Hello 🙂
At the beginning: thanks to all of you for many very informative discussions on this forum. When working in D7 in most cases Ctrl+F1 was the right answer to most problems. But now I'm more and more frequently saved by the info provided by members of Delphi-PRAXiS 🙂
And now my actual pain: I'm using Delphi 11 CE ver 28.0. While working with quite simple code I have encountered two strange, fully reproducible problems. The description and related code are below. Additionally all the details and both problems are presented within a short video: https://drive.google.com/file/d/147uSLerfnu-3DZME1jHQ8nsnlAdqtNRi (the code is compiled without optimization). Maybe someone wise can shed some light on the sources of those problems and how to get rid of them (excluding "Embarcadero" problem) ?
All the best!
---------
>>> The example task:
The square matrix TConfusionMatrix = array[0..x,0..x] of Extended is created in two ways (please see the code below):
- with primitive functions such as Cmtx33() or Cmtx22() which place the right values in the right cells of the matrix, or
- by splitting string representation of the matrix (with function MtxStr2ConfusionMatrix). Example string representation of the 3x3 matrix is: '[0,1,2, 3,4,5, 6,7,8]' (rows concatenation, spaces and brackets do not matter).
Created matrices should represent structure "array of rows" and oboth methods should fill the matrix in the same way. For example, if cmtx and cmtx2 are of TConfusionMatrix type then after calls: MtxStr2ConfusionMatrix('[43,0,1,0,45,0,2,0,44]', cmtx, class_cnt); cmtx2:=Cmtx33(43,0,1,0,45,0,2,0,44); variables cmtx and cmtx2 should include the same values in the same elements of matrices (among those which were modified by both functions). Additionally class_cnt will include the size of the row/column of the matrix (in this example class_cnt will be equal 3). It is assumed that strings representing the matrix will always have correct structure and that will include the right number of elements to create a square matrix (so we do not need to think about such things here).
>>> Encountered problems:
1.) The first problem ("the inspection problem"):
Depending on the order of calls to MtxStr2ConfusionMatrix() and Cmtx33() the results of the former function differ.
Sometimes after the call of MtxStr2ConfusionMatrix() the created matrix is displayed in inspection window as it would be (improperly) transposed.
But after next call of Cmtx33() the matrix set by MtxStr2ConfusionMatrix() starts to look properly.
Further comparison of matrices created with both functions indicate that they are equal and related code execution reacts accordingly.
2.) The second problem ("the wtf problem"):
But sometimes - for exactly the same data - the matrix being the result of MtxStr2ConfusionMatrix() permanently stays improperly transposed and the matrices created with both methods are recognised as different. Then this breaks the logic of the code. I'm blind or something but I can't see any obvious reason for such behaviour.
Results from primitive functions Cmtx33(), Cmtx22() are always correct and presented properly.
----------
>>> The code:
const MAX_CLASSES = 50;
type TConfusionMatrix = array[0..MAX_CLASSES,0..MAX_CLASSES] of Extended;
//transforms square matrix in the form of string to a table of rows;
//cmtx_str = '[0,1,2,3,4,5,6,7,8]' => [[0,1,2][3,4,5][6,7,8]]
//(row and column of index=0 are left for other purposes)
function MtxStr2ConfusionMatrix(cmtx_str :String; var cmtx :TConfusionMatrix; var class_cnt :Word) :Boolean;
var i,j :Word;
splittedString : TStringDynArray;
res :Boolean;
begin
res:=True;
try
RemoveChar(cmtx_str,' ');
RemoveChar(cmtx_str,'[');
RemoveChar(cmtx_str,']');
class_cnt:=0;
splittedString:=SplitString(cmtx_str, ',');
if Length(splittedString)<4 then res:=False
else
begin
if Frac(Sqrt(Length(splittedString)))<0.01 then
class_cnt:=Round(Sqrt(Length(splittedString)))
else res:=False;
end;
if class_cnt>=2 then
begin
EraseConfusionMatrix(cmtx,class_cnt,MAX_CLASSES,0);
for i:=1 to class_cnt do
for j:=1 to class_cnt do
cmtx[i,j]:= StrToFloat(splittedString[i+(j-1)*class_cnt - 1]);
end;
except
res:=False;
end;
result:=res;
end;
function CompareConfusionMatrices(c1,c2 :TConfusionMatrix; class_cnt :Word) :Boolean;
var i,j :Integer;
ok :Boolean;
begin
ok:=True;
for i:=1 to class_cnt do
for j:=1 to class_cnt do
if c1[i,j]<>c2[i,j] then
begin
ok:=False;
break;
end;
result:=ok;
end;
function Cmtx33(c11,c12,c13,c21,c22,c23,c31,c32,c33 :LongInt) :TConfusionMatrix;
begin
cmtx[1,1]:=c11;
cmtx[1,2]:=c12;
cmtx[1,3]:=c13;
cmtx[2,1]:=c21;
cmtx[2,2]:=c22;
cmtx[2,3]:=c23;
cmtx[3,1]:=c31;
cmtx[3,2]:=c32;
cmtx[3,3]:=c33;
result:=cmtx;
end;
function Cmtx22(c11,c12,c21,c22 :LongInt) :TConfusionMatrix;
begin
cmtx[1,1]:=c11;
cmtx[1,2]:=c12;
cmtx[2,1]:=c21;
cmtx[2,2]:=c22;
result:=cmtx;
end;
procedure RemoveChar(var s :String; ch :Char);
var d :String;
i,ls :LongInt;
begin
d:='';
ls:=Length(s);
i:=1;
for i:=1 to ls do
if s[i]<>ch then d:=d+s[i];
s:=d;
end;
procedure EraseConfusionMatrix(var cmtx :TConfusionMatrix; num_classes, max_classes :Word; value :Integer);
var i,j :Word;
begin
if num_classes<=max_classes then
begin
for i:=0 to num_classes do
for j:=0 to num_classes do cmtx[i,j]:=value;
end
else ShowMessage('Confusion Matrix can not be greater than '+IntToStr(max_classes)+'x'+IntToStr(max_classes));
end;
===EOT===
![Delphi-PRAXiS [en]](https://en.delphipraxis.net/uploads/monthly_2018_12/logo.png.be76d93fcd709295cb24de51900e5888.png){kind=logo}
