通过rpy2将Python Lambda函数传递给R

Question

我想围绕R库Rdtq（ https://github.com/cran/Rdtq ）编写一个Python包装器。 该库（或更确切地说，类实例）将两个函数作为主要输入：漂移f（x）和扩散g（x）。 例如，

my_drift = function(x) { -x }
my_diff  = function(x) { rep(1,length(x)) }

由于我正在围绕Rdtq类编写包装器，因此我想直接从Python传递漂移和扩散函数，最好是通过lambda函数传递

my_python_drift(x) = lambda x: -x
my_python_diff(x)  = lambda x: np.ones(len(x))

等等。 因此，更笼统地说，我的问题是：是否可以通过rpy2将Python lambda（或全局）函数作为参数传递给R？

Answer 1

考虑使用rpy2的SignatureTranslatedAnonymousPackage（STAP）导入任意R代码作为Python环境中的可用包。 为了演示，下面使用rpy2将用R编写的Rdtq github转换为Python：

[R

# Loading required package: Rdtq
require(Rdtq)

# Assigning drift and diff functions
mydrift = function(x) { -x }
mydiff = function(x) { rep(1,length(x)) }

# Running rdtq()
test = rdtq(h=0.1, k=0.01, bigm=250, init=0, fT=1,
            drift=mydrift, diffusion=mydiff, method="sparse")

# Plotting output
plot(test$xvec, test$pdf, type='l')

蟒蛇

from rpy2 import robjects 
from rpy2.robjects.packages import STAP
from rpy2.robjects.packages import importr

# Loading required package: Rdtq
Rdtq = importr('Rdtq')

fct_string = """
my_drift <- function(x) { -x }
my_diff  <- function(x) { rep(1,length(x)) }
"""

# Creating package with above drift and diff methods
my_fcts = STAP(fct_string, "my_fcts")

# Running rdtq() --notice per Python's model: all methods are period qualified
test = Rdtq.rdtq(h=0.1, k=0.01, bigm=250, init=0, fT=1,
                 drift=my_fcts.my_drift(), diffusion=my_fcts.my_diff(), method="sparse")

# Load plot function
plot = robjects.r.plot

# Plotting by name index
plot(test[test.names.index('xvec')], test[test.names.index('pdf')], type='l')