예제 #1
0
파일: lm_mcmcbas.c 프로젝트: cran/BAS
// [[register]]
SEXP mcmcbas(SEXP Y, SEXP X, SEXP Rweights, SEXP Rprobinit, SEXP Rmodeldim, SEXP incint, SEXP Ralpha,SEXP method, SEXP modelprior, SEXP Rupdate, SEXP Rbestmodel,  SEXP plocal,
             SEXP BURNIN_Iterations, SEXP MCMC_Iterations, SEXP LAMBDA, SEXP DELTA,
             SEXP Rparents)
{

  SEXP   RXwork = PROTECT(duplicate(X)), RYwork = PROTECT(duplicate(Y));
  int nProtected = 2, nUnique=0, newmodel=0;
  int nModels=LENGTH(Rmodeldim);

  //  Rprintf("Allocating Space for %d Models\n", nModels) ;
  SEXP ANS = PROTECT(allocVector(VECSXP, 15)); ++nProtected;
  SEXP ANS_names = PROTECT(allocVector(STRSXP, 15)); ++nProtected;
  SEXP Rprobs = PROTECT(duplicate(Rprobinit)); ++nProtected;
  SEXP MCMCprobs= PROTECT(duplicate(Rprobinit)); ++nProtected;
  SEXP R2 = PROTECT(allocVector(REALSXP, nModels)); ++nProtected;
  SEXP shrinkage = PROTECT(allocVector(REALSXP, nModels)); ++nProtected;
  SEXP modelspace = PROTECT(allocVector(VECSXP, nModels)); ++nProtected;
  SEXP modeldim =  PROTECT(duplicate(Rmodeldim)); ++nProtected;
  SEXP counts =  PROTECT(duplicate(Rmodeldim)); ++nProtected;
  SEXP beta = PROTECT(allocVector(VECSXP, nModels)); ++nProtected;
  SEXP se = PROTECT(allocVector(VECSXP, nModels)); ++nProtected;
  SEXP mse = PROTECT(allocVector(REALSXP, nModels)); ++nProtected;
  SEXP modelprobs = PROTECT(allocVector(REALSXP, nModels)); ++nProtected;
  SEXP priorprobs = PROTECT(allocVector(REALSXP, nModels)); ++nProtected;
  SEXP logmarg = PROTECT(allocVector(REALSXP, nModels)); ++nProtected;
  SEXP sampleprobs = PROTECT(allocVector(REALSXP, nModels)); ++nProtected;
  SEXP NumUnique = PROTECT(allocVector(INTSXP, 1)); ++nProtected;
  SEXP Rse_m = NULL, Rcoef_m = NULL, Rmodel_m;

  double *Xwork, *Ywork, *wts, *coefficients,*probs, shrinkage_m, *MCMC_probs,
    SSY, yty, mse_m, *se_m, MH=0.0, prior_m=1.0, *real_model,
    R2_m, RSquareFull, alpha, prone, denom, logmargy, postold, postnew;
  int nobs, p, k, i, j, m, n, l, pmodel, pmodel_old, *xdims, *model_m, *bestmodel, *varin, *varout;
  int mcurrent,  update, n_sure;
  double  mod, rem, problocal, *pigamma,  eps, *hyper_parameters;
  double *XtX, *XtY, *XtXwork, *XtYwork, *SSgam, *Cov, *priorCov, *marg_probs;
  double  lambda,  delta, one=1.0;

  int inc=1;
  int *model, *modelold, bit, *modelwork, old_loc, new_loc;
  //  char uplo[] = "U", trans[]="T";
  struct Var *vars;	/* Info about the model variables. */
  NODEPTR tree, branch;

