Fix detrending

src/ArrayFuncs.jl

@@ -36,10 +36,15 @@ end
 detrend(A::AbstractArray{<:Union{Float32,Float64},1}) = (U = deepcopy(A);
  detrend!(U);return U)
 
+"""
+ detrend!(A)
+
+Remove linear trend from columns of `X` using least-squares regression.
+"""
 function detrend!(X::AbstractArray{<:Union{Float32,Float64},2})
  M,N = size(X)
  A = ones(M,2)
- A[:,1] = Array(1:N) ./ N
+ A[:,1] = Array(1:M) ./ M
  for ii = 1:N
  coeff = lstsq(A,X[:,ii])
  X[:,ii] = X[:,ii] .- A *coeff
@@ -52,7 +57,7 @@ detrend(A::AbstractArray{<:Union{Float32,Float64},2}) = (U = deepcopy(A);
 """
  demean!(A)
 
-Remove mean from columns of array `A`.
+Remove mean from array `A`.
 """
 function demean!(A::AbstractArray{<:Union{Float32,Float64},1})
  μ = mean(A)
@@ -64,6 +69,11 @@ end
 demean(A::AbstractArray{<:Union{Float32,Float64},1}) = (U = deepcopy(A);
  demean!(U);return U)
 
+"""
+ demean!(A)
+
+Remove mean from columns of array `A`.
+"""
 function demean!(A::AbstractArray{<:Union{Float32,Float64},2})
  M,N = size(A)
  for ii = 1:N