Matrixmultiplikation: Unterschied zwischen den Versionen

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K (Änderung 23256 von Andreas (Diskussion) wurde rückgängig gemacht.)
Zeile 15: Zeile 15:
 
   {Matrices can only be multiplicated, if the row count of the matrix#1 is the same
 
   {Matrices can only be multiplicated, if the row count of the matrix#1 is the same
 
   as the column of the second matrix:}
 
   as the column of the second matrix:}
   if High(sMatrix) <> (High(Matrix[0])) then
+
   if High(sMatrix[0]) <> High(Matrix) then
 
     Exit;
 
     Exit;
 
   {if a k*l matrix is multiplicated by a m*n matrix,
 
   {if a k*l matrix is multiplicated by a m*n matrix,

Version vom 8. April 2009, 09:59 Uhr

Zur Theorie der Matrixmultiplikation siehe den Matrix Artikel.

Emre lieferte im Forum diesen kleinen Codeschnipsel für die Matrixmultiplikation ab:

Type
  TSMatrix = Array of Array of Single;

//sMatrix := sMatrix * Matrix
procedure pSMatrixMatrixProduct( var sMatrix: TSMatrix; const Matrix: TSMatrix );
var
  m, n,
  o : Integer;
  Res  : TSMatrix;
begin
  {Matrices can only be multiplicated, if the row count of the matrix#1 is the same
  as the column of the second matrix:}
  if High(sMatrix[0]) <> High(Matrix) then
    Exit;
  {if a k*l matrix is multiplicated by a m*n matrix,
   the result matrix will have a k*n dimension:}
  SetLength( Res, Length(sMatrix), Length(Matrix[0]) );
  for m := 0 to High(Res) do
    for n := 0 to High(Res[m]) do
      for o := 0 to High(Matrix) do
        incS( Res[m,n], sMatrix[m,o]*Matrix[o,n] );
  sMatrix := Res;
end;