text: # Copyright 2020 Google LLC
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #      http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  # From "RUNGE-KUTTA METHODS FOR THE STRONG APPROXIMATION OF SOLUTIONS OF STOCHASTIC DIFFERENTIAL EQUATIONS".
  # For additive noise structure.
  # (ODE order, SDE strong order) = (2.0, 1.5).
  
  STAGES = 2
  
  C0 = (0, 3 / 4)
  C1 = (1 / 3, 1)
  
  A0 = (
      (),
      (3 / 4,),
  )
  
  B0 = (
      (),
      (3 / 2,),
  )
  
  alpha = (1 / 3, 2 / 3)
  beta1 = (0, 1)
  beta2 = (-3 / 2, 3 / 2)
  