arrays - Julia 中以 DataArrays 和 Arrays 作为参数的函数

Question

我想编写一个可以在 Julia 中同时使用 DataArray 和标准数组的函数。实际上，我想编写一个函数的方法——一种采用两个类似向量的结构作为参数，另一种采用两个类似矩阵的参数。

由于数组和 DataArray 基本相同，只是 DataArray 允许 NA 值，所以我真的不想为每个函数编写 4 个版本，只是为了合并 Array 和 DataArray 参数的所有不同组合。现在，我使用以下六个(!)函数来实现我的目标:

function covar_to_intensity{T<:Number}(covariates::Array{T, 1}, coefficients::Array{T, 1})
  try
    return(exp(covariates' * coefficients)[1])
  catch
    error("Multiplication of covariates and coefficients not possible.")
  end
end

function covar_to_intensity{T<:Number}(covariates::Array{T, 2}, coefficients::Array{T, 2})
  try
    return(exp(covariates * coefficients))
  catch
    error("Multiplication of covariates and coefficients not possible.")
  end
end

function covar_to_intensity{T<:Number}(covariates::DataArray{T, 1}, coefficients::DataArray{T, 1})
  try
    return(exp(covariates' * coefficients)[1])
  catch
    error("Multiplication of covariates and coefficients not possible.")
  end
end

function covar_to_intensity{T<:Number}(covariates::DataArray{T, 2}, coefficients::DataArray{T, 2})
  try
    return(exp(covariates * coefficients))
  catch
    error("Multiplication of covariates and coefficients not possible.")
  end
end

function covar_to_intensity{T<:Number}(covariates::Array{T, 1}, coefficients::DataArray{T, 1})
  try
    return(exp(covariates' * coefficients)[1])
  catch
    error("Multiplication of covariates and coefficients not possible.")
  end
end

function covar_to_intensity{T<:Number}(covariates::Array{T, 2}, coefficients::DataArray{T, 2})
  try
    return(exp(covariates * coefficients))
  catch
    error("Multiplication of covariates and coefficients not possible.")
  end
end

我知道这可能是计算这些乘积的低效方法，但我对如何编写同时采用数组和 DataArray 的函数也很感兴趣。

谢谢!

Answer 1

一般来说，您可以为AbstractArray定义方法:

function covar_to_intensity{T<:Number}(covariates::AbstractVector{T}, coefficients::AbstractVector{T})
  try
     return exp(covariates * coefficients)
  catch
    error("Multiplication of covariates and coefficients not possible.")
   end
end

function covar_to_intensity{T<:Number}(covariates::AbstractMatrix{T}, coefficients::AbstractMatrix{T})
  try
     return exp((covariates' * coefficients)[1])
  catch
    error("Multiplication of covariates and coefficients not possible.")
   end
end