function [par,r1,r2]=estpar(c,g,dt,z)
%for fixed value of g, estimates other three parameters a,b,c
n=length(z)-1;
z1=z(1:n);

[a,b,dz,w]=estdrift(c,g,dt,z);
m = ( a + b*z1).*(exp(b*dt) - 1)/b;
w=w.^2;
y = ((dz-m).^2);
[c,opt]=fmin('estc',.0005, .1, [], z1,y,g,dt,w);



w=weight(c,g,dt,z);
[r1,r2]=resid7(g,a,b,c,dt,z,w);
par=[a b c g log(opt(8)) log(ss(r1)) log(ss(r2))];