  /* get dimsensions of all variables */


  nobs = LENGTH(Y);
  xdims = INTEGER(getAttrib(X,R_DimSymbol));
  p = xdims[1];
  k = LENGTH(modelprobs);
  update = INTEGER(Rupdate)[0];
  lambda=REAL(LAMBDA)[0];
  delta = REAL(DELTA)[0];
  //  Rprintf("delta %f lambda %f", delta, lambda);
  eps = DBL_EPSILON;
  problocal = REAL(plocal)[0];
  //  Rprintf("Update %i and prob.switch %f\n", update, problocal);
  /* Extract prior on models  */
  hyper_parameters = REAL(getListElement(modelprior,"hyper.parameters"));

  /*  Rprintf("n %d p %d \n", nobs, p);  */

  Ywork = REAL(RYwork);
  Xwork = REAL(RXwork);
  wts = REAL(Rweights);


 /* Allocate other variables.  */

  PrecomputeData(Xwork, Ywork, wts, &XtXwork, &XtYwork, &XtX, &XtY, &yty, &SSY, p, nobs);

  alpha = REAL(Ralpha)[0];

  vars = (struct Var *) R_alloc(p, sizeof(struct Var));
  probs =  REAL(Rprobs);
  n = sortvars(vars, probs, p);

  for (i =n; i <p; i++) REAL(MCMCprobs)[vars[i].index] = probs[vars[i].index];
  for (i =0; i <n; i++) REAL(MCMCprobs)[vars[i].index] = 0.0;
  MCMC_probs =  REAL(MCMCprobs);


  pigamma = vecalloc(p);
  real_model = vecalloc(n);
  marg_probs = vecalloc(n);
  modelold = ivecalloc(p);
  model = ivecalloc(p);
  modelwork= ivecalloc(p);
  varin= ivecalloc(p);
  varout= ivecalloc(p);


  /* create gamma gamma' matrix */
  SSgam  = (double *) R_alloc(n * n, sizeof(double));
  Cov  = (double *) R_alloc(n * n, sizeof(double));
  priorCov  = (double *) R_alloc(n * n, sizeof(double));
  for (j=0; j < n; j++) {
    for (i = 0; i < n; i++) {
      SSgam[j*n + i] = 0.0;
      Cov[j*n + i] = 0.0;
      priorCov[j*n + i] = 0.0;
      if (j == i)  priorCov[j*n + i] = lambda;
    }
    marg_probs[i] = 0.0;
  }





  RSquareFull = CalculateRSquareFull(XtY, XtX, XtXwork, XtYwork, Rcoef_m, Rse_m, p, nobs, yty, SSY);


  /* fill in the sure things */
  for (i = n, n_sure = 0; i < p; i++)  {
      model[vars[i].index] = (int) vars[i].prob;
      if (model[vars[i].index] == 1) ++n_sure;
  }


  GetRNGstate();
  tree = make_node(-1.0);

  /*  Rprintf("For m=0, Initialize Tree with initial Model\n");  */

  m = 0;
  bestmodel = INTEGER(Rbestmodel);

  INTEGER(modeldim)[m] = n_sure;

  /* Rprintf("Create Tree\n"); */
   branch = tree;

   for (i = 0; i< n; i++) {
      bit =  bestmodel[vars[i].index];
      if (bit == 1) {
	if (i < n-1 && branch->one == NULL)
	  branch->one = make_node(-1.0);
	if (i == n-1 && branch->one == NULL)
	  branch->one = make_node(0.0);
	branch = branch->one;
      }
      else {
	if (i < n-1 && branch->zero == NULL)
	  branch->zero = make_node(-1.0);
	if (i == n-1 && branch->zero == NULL)
	  branch->zero = make_node(0.0);
	branch = branch->zero;
      }

      model[vars[i].index] = bit;
      INTEGER(modeldim)[m]  += bit;
      branch->where = 0;
   }



    /*    Rprintf("Now get model specific calculations \n"); */

    pmodel = INTEGER(modeldim)[m];
    PROTECT(Rmodel_m = allocVector(INTSXP,pmodel));
    model_m = INTEGER(Rmodel_m);

      for (j = 0, l=0; j < p; j++) {
      	if (model[j] == 1) {
            model_m[l] = j;
           l +=1;}
      }

