allocate less in limited sparse printing

iterate and print in forwards order instead of saving to an array and reversing
use searchsortedfirst to find which column to start in

fix tests for 32 bit

base/sparse/sparsematrix.jl

@@ -149,7 +149,7 @@ function Base.show(io::IOContext, S::SparseMatrixCSC)
 
  function _format_line(r, col)
  pad = ndigits(max(S.m, S.n))
- print(ioc, " ", '[', rpad(S.rowval[r], pad), ", ", lpad(col, pad), "] = ")
+ print(ioc, " [", rpad(S.rowval[r], pad), ", ", lpad(col, pad), "] = ")
  if isassigned(S.nzval, Int(r))
  show(ioc, S.nzval[r])
  else
@@ -171,19 +171,17 @@ function Base.show(io::IOContext, S::SparseMatrixCSC)
  count == print_count && break
  end
 
- lines_bottom = String[]
  if !will_fit
- count = 0
- for col = reverse(1:S.n), r = reverse(nzrange(S, col))
- count += 1
- push!(lines_bottom, _format_line(r, col))
- count == print_count && break
+ print(io, "\n \u22ee")
+ # find the column to start printing in for the last print_count elements
+ nextcol = searchsortedfirst(S.colptr, nnz(S) - print_count + 1)
+ for r = nnz(S) - print_count + 1 : S.colptr[nextcol] - 1
+ print(io, "\n", _format_line(r, nextcol - 1))
+ end
+ # print all of the remaining columns
+ for col = nextcol:S.n, r = nzrange(S, col)
+ print(io, "\n", _format_line(r, col))
  end
- end
-
- if !will_fit
- print(io, "\n ", '\u22ee', "\n")
- print(io, join(reverse(lines_bottom), '\n'))
  end
 end
 

test/sparse/sparse.jl

@@ -1790,7 +1790,7 @@ end
  " = 1.0\n ⋮\n [5, 3] = 5.0")
 
  show(ioc, MIME"text/plain"(), sparse(ones(5,3)))
- @test String(take!(io)) == string("5×3 SparseMatrixCSC{Float64,Int64} with 15 stored entries:\n [1, 1]",
+ @test String(take!(io)) == string("5×3 SparseMatrixCSC{Float64,$Int} with 15 stored entries:\n [1, 1]",
  " = 1.0\n ⋮\n [5, 3] = 1.0")
 
  # odd number of rows
@@ -1804,7 +1804,7 @@ end
  " = 1.0\n [2, 1] = 2.0\n ⋮\n [5, 3] = 5.0\n [6, 3] = 6.0")
 
  show(ioc, MIME"text/plain"(), sparse(ones(6,3)))
- @test String(take!(io)) == string("6×3 SparseMatrixCSC{Float64,Int64} with 18 stored entries:\n [1, 1]",
+ @test String(take!(io)) == string("6×3 SparseMatrixCSC{Float64,$Int} with 18 stored entries:\n [1, 1]",
  " = 1.0\n [2, 1] = 1.0\n ⋮\n [5, 3] = 1.0\n [6, 3] = 1.0")
 
  ioc = IOContext(io, :displaysize => (9, 80))