DATA:	FILE IS data.dat;
VARIABLE:	NAMES ARE y0 y3 y6 y9 x;
MODEL:	i s q | y0@0 y3@3 y6@6 y9@9;
 i ON x (a1); s ON x (a2); q ON x (a3);
MODEL CONSTRAINT:
NEW(i1 i2 i3 i4 s1 s2 s3 s4);
!i1 i2 i3 i4C_Ƃ́CxؕЂɗ^e
a1 = -a2*0 - a3*0**2 + i1;
a1 = -a2*3 - a3*3**2 + i2;
a1 = -a2*6 - a3*6**2 + i3;
a1 = -a2*9 - a3*9**2 + i4;
!s1 s2 s3 s4C_Ƃ́Cxωɗ^e
a2 = -2*a3*0 + s1;
a2 = -2*a3*3 + s2;
a2 = -2*a3*6 + s3;
a2 = -2*a3*9 + s4;