Threaded Mode | Linear Mode

Eddie W. Shore · 04-17-2016, 07:44 PM

Link: http://edspi31415.blogspot.com/2016/04/h...model.html

The program GOMPERTZ fits data {y_1, y_2, y_3, ..., y_m} to the curve y = a * b^c^x

Program:

Code:

EXPORT GOMPERTZ(yl)

BEGIN

LOCAL y,m,n;

// 2nd STEP

y:=SORT(yl);

m:=SIZE(y);

n:=m/3;

LOCAL y1:=SUB(y,1,n);

LOCAL y2:=SUB(y,n+1,2*n);

LOCAL y3:=SUB(y,2*n+1,m);

LOCAL s1:=ΣLIST(LN(y1));

LOCAL s2:=ΣLIST(LN(y2));

LOCAL s3:=ΣLIST(LN(y3));

LOCAL c:=((s3-s2)/(s2-s1))^(1/n);

LOCAL b:=e^((s2-s1)*(c-1)/

(1-c^n)^2);

LOCAL a:=e^(1/n*(s1+(s2-s1)/

(1-c^n)));

LOCAL v:=[[a],[b],[c]];

// Making dmat,ymat

LOCAL dmat,ymat,I,k1,k2,k3,k4;

dmat:=[[0,0,0]];

ymat:=[[0]];

FOR I FROM 0 TO m-1 DO

k1:=b^c^I;

k2:=k1*a/b*c^I;

k3:=k2*LN(b)*I;

k4:=y(I+1)-a*(b^c^I);

dmat:=ADDROW(dmat,[k1,k2,k3],

I+1);

ymat:=ADDROW(ymat,[k4],I+1);

END;

dmat:=DELROW(dmat,I+1);

ymat:=DELROW(ymat,I+1);

// new param

LOCAL vt:=(TRN(dmat)*dmat)*

TRN(dmat)*ymat;

LOCAL v1:=v+vt;

RETURN v1;

END;