    SET_ELEMENT(modelspace, m, Rmodel_m);

    Rcoef_m = NEW_NUMERIC(pmodel); PROTECT(Rcoef_m);
    Rse_m = NEW_NUMERIC(pmodel);   PROTECT(Rse_m);
    coefficients = REAL(Rcoef_m);
    se_m = REAL(Rse_m);

      for (j=0, l=0; j < pmodel; j++) {
        XtYwork[j] = XtY[model_m[j]];
        for  ( i = 0; i < pmodel; i++) {
	         XtXwork[j*pmodel + i] = XtX[model_m[j]*p + model_m[i]];
	}
      }

    R2_m = 0.0;
    mse_m = yty;
    memcpy(coefficients, XtYwork, sizeof(double)*pmodel);
    cholreg(XtYwork, XtXwork, coefficients, se_m, &mse_m, pmodel, nobs);

    if (pmodel > 1)   R2_m = 1.0 - (mse_m * (double) ( nobs - pmodel))/SSY;

    SET_ELEMENT(beta, m, Rcoef_m);
    SET_ELEMENT(se, m, Rse_m);

    REAL(R2)[m] = R2_m;
    REAL(mse)[m] = mse_m;

    gexpectations(p, pmodel, nobs, R2_m, alpha, INTEGER(method)[0], RSquareFull, SSY, &logmargy, &shrinkage_m);

    REAL(sampleprobs)[m] = 1.0;
    REAL(logmarg)[m] = logmargy;
    REAL(shrinkage)[m] = shrinkage_m;
    prior_m  = compute_prior_probs(model,pmodel,p, modelprior);
    REAL(priorprobs)[m] = prior_m;

    UNPROTECT(3);


    old_loc = 0;
    pmodel_old = pmodel;
    nUnique=1;
    INTEGER(counts)[0] = 0;
    postold =  REAL(logmarg)[m] + log(REAL(priorprobs)[m]);
    memcpy(modelold, model, sizeof(int)*p);
  /*   Rprintf("model %d max logmarg %lf\n", m, REAL(logmarg)[m]); */

    /*  Rprintf("Now Sample the Rest of the Models \n");  */


  m = 0;

  while (nUnique < k && m < INTEGER(BURNIN_Iterations)[0]) {

    memcpy(model, modelold, sizeof(int)*p);
    pmodel =  n_sure;
    MH = 1.0;

    if (pmodel_old == n_sure || pmodel_old == n_sure + n){
	MH =  random_walk(model, vars,  n);
	MH =  1.0 - problocal;
    }
    else {
      if (unif_rand() < problocal) {
      // random
	MH =  random_switch(model, vars, n, pmodel_old, varin, varout );
      }
      else {
      // Randomw walk proposal flip bit//
	MH =  random_walk(model, vars,  n);
      }
    }

    branch = tree;
    newmodel= 0;

    for (i = 0; i< n; i++) {
      bit =  model[vars[i].index];

      if (bit == 1) {
	if (branch->one != NULL) branch = branch->one;
	else newmodel = 1;
	}
      else {
	if (branch->zero != NULL)  branch = branch->zero;
	else newmodel = 1.0;
      }
      pmodel  += bit;
    }

    if (pmodel  == n_sure || pmodel == n + n_sure)  MH = 1.0/(1.0 - problocal);

    if (newmodel == 1) {
      new_loc = nUnique;
      PROTECT(Rmodel_m = allocVector(INTSXP,pmodel));
      model_m = INTEGER(Rmodel_m);
      for (j = 0, l=0; j < p; j++) {
	if (model[j] == 1) {
	  model_m[l] = j;
	  l +=1;}
      }

