setup do
        
  # create a = [20 30 40 50]
  @a = MDArray.arange(20, 60, 10)
  # create b = [0 1 2 3]
  @b = MDArray.arange(4)
  # create c = [1.87 5.34 7.18 8.84]
  @c = MDArray.double([4], [1.87, 5.34, 7.18, 8.84])
  # create d = [[1 2] [3 4]]
  @d = MDArray.int([2, 2], [1, 2, 3, 4])
  # creates an array from a function (actually a block).  The name fromfunction
  # is preserved to maintain API compatibility with NumPy (is it necessary?)
  @e = MDArray.fromfunction("double", [4, 5, 6]) do |x, y, z|
    3.21 * (x + y + z)
  end
  @f = MDArray.fromfunction("double", [4, 5, 6]) do |x, y, z|
    9.57 * x + y + z
  end
  @g = MDArray.byte([1], [60])
  @h = MDArray.byte([1], [13])
  @i = MDArray.double([4], [2.0, 6.0, 5.0, 9.0])
end # setup
#-------------------------------------------------------------------------------------
#
#-------------------------------------------------------------------------------------
should "allow setting values" do
  a = MDArray.int([5, 3, 5])
  a.fill(10)
end
#-------------------------------------------------------------------------------------
#
#-------------------------------------------------------------------------------------
should "do basic array operations" do
  # c = [20 31 42 53]
  # chage the way operators work by changing the binary_operator parameter.
  # @a.binary_operator = BinaryOperator
  c = @a + @b
  assert_equal(20, c[0])
  # c = [20 29 38 47]
  c = @a - @b
  assert_equal(38, c[2])
  # c = [0 30 80 100]
  c = @a * @b
  assert_equal(150, c[3])
  # c = [0 0 0 0]
  c = @b / @a
  assert_equal(0, c[1])
  
  # c = [1 30 1600 125000]
  c = @a ** @b
  assert_equal(1600, c[2])
  # although a and d have the same number of elements we cannot do arithmetic
  # with them.
  assert_raise ( RuntimeError ) { c = @a + @d }
  # arrays a and b still have the same values as before
  assert_equal(20, @a[0])
  assert_equal(30, @a[1])
  assert_equal(2, @b[2])
  assert_equal(3, @b[3])
  # adding two double arrays
  result = @e + @f
  assert_equal(result[0, 0, 0], @e[0, 0, 0] + @f[0, 0, 0])
  # request that result to be of type "byte" is respected
  c = @a.add(@b, "byte")
  assert_equal("byte", c.type)
  # normal int type for result
  c = @a.add 10
  assert_equal("int", c.type)
  # upcast will be enforced.  result is double
  c = @a.add @c
  assert_equal("double", c.type)
end
#-------------------------------------------------------------------------------------
# Array operations are done elementwise
#-------------------------------------------------------------------------------------
should "do basic operations with numbers" do
  # elementwise operation
  c = @a + 20
  assert_equal("40 50 60 70 ", c.to_string)
  # Power test
  c = @c ** 2.5
  assert_equal("4.781938829669405 65.89510321368653 138.13734690718798 232.3435723800906 ",
               c.to_string)
end
#-------------------------------------------------------------------------------------
#
#-------------------------------------------------------------------------------------
should "do in-place operations" do
  # a = [20 30 40 50]
  # a ^ 2 = [400, 900, 1600, 2500]
  @a.mul! @a
  assert_equal(1600, @a[2])
  @a.add! 5
  assert_equal("405 905 1605 2505 ", @a.to_string)
  # do in place operations
  # a = a + b = [405 906 1607 2508]
  @a.add! @b
  assert_equal(906, @a[1])
  assert_equal(2508, @a[3])
end
#-------------------------------------------------------------------------------------
#
#-------------------------------------------------------------------------------------
should "work with expressions" do
  result = @a + 2 * @b - @c
  assert_equal("18.13 26.66 36.82 47.16 ", result.to_string)
  result = (@a + 2) * @b - @c
  assert_equal("-1.87 26.66 76.82 147.16 ", result.to_string)
  result = (@a + 2) * (@b - @c)
  assert_equal("-41.14 -138.88 -217.56 -303.68 ", result.to_string)
end
#-------------------------------------------------------------------------------------
#
#-------------------------------------------------------------------------------------
should "do bitwise operations" do
  result = @g & @h
  assert_equal("12 ", result.to_string)
  result = @g | @h
  assert_equal("61 ", result.to_string)
  result = @g ^ @h
  assert_equal("49 ", result.to_string)
  # result = @g.binary_ones_complement(@h)
  # assert_equal("-60 ", result.to_string)
  result = @g << 2
  assert_equal("240 ", result.to_string)
  result = @g >> 2
  assert_equal("15 ", result.to_string)
  result = @g & 13
  # although we can coerce arithmetic operations we cannot coerce bitwise operations
  assert_raise ( TypeError ) { result = 13 & @g }
end
#-------------------------------------------------------------------------------------
#
#-------------------------------------------------------------------------------------
should "coerce arithmetic operations" do
  # resulting array c is upcasted to double.  Note that the operation is commutative
  c = 20.5 + @a
  assert_equal("40.5 50.5 60.5 70.5 ", c.to_string)
  assert_equal(c.type, "double")
  # Can also operate with the number first.  Still doing elementwise operation
  # @c = MDArray.double([4], [1.87, 5.34, 7.18, 8.84])
  c = 10 / @c
  assert_equal("5.347593582887701 1.8726591760299627 1.392757660167131 1.1312217194570136 ",
               c.to_string)
  # Works with subtraction
  c = 0.5 - @a
  assert_equal("-19.5 -29.5 -39.5 -49.5 ", c.to_string)
  # *TODO: 2.5 ** @a is not working... seems to be a bug, since everything else works
  # fine. Open a case after trying to make a simpler example.
  # c = 2.5 ** @a
end
#-------------------------------------------------------------------------------------
#
#-------------------------------------------------------------------------------------
should "work with unary operators" do
  result = @c.ceil
  assert_equal(result.to_string, "2.0 6.0 8.0 9.0 ")
  result = result / 4.254
  assert_equal(result.to_string, "0.47014574518100616 1.4104372355430186 1.8805829807240246 2.1156558533145278 ")
  result.floor!
  assert_equal("0.0 1.0 1.0 2.0 ", result.to_string)
  @c.ceil!
  assert_equal("2.0 6.0 8.0 9.0 ", @c.to_string)
end
#------------------------------------------------------------------------------------
#
#------------------------------------------------------------------------------------
should "allow users operator's creation" do
  
