Use DataGraphs in ttn_svd and other changes

src/treetensornetworks/opsum_to_ttn/matelem.jl

@@ -1,41 +1,26 @@
 
-#
-# MatElem
-#
-
 struct MatElem{T}
   row::Int
   col::Int
   val::T
 end
 
-#function Base.show(io::IO,m::MatElem)
-#  print(io,"($(m.row),$(m.col),$(m.val))")
-#end
+Base.eltype(::MatElem{T}) where {T} = T
 
-function toMatrix(els::Vector{MatElem{T}})::Matrix{T} where {T}
-  nr = 0
-  nc = 0
-  for el in els
-    nr = max(nr, el.row)
-    nc = max(nc, el.col)
+function col_major_order(el1::MatElem, el2::MatElem)
+  if el1.col == el2.col
+    return el1.row < el2.row
   end
-  M = zeros(T, nr, nc)
+  return el1.col < el2.col
+end
+
+function to_matrix(els::Vector{<:MatElem})
+  els = sort(els; lt=col_major_order)
+  nr = maximum(el -> el.row, els)
+  nc = last(els).col
+  M = zeros(eltype(first(els)), nr, nc)
   for el in els
     M[el.row, el.col] = el.val
   end
   return M
 end
-
-function Base.:(==)(m1::MatElem{T}, m2::MatElem{T})::Bool where {T}
-  return (m1.row == m2.row && m1.col == m2.col && m1.val == m2.val)
-end
-
-function Base.isless(m1::MatElem{T}, m2::MatElem{T})::Bool where {T}
-  if m1.row != m2.row
-    return m1.row < m2.row
-  elseif m1.col != m2.col
-    return m1.col < m2.col
-  end
-  return m1.val < m2.val
-end