      Rcoef_m = NEW_NUMERIC(pmodel); PROTECT(Rcoef_m);
      Rse_m = NEW_NUMERIC(pmodel);   PROTECT(Rse_m);
      coefficients = REAL(Rcoef_m);
      se_m = REAL(Rse_m);
      for (j=0, l=0; j < pmodel; j++) {
        XtYwork[j] = XtY[model_m[j]];
        for  ( i = 0; i < pmodel; i++) {
	  XtXwork[j*pmodel + i] = XtX[model_m[j]*p + model_m[i]];
	}
      }
      R2_m = 0.0;
      mse_m = yty;
      memcpy(coefficients, XtYwork, sizeof(double)*pmodel);
      cholreg(XtYwork, XtXwork, coefficients, se_m, &mse_m, pmodel, nobs);
      if (pmodel > 1)  R2_m = 1.0 - (mse_m * (double) ( nobs - pmodel))/SSY;
      prior_m = compute_prior_probs(model,pmodel,p, modelprior);
      gexpectations(p, pmodel, nobs, R2_m, alpha, INTEGER(method)[0], RSquareFull, SSY, &logmargy, &shrinkage_m);
      postnew = logmargy + log(prior_m);
    }
    else {
      new_loc = branch->where;
      postnew =  REAL(logmarg)[new_loc] + log(REAL(priorprobs)[new_loc]);
    }

    MH *= exp(postnew - postold);
    //    Rprintf("MH new %lf old %lf\n", postnew, postold);
    if (unif_rand() < MH) {

      if (newmodel == 1)  {
	new_loc = nUnique;
	insert_model_tree(tree, vars, n, model, nUnique);

	INTEGER(modeldim)[nUnique] = pmodel;
	SET_ELEMENT(modelspace, nUnique, Rmodel_m);

	SET_ELEMENT(beta, nUnique, Rcoef_m);
	SET_ELEMENT(se, nUnique, Rse_m);

	REAL(R2)[nUnique] = R2_m;
	REAL(mse)[nUnique] = mse_m;
	REAL(sampleprobs)[nUnique] = 1.0;
	REAL(logmarg)[nUnique] = logmargy;
	REAL(shrinkage)[nUnique] = shrinkage_m;
	REAL(priorprobs)[nUnique] = prior_m;
	UNPROTECT(3);
	++nUnique;
      }

      old_loc = new_loc;
      postold = postnew;
      pmodel_old = pmodel;
      memcpy(modelold, model, sizeof(int)*p);
    }
    else  {
      if (newmodel == 1) UNPROTECT(3);
    }

    INTEGER(counts)[old_loc] += 1;

    for (i = 0; i < n; i++) {
      /* store in opposite order so nth variable is first */
     real_model[n-1-i] = (double) modelold[vars[i].index];
     REAL(MCMCprobs)[vars[i].index] += (double) modelold[vars[i].index];
   }

   // Update SSgam = gamma gamma^T + SSgam
   F77_NAME(dsyr)("U", &n,  &one, &real_model[0], &inc,  &SSgam[0], &n);
   m++;
  }

 for (i = 0; i < n; i++) {
     REAL(MCMCprobs)[vars[i].index] /= (double) m;
 }
  //  Rprintf("\n%d \n", nUnique);


// Compute marginal probabilities
  mcurrent = nUnique;
  compute_modelprobs(modelprobs, logmarg, priorprobs,mcurrent);
  compute_margprobs(modelspace, modeldim, modelprobs, probs, mcurrent, p);



//  Now sample W/O Replacement
// Rprintf("NumUnique Models Accepted %d \n", nUnique);
 INTEGER(NumUnique)[0] = nUnique;


 if (nUnique < k) {
   update_probs(probs, vars, mcurrent, k, p);
   update_tree(modelspace, tree, modeldim, vars, k,p,n,mcurrent, modelwork);
  for (m = nUnique;  m < k; m++) {
    for (i = n; i < p; i++)  {
      INTEGER(modeldim)[m]  +=  model[vars[i].index];
    }

    branch = tree;

    for (i = 0; i< n; i++) {
      pigamma[i] = 1.0;
      bit =  withprob(branch->prob);

