use fish,replace
qui ipf [fw=freq], fit(food+lake*size*gender)  
qui ipf [fw=freq], fit(food*gender+lake*size*gender)  
qui ipf [fw=freq], fit(food*size+lake*size*gender)  
qui ipf [fw=freq], fit(food*lake+lake*size*gender)  
qui ipf [fw=freq], fit(food*lake+food*size+lake*size*gender)  
qui ipf [fw=freq], fit(food*lake+food*size+food*gender+lake*size*gender) 
qui ipf [fw=freq], fit(food  +lake*size)  
qui ipf [fw=freq], fit(food*size  +lake*size) 
qui ipf [fw=freq], fit(food*lake  +lake*size) 
qui ipf [fw=freq], fit(food*lake + food*size+lake*size) 

  

use mantel,replace
ipf [fw=freq], fit( D + E) exp
ipf [fw=freq], fit( D + E) constr([D==0 & E==0]2) exp
ipf [fw=freq], fit( D + E) convars(D E) confile(constr) exp

use mantel3,replace
ipf [fw=freq], fit( D + E) convars(D E) confile(constr1) exp