Vector.Reverse Method

Overload List

#	Signature	Description
1	function Reverse: TVec;	Reverse vector elements.
	└ indexed: function Reverse(Index: Integer; Len: Integer): TMtxVec;
2	function Reverse(const Vec: TMtxVec): TVec;	Reverse all Vec elements.
	└ indexed: function Reverse(const Vec: TMtxVec; VecIndex: Integer; Index: Integer; Len: Integer): TMtxVec;

Overload 1: function Reverse: TVec;

Reverse vector elements.

Result: stored in self (calling object), returns self for chaining

Remarks:

The method reverses vector elements by using the following equation:

\text{V}[k]=\text{Vec}[N-k],\quad 0\leq k \leq N, \quad \text{where } N=\text{Vec.Length}-1

This overload reverses all calling vector elements in-place.

Examples

var a: Vector;
begin
    a.SetIt(False,[1,2,3,4]);
    a.Reverse;   // a = [4,3,2,1]
end;

var
    a, expected: Vector;
begin
    a := [1.0, 2.0, 3.0, 4.0];
    a.Reverse;
    expected := [4.0, 3.0, 2.0, 1.0];
    if not a.IsEqual(expected, 1e-10, TCompare.cmpAbsolute) then
        raise Exception.Create('Vector.Reverse: mismatch');
end;

See Also: Vector.Rotate, Vector.Shift

Indexed: function Reverse(Index: Integer; Len: Integer): TMtxVec;

Reverses the calling object elements [Index]..[Index+Len-1].

#	Name	Type	Description
1	Index	Integer	start index
2	Len	Integer	element count

Result: stored in self (calling object), returns self for chaining

Remarks:

An exception is raised if array borders are overrun.

Overload 2: function Reverse(const Vec: TMtxVec): TVec;

Reverse all Vec elements.

#	Name	Type	Description
1	Vec	TMtxVec

Result: stored in self (calling object), returns self for chaining

Remarks:

Store the result in the calling vector elements. The Vector.Length and Vector.Complex properties of the calling vector are set implicitly to match Vec vector.

Examples

var
    a, x, expected: Vector;
begin
    x := [1.0, 2.0, 3.0, 4.0];
    a.Reverse(x);
    expected := [4.0, 3.0, 2.0, 1.0];
    if not a.IsEqual(expected, 1e-10, TCompare.cmpAbsolute) then
        raise Exception.Create('Vector.Reverse: mismatch');
end;

Indexed: function Reverse(const Vec: TMtxVec; VecIndex: Integer; Index: Integer; Len: Integer): TMtxVec;

Reverse vector elements.

#	Name	Type	Description
1	Vec	TMtxVec
2	VecIndex	Integer
3	Index	Integer	start index
4	Len	Integer	element count

Result: stored in self (calling object), returns self for chaining

Remarks:

The method reverses Vec vector elements from [VecIndex].. [VecIndex+Len-1] and stores them in the calling vector from [Index]...[Index+Len-1] by using the following equation:

\text{V}[k]=\text{Vec}[N-k],\quad 0\leq k \leq N, \quad \text{where } N=\text{Vec.Length}-1

This overload reverses calling vector elements in-place.

Examples

var a: Vector;
begin
    a.SetIt(False,[1,2,3,4]);
    a.Reverse;   // a = [4,3,2,1]
end;

See Also: Vector.Rotate, Vector.Shift