  # creating a binary_op as it takes two MDArrays as arguments.  The method "total_sum"
  # will make a cumulative sum of all sums of array1[i] + array2[i].  To achieve this
  # we state that the result is "reduce" (just a number) and that the operation
  # perfomed is the proc given that sums (sum, val1, val2).  The initial value of sum 
  # is given by the second proc Proc.new { 0 }.  This binary operator is defined 
  # for "int" MDArrays and all "lower" classes, i.e., short, byte.
  UserFunction.binary_operator("total_sum", "reduce",
                               Proc.new { |sum, val1, val2| sum + val1 + val2 }, 
                               "int", nil, Proc.new { 0 })
  c = @a.total_sum(@b)
  assert_equal(146, c)
  c = @a.total_sum(@c)
  assert_equal(163.23000000000002, c)
  c = @g.total_sum(@h)
  assert_equal(73, c)
  # total_sum is not defined for double MDArray
  assert_raise ( NoMethodError ) { c = @c.total_sum(@b) }
  # define inner_product for the whole hierarchy as it defines it for double
  UserFunction.binary_operator("inner_product", "reduce", 
                               Proc.new { |sum, val1, val2| sum + (val1 * val2) }, 
                               "double", nil, Proc.new { 0 })
  c = @a.inner_product(@b)
  assert_equal(260, c)
  c = @a.inner_product(@c)
  assert_equal(926.8, c)
  c = @e.inner_product(@f)
  assert_equal(50079.530999999995, c)
  # same as the inner product but multiplies all values.  Note that in this case
  # we need to initialize prod with value 1, which is done with the second Proc
  UserFunction.binary_operator("proc_proc", "reduce", 
                               Proc.new { |prod, val1, val2| prod * (val1 * val2) }, 
                               "double", nil, Proc.new { 1 })
  c = @a.proc_proc(@b)
  assert_equal(0, c)
  c = @a.proc_proc(@c)
  assert_equal(760_572_850.7_520_001, c)
  # Possible to create a new binary operator and force the final type of the resulting
  # MDArray.  Bellow, whenever addd is used the resulting array will be of type double
  func = MDArray.select_function("add")
  UserFunction.binary_operator("addd", "default", func, "double", "double")
  
  # @a and @b are int arrays, so result should be int, but since addd is used, resulting
  # array will be double
  c = @a.addd(@b)
  assert_equal("double", c.type)
  c.print
  # request that resulting array of type int is ignored when using addd
  c = @a.addd(@b, "int")
  assert_equal("double", c.type)

  MDArray.make_binary_operators("perc_inc", 
                                Proc.new { |val1, val2| (val2 - val1) / val1 })
  result = @c.perc_inc @i
  assert_equal("0.06951871657754005 0.12359550561797755 -0.3036211699164345 0.018099547511312233 ", result.to_string)
  # do it in place
  # "0.06951871514320374 0.1235954761505127 -0.3036211431026459 0.018099529668688774 "
  # @c.binary_operator = FastBinaryOperator
  # @c.binary_operator = BinaryOperator
  @c.perc_inc! @i
  assert_equal("0.06951871657754005 0.12359550561797755 -0.3036211699164345 0.018099547511312233 ", @c.to_string)

end