      /*    branch->done += 1; */

	if (bit == 1) {
	  for (j=0; j<=i; j++)  pigamma[j] *= branch->prob;
	  if (i < n-1 && branch->one == NULL)
	    branch->one = make_node(vars[i+1].prob);
          if (i == n-1 && branch->one == NULL)
	    branch->one = make_node(0.0);
	  branch = branch->one;
	}
        else {
	  for (j=0; j<=i; j++)  pigamma[j] *= (1.0 - branch->prob);
	  if (i < n-1 && branch->zero == NULL)
	    branch->zero = make_node(vars[i+1].prob);
          if (i == n-1 && branch->zero == NULL)
	    branch->zero = make_node(0.0);
	  branch = branch->zero;
	  }
	model[vars[i].index] = bit;
	INTEGER(modeldim)[m]  += bit;
    }

    REAL(sampleprobs)[m] = pigamma[0];
    pmodel = INTEGER(modeldim)[m];

    /* Now subtract off the visited probability mass. */
    branch=tree;
    for (i = 0; i < n; i++) {
      bit = model[vars[i].index];
      prone = branch->prob;
      if (bit == 1) prone -= pigamma[i];
      denom = 1.0 - pigamma[i];
      if (denom <= 0.0) {
	if (denom < 0.0) {
	  warning("neg denominator %le %le %le !!!\n", pigamma, denom, prone);
	  if (branch->prob < 0.0 && branch->prob < 1.0)
	    warning("non extreme %le\n", branch->prob);}
        denom = 0.0;}
      else {
	if  (prone <= 0)  prone = 0.0;
	if  (prone > denom)  {
          if (prone <= eps) prone = 0.0;
	  else prone = 1.0;
	  /* Rprintf("prone > 1 %le %le %le %le !!!\n", pigamma, denom, prone, eps);*/
	}
	else prone = prone/denom;
      }
      if (prone > 1.0 || prone < 0.0)
		Rprintf("%d %d Probability > 1!!! %le %le  %le %le \n",
		m, i, prone, branch->prob, denom, pigamma);


      /*      if (bit == 1)  pigamma /= (branch->prob);
	      else  pigamma /= (1.0 - branch->prob);
	      if (pigamma > 1.0) pigamma = 1.0; */
      branch->prob  = prone;
      if (bit == 1) branch = branch->one;
      else  branch = branch->zero;

      /*      Rprintf("%d %d \n",  branch->done, n - i); */
      /*      if (log((double) branch->done) < (n - i)*log(2.0)) {
	if (bit == 1) branch = branch->one;
	else  branch = branch->zero;
      }
      else {
	    branch->one = NULL;
	    branch->zero = NULL;
	    break; } */
    }

    /* Now get model specific calculations */

      PROTECT(Rmodel_m = allocVector(INTSXP, pmodel));
      model_m = INTEGER(Rmodel_m);

      for (j = 0, l=0; j < p; j++) {
	if (model[j] == 1) {
           model_m[l] = j;
           l +=1;}
      }


     SET_ELEMENT(modelspace, m, Rmodel_m);

      for (j=0, l=0; j < pmodel; j++) {
         XtYwork[j] = XtY[model_m[j]];
        for  ( i = 0; i < pmodel; i++) {
	 XtXwork[j*pmodel + i] = XtX[model_m[j]*p + model_m[i]];
	}

      }


      PROTECT(Rcoef_m = allocVector(REALSXP,pmodel));
      PROTECT(Rse_m = allocVector(REALSXP,pmodel));
      coefficients = REAL(Rcoef_m);
      se_m = REAL(Rse_m);

    mse_m = yty;
    memcpy(coefficients, XtYwork, sizeof(double)*pmodel);
    cholreg(XtYwork, XtXwork, coefficients, se_m, &mse_m, pmodel, nobs);


/*    olsreg(Ywork, Xwork, coefficients, se_m, &mse_m, &pmodel, &nobs, pivot,qraux,work,residuals,effects,v,betaols);   */
    if (pmodel > 1)  R2_m = 1.0 - (mse_m * (double) ( nobs - pmodel))/SSY;

