Hi there:
I am trying to solve a complex problem.
I have a Matrix with M values inside. Let?s call it:
Comptes.
Matrix:
Channel Comptes
700 6
701 20
702 5
. .
. .
. .
800 7
M goes from 700 to 820. (length 120)
Well, I need that Summation from c = 700 to 820 of (Comptes_c - Comptes_Gauss_c)^2 = min
Where Comptes_Gauss = A*exp(-(c-Xk)^2/(2s^2))+B*exp(-(c-XL)^2/(2s^2))
(c = Channel)
s = sigma is a constant: 6.3
So I have to find the best suitable values for A, B, Xk and XL in order to minimize the given Summation.
I have initial approximate values to start using Min L/M iteration:
A=250
Xk=750
B=200
XL=775
I have tried to code this:
Code:
Memo1.Clear;
//We have 4 var: A, Xk, B, XLa
N := 4;
SetLength(S, N);
//S: Our initial guess
S[0]:=250; S[1]:=750; S[2]:=200; S[3]:=775;
M := 120;
SetLength(X1, M);
SetLength(Y1, M);
I:=0;
while I<=M-1 do
begin
X1[I] := 700+I;
//We read the 120 values from a memo (mValores)
Y1[I] := strtofloat(mValores.Lines[i]);
Inc(I);
end;
//
// Now S stores starting point, X and Y store points being fitted.
MinLMCreateFJ(N, M, S, State);
MinLMSetCond(State, 0.0, 0.0, 0.001, 0);
while MinLMIteration(State) do
begin
if State.NeedF then
begin
State.F := 0;
end;
I:=0;
while I<=M-1 do
begin
//
// "A" is stored in State.X[0]
// "Xk" - State.X[1]
// "B" - State.X[2]
// "XLa" - State.X[3]
//
FI := Y1[I]-State.X[0]*exp((-1)*((AP_Sqr(X1[I]-State.X[1])/(2*AP_Sqr(6.3)))))-State.X[1]*exp((-1)*((AP_Sqr(X1[I]-State.X[3])/(2*AP_Sqr(6.3)))));
if State.NeedF then
begin
//Summation here?
State.F := State.F+AP_Sqr(FI);
end;
if State.NeedFiJ then
begin
//
// Fi
//
State.Fi[I] := FI;
//
// dFi/dA = -exp^(-((x-Xk)^2)/2s^2)
//
State.J[I,0] := (-1)*exp((-1)*((AP_Sqr(X1[I]-State.X[1])/(2*AP_Sqr(6.3)))));
//
// dFi/dXk = (A*(xK-x)*exp(-(((x-Xk)^2)/(2*s^2))))))/(6.3^2))
//
State.J[I,1] := (State.X[0]*(State.X[1]-X1[I])*exp((-1)*((AP_Sqr(X1[I]-State.X[1])/(2*AP_Sqr(6.3))))))/(AP_Sqr(6.3));
//
// dFi/dB = -exp^(-((x-XL)^2)/2s^2)
//
State.J[I,2] := (-1)*exp((-1)*((AP_Sqr(X1[I]-State.X[3])/(2*AP_Sqr(6.3)))));
//
// dFi/dXLa = (B*(xL-x)*exp(-(((x-xL)^2)/(2*s^2))))))/(6.3^2))
//
State.J[I,3] := (State.X[2]*(State.X[3]-X1[I])*exp((-1)*((AP_Sqr(X1[I]-State.X[3])/(2*AP_Sqr(6.3))))))/(AP_Sqr(6.3));
end;
Inc(I);
end;
end;
MinLMResults(State, S, Rep);
//
// output results
//
Memo1.Lines.Add(Format('A = %4.2f'#13#10'',[
S[0]]));
Memo1.Lines.Add(Format('Xk = %4.2f'#13#10'',[
S[1]]));
Memo1.Lines.Add(Format('B = %4.2f'#13#10'',[
S[2]]));
Memo1.Lines.Add(Format('XLa = %4.2f'#13#10'',[
S[3]]));
Memo1.Lines.Add(Format('TerminationType = %0d (should be 2 - stopping when step is small enough)'#13#10'',[
Rep.TerminationType]));
Excel does a pretty good job with Solver and find the next values:
A=144,58
Xk=755,95
B=278,40
XL=772,68
I have uploaded the excel file I am using where you can see the real values and the used ecuations in a more graphic way.
However, when I use the Delphi implementation, I get wrong values for A, Xk, B, and XL. I don?t know what is wrong (maybe derivatives?)
Thank you in advance.
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