“…Letting the skewness parameter θ = 0, one gets C − (α, θ = 0) = C + (α, θ = 0) = 1 2 cos π 2 α , α = 1, which is just the Riesz derivative (1). For most fractional differential equations, to obtain the analytical solutions are not easy even impossible, so many researchers have to solve fractional differential equations by using various kinds of numerical methods [1,6,7,10,11,28,29,30,31,32,33,34]. In particular, as for Riesz spatial fractional differential equations, the key issue is how to approximate the Riesz derivatives.…”