    SET_ELEMENT(beta, m, Rcoef_m);
    SET_ELEMENT(se, m, Rse_m);

    REAL(R2)[m] = R2_m;
    REAL(mse)[m] = mse_m;

   gexpectations(p, pmodel, nobs, R2_m, alpha, INTEGER(method)[0],  RSquareFull, SSY, &logmargy, &shrinkage_m);
   REAL(logmarg)[m] = logmargy;
   REAL(shrinkage)[m] = shrinkage_m;
   REAL(priorprobs)[m] = compute_prior_probs(model,pmodel,p, modelprior);


    if (m > 1) {
      rem = modf((double) m/(double) update, &mod);
      if (rem  == 0.0) {
	mcurrent = m;
	compute_modelprobs(modelprobs, logmarg, priorprobs,mcurrent);
	compute_margprobs(modelspace, modeldim, modelprobs, probs, mcurrent, p);
	if (update_probs(probs, vars, mcurrent, k, p) == 1) {
//	  Rprintf("Updating Model Tree %d \n", m);
	  update_tree(modelspace, tree, modeldim, vars, k,p,n,mcurrent, modelwork);
	}

      }}
    UNPROTECT(3);
  }
 }

 compute_modelprobs(modelprobs, logmarg, priorprobs,k);
 compute_margprobs(modelspace, modeldim, modelprobs, probs, k, p);

  SET_VECTOR_ELT(ANS, 0, Rprobs);
  SET_STRING_ELT(ANS_names, 0, mkChar("probne0"));

  SET_VECTOR_ELT(ANS, 1, modelspace);
  SET_STRING_ELT(ANS_names, 1, mkChar("which"));

  SET_VECTOR_ELT(ANS, 2, logmarg);
  SET_STRING_ELT(ANS_names, 2, mkChar("logmarg"));

  SET_VECTOR_ELT(ANS, 3, modelprobs);
  SET_STRING_ELT(ANS_names, 3, mkChar("postprobs"));

  SET_VECTOR_ELT(ANS, 4, priorprobs);
  SET_STRING_ELT(ANS_names, 4, mkChar("priorprobs"));

  SET_VECTOR_ELT(ANS, 5,sampleprobs);
  SET_STRING_ELT(ANS_names, 5, mkChar("sampleprobs"));

  SET_VECTOR_ELT(ANS, 6, mse);
  SET_STRING_ELT(ANS_names, 6, mkChar("mse"));

  SET_VECTOR_ELT(ANS, 7, beta);
  SET_STRING_ELT(ANS_names, 7, mkChar("mle"));

  SET_VECTOR_ELT(ANS, 8, se);
  SET_STRING_ELT(ANS_names, 8, mkChar("mle.se"));

  SET_VECTOR_ELT(ANS, 9, shrinkage);
  SET_STRING_ELT(ANS_names, 9, mkChar("shrinkage"));

  SET_VECTOR_ELT(ANS, 10, modeldim);
  SET_STRING_ELT(ANS_names, 10, mkChar("size"));

  SET_VECTOR_ELT(ANS, 11, R2);
  SET_STRING_ELT(ANS_names, 11, mkChar("R2"));

  SET_VECTOR_ELT(ANS, 12, counts);
  SET_STRING_ELT(ANS_names, 12, mkChar("freq"));

  SET_VECTOR_ELT(ANS, 13, MCMCprobs);
  SET_STRING_ELT(ANS_names, 13, mkChar("probs.MCMC"));

  SET_VECTOR_ELT(ANS, 14, NumUnique);
  SET_STRING_ELT(ANS_names, 14, mkChar("n.Unique"));

  setAttrib(ANS, R_NamesSymbol, ANS_names);
  UNPROTECT(nProtected);
//  Rprintf("Return\n");
  PutRNGstate();

  return(ANS);
}
예제 #2
0
SEXP sampleworep_new(SEXP Y, SEXP X, SEXP Rweights, SEXP Rprobinit, SEXP Rmodeldim, SEXP incint, SEXP Ralpha,SEXP method, SEXP modelprior, SEXP Rupdate, SEXP Rbestmodel, SEXP Rbestmarg, SEXP plocal) {
	int nProtected = 0;
	SEXP RXwork = PROTECT(duplicate(X)); nProtected++;
	SEXP RYwork = PROTECT(duplicate(Y)); nProtected++;
	int nModels=LENGTH(Rmodeldim);

