, UnderdampedLangevinX, None, None]:
         del prev_f
         dtypes = jtu.tree_map(jnp.result_type, x0)
         w: UnderdampedLangevinX = jtu.tree_map(jnp.asarray, levy.W, dtypes)

diffrax/_solver/should.py

@@ -59,8 +59,9 @@ def __init__(self, beta_half, a_half, b_half, beta1, a1, b1, aa, chh, ckk):
 class ShOULD(AbstractFosterLangevinSRK[_ShOULDCoeffs, None]):
     r"""The Shifted-ODE Runge-Kutta Three method
     designed by James Foster. This is a third order solver for the
-    Underdamped Langevin Diffusion, the terms for which can be created using
-    [`diffrax.make_underdamped_langevin_term`][]. Uses three evaluations of the vector
+    Underdamped Langevin Diffusion, the terms of the form
+    `MultiTerm(UnderdampedLangevinDriftTerm, UnderdampedLangevinDiffusionTerm)`.
+    Uses three evaluations of the vector
     field per step, but is FSAL, so in practice it only requires two.
 
     ??? cite "Reference"