initialize a dynamic array
I need many 2D Matrices in different dimensions.
I#m working with a dynamic array 2DMatrix_REAL;
How to initialize the dyn. array in an elegant way.
Current solution
setlength(Amatrix, x,y)
Amatrix[0,0] := ..... Amatrix[ ,] := .......
takes millions of lines of code.!
Can I copy the Static array Identity to a Dynamic Array ?
I#m working with a dynamic array 2DMatrix_REAL;
How to initialize the dyn. array in an elegant way.
Current solution
setlength(Amatrix, x,y)
Amatrix[0,0] := ..... Amatrix[ ,] := .......
takes millions of lines of code.!
Can I copy the Static array Identity to a Dynamic Array ?
Identity : array [1..5, 1..5] of Real =
(( 0, 0, 0 , 0 , 0 ) ,
( 0 , 0, 0 , 0 , 0 ) ,
( 0, 0, 1 , 0 , 0 ) ,
( 0 , 0, 0 , 0 , 0 ) ,
( 0 , 0, 0 , 0 , 0 ) );
type 2DMatrix_REAL = array of array of Real;ASKER CERTIFIED SOLUTION
membership
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You have to be careful with that since a dynamic array is actually a pointer.
ASKER
any better solution than this one,
TFilter3D = array [1..3,1..3] of Real;
TFilter4D = array [1..4,1..4] of Real;
TFilter5D = array [1..5,1..5] of Real;
TFilter6D = array [1..6,1..6] of Real;
TFilter7D = array [1..7,1..7] of Real;
const SampleFiler : TFilter3D =
(( 0 , 0.2 , 0 ) ,
( 0.2, 0.2, 0.2 ) ,
( 0 , 0.2 , 0 ));
// copy static array to dyn. array dim =6
procedure LoadDynArrayFromStaticArray ( aFilter : TImageFilterReal; Dim : Integer; aStaticArray : TFilter6D ); overload;
var i,j : Integer;
begin
setlength(AFilter, dim,dim);
for i := 0 to dim -1 do
for j := 0 to dim-1 do
aFilter[i,j] := aStaticArray[i+1,j+1];
end;
// copy static array to dyn. array dim =5
procedure LoadDynArrayFromStaticArray ( aFilter : TImageFilterReal; Dim : Integer; aStaticArray : TFilter5D ); overload;
var i,j : Integer;
begin
setlength(AFilter, dim,dim);
for i := 0 to dim -1 do
for j := 0 to dim-1 do
aFilter[i,j] := aStaticArray[i+1,j+1];
end;
// copy static array to dyn. array dim =4
procedure LoadDynArrayFromStaticArray ( aFilter : TImageFilterReal; Dim : Integer; aStaticArray : TFilter4D ); overload;
var i,j : Integer;
begin
setlength(AFilter, dim,dim);
for i := 0 to dim -1 do
for j := 0 to dim-1 do
aFilter[i,j] := aStaticArray[i+1,j+1];
end;
// copy static array to dyn. array dim =3
procedure LoadDynArrayFromStaticArray ( aFilter : TImageFilterReal; Dim : Integer; aStaticArray : TFilter3D ); overload;
var i,j : Integer;
begin
setlength(AFilter, dim,dim);
for i := 0 to dim -1 do
for j := 0 to dim-1 do
aFilter[i,j] := aStaticArray[i+1,j+1];
end;
procedure LoadImageFilterByIndex( aFilterNameIndex : integer; var aFilter : TImageFilterReal);
var i ,j : Integer;
begin
case aFilterNameIndex of
0: LoadDynArrayFromStaticArray ( aFilter, 3 , BasicBlur );
1: begin
end;
2: begin
end;
3: begin
end;
else
end;
end;
Easiest way is to simply copy the data using move function. see sample:
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
T2dMatrix_REAL = array[1..5, 1..5] of real;
T2DMatrix_Rec = record
Description: string;
Matrix: T2DMatrix_REAL;
end;
TMatrices = array of T2dMatrix_Rec;
const
Identity : T2dMatrix_REAL =
(( 1, 2, 3 , 4 , 5 ) ,
( 6 , 7, 8 , 0 , 10 ) ,
( 11, 12, 13, 14 , 15 ) ,
( 0 , 0, 0 , 0 , 0 ) ,
( 0 , 0, 0 , 0 , 0 ) );
type
TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
Matrices: TMatrices;
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
var c: char;
i: integer;
begin
SetLength(Matrices, 10);
for c:= 'A' to 'J' do
begin
i:= Ord(c) - Ord('A');
Matrices[i].Description:= c+c+c+c+c;
move(identity[1,1], matrices[i].Matrix[1,1], SizeOf(T2dMatrix_REAL));
end;
if (Matrices[1].Matrix[1,1] = 0) then;
end;
end.ASKER
may be Delphi does not offer any more compact solution
From Delphi Help:-
Absolute Addresses
You can create a new variable that resides at the same address as another variable. To do so, put the directive absolute after the type name in the declaration of the new variable, followed by the name of an existing (previously declared) variable. For example,
var
Str: string[32];
StrLen: Byte absolute Str;
specifies that the variable StrLen should start at the same address as Str. Since the first byte of a short string contains the string's length, the value of StrLen is the length of Str.
You cannot initialize a variable in an absolute declaration or combine absolute with any other directives.