	//  Rprintf("Allocating Space for %d Models\n", nModels) ;
	SEXP ANS = PROTECT(allocVector(VECSXP, 12)); ++nProtected;
	SEXP ANS_names = PROTECT(allocVector(STRSXP, 12)); ++nProtected;
	SEXP Rprobs = PROTECT(duplicate(Rprobinit)); ++nProtected;
	SEXP R2 = PROTECT(allocVector(REALSXP, nModels)); ++nProtected;
	SEXP shrinkage = PROTECT(allocVector(REALSXP, nModels)); ++nProtected;
	SEXP modelspace = PROTECT(allocVector(VECSXP, nModels)); ++nProtected;
	SEXP modeldim =  PROTECT(duplicate(Rmodeldim)); ++nProtected;
	SEXP beta = PROTECT(allocVector(VECSXP, nModels)); ++nProtected;
	SEXP se = PROTECT(allocVector(VECSXP, nModels)); ++nProtected;
	SEXP mse = PROTECT(allocVector(REALSXP, nModels)); ++nProtected;
	SEXP modelprobs = PROTECT(allocVector(REALSXP, nModels)); ++nProtected;
	SEXP priorprobs = PROTECT(allocVector(REALSXP, nModels)); ++nProtected;
	SEXP logmarg = PROTECT(allocVector(REALSXP, nModels)); ++nProtected;
	SEXP sampleprobs = PROTECT(allocVector(REALSXP, nModels)); ++nProtected;

	double *Xwork, *Ywork, *wts, *probs, shrinkage_m, mse_m, R2_m, RSquareFull, logmargy;
	int i;
	
	//get dimsensions of all variables 
	int nobs = LENGTH(Y);
	int p = INTEGER(getAttrib(X,R_DimSymbol))[1];
	int k = LENGTH(modelprobs);
	double alpha = REAL(Ralpha)[0];
	
	int update = INTEGER(Rupdate)[0];
	double eps = DBL_EPSILON;
	double problocal = REAL(plocal)[0];

	Ywork = REAL(RYwork);
	Xwork = REAL(RXwork);
	wts = REAL(Rweights);
	
	double *XtXwork, *XtYwork,*XtX, *XtY, yty,SSY;
	PrecomputeData(Xwork, Ywork, wts, &XtXwork, &XtYwork, &XtX, &XtY, &yty, &SSY, p, nobs);

	struct Var *vars = (struct Var *) R_alloc(p, sizeof(struct Var)); // Info about the model variables. 
	probs =  REAL(Rprobs);
	int n = sortvars(vars, probs, p); 
 
	SEXP  Rse_m = NULL, Rcoef_m = NULL; 
	RSquareFull = CalculateRSquareFull(XtY, XtX, XtXwork, XtYwork, Rcoef_m, Rse_m, p, nobs, yty, SSY);
	
	int *model = ivecalloc(p);
	/* fill in the sure things */
	for (i = n; i < p; i++)  {
		model[vars[i].index] = (int) vars[i].prob;
	}

	GetRNGstate();

	NODEPTR tree, branch;	
	tree = make_node(vars[0].prob);
	//	Rprintf("For m=0, Initialize Tree with initial Model\n");  
	
	int m = 0;
	int *bestmodel = INTEGER(Rbestmodel);
	for (i = n; i < p; i++)  {
		model[vars[i].index] = bestmodel[vars[i].index];
		INTEGER(modeldim)[m]  +=  bestmodel[vars[i].index];
	}

	double *pigamma = vecalloc(p);
	branch = tree;
	CreateTree_with_pigamma(branch, vars, bestmodel, model, n, m, modeldim,pigamma);

	branch=tree;
	Substract_visited_probability_mass(branch, vars, model, n, m, pigamma,eps);

	int pmodel = INTEGER(modeldim)[m];
	SEXP Rmodel_m;
	PROTECT(Rmodel_m = allocVector(INTSXP,pmodel));
	PROTECT(Rcoef_m = NEW_NUMERIC(pmodel)); 
	PROTECT(Rse_m = NEW_NUMERIC(pmodel));  
	int *model_m = GetModel_m(Rmodel_m, model, p);

	R2_m = FitModel(Rcoef_m, Rse_m, XtY, XtX, model_m, XtYwork, XtXwork, yty, SSY, pmodel, p, nobs, m, &mse_m);
	gexpectations(p, pmodel, nobs, R2_m, alpha, INTEGER(method)[0], RSquareFull, SSY, &logmargy, &shrinkage_m);
	double prior_m  = compute_prior_probs(model,pmodel,p, modelprior);
	REAL(Rbestmarg)[0] = REAL(logmarg)[m];
	
	SetModel2(logmargy, shrinkage_m, prior_m, sampleprobs, logmarg, shrinkage, priorprobs, m);
	SetModel(Rcoef_m, Rse_m, Rmodel_m, mse_m, R2_m,	beta, se, modelspace, mse, R2, m);
	//Rprintf("model %d max logmarg %lf\n", m, REAL(logmarg)[m]);

	int *modelwork= ivecalloc(p);
	for (m = 1;  m < k; m++) {
		for (i = n; i < p; i++)  {
			INTEGER(modeldim)[m]  +=  model[vars[i].index];
		}

		branch = tree;
		GetNextModel_swop(branch, vars, model, n, m, pigamma, problocal, modeldim, bestmodel);
		
		/* Now subtract off the visited probability mass. */
		branch=tree;
		Substract_visited_probability_mass(branch, vars, model, n, m, pigamma,eps);
		
		/* Now get model specific calculations */
		pmodel = INTEGER(modeldim)[m];
		PROTECT(Rmodel_m = allocVector(INTSXP,pmodel));
		PROTECT(Rcoef_m = NEW_NUMERIC(pmodel)); 
		PROTECT(Rse_m = NEW_NUMERIC(pmodel));   
		model_m = GetModel_m(Rmodel_m, model, p);
		R2_m = FitModel(Rcoef_m, Rse_m, XtY, XtX, model_m, XtYwork, XtXwork, yty, SSY, pmodel, p, nobs, m, &mse_m);
		gexpectations(p, pmodel, nobs, R2_m, alpha, INTEGER(method)[0], RSquareFull, SSY, &logmargy, &shrinkage_m);
		prior_m = compute_prior_probs(model,pmodel,p, modelprior);
		SetModel2(logmargy, shrinkage_m, prior_m, sampleprobs, logmarg, shrinkage, priorprobs, m);
		SetModel(Rcoef_m, Rse_m, Rmodel_m, mse_m, R2_m,	beta, se, modelspace, mse, R2,m);
		REAL(sampleprobs)[m] = pigamma[0];  

		//update best model
		if (REAL(logmarg)[m] > REAL(Rbestmarg)[0]) {
			for (i=0; i < p; i++) {
				bestmodel[i] = model[i];
			}
			REAL(Rbestmarg)[0] = REAL(logmarg)[m];
		}
		
		//update marginal inclusion probs
		if (m > 1) {
			double mod; 
			double rem = modf((double) m/(double) update, &mod);
			if (rem  == 0.0) {
				int mcurrent = m;
				compute_modelprobs(modelprobs, logmarg, priorprobs,mcurrent);
				compute_margprobs(modelspace, modeldim, modelprobs, probs, mcurrent, p);        
				if (update_probs(probs, vars, mcurrent, k, p) == 1) {
				  //					Rprintf("Updating Model Tree %d