title: Julia: How do you add/subtract distribution functions?
body: <p>As part of a mini-project where I am numerically solving a linear differential equation, I have to subtract a probability distribution from another distribution. Is there a way to do this in Julia? When I try:</p>
  <pre><code>a = Chi(3) - Uniform(0,1)
  </code></pre>
  <p>There is no method set up for this:</p>
  <pre><code>MethodError: no method matching -(::Chi{Float64}, ::Uniform{Float64})
  Closest candidates are:
    -(::UnivariateDistribution, ::Real) at C:\Users\Acer\.julia\packages\Distributions\Fl5RM\src\univariate\locationscale.jl:139
    -(::ChainRulesCore.AbstractThunk, ::Any) at C:\Users\Acer\.julia\packages\ChainRulesCore\sHMAp\src\tangent_types\thunks.jl:30
    -(::ChainRulesCore.ZeroTangent, ::Any) at C:\Users\Acer\.julia\packages\ChainRulesCore\sHMAp\src\tangent_arithmetic.jl:101
    ...
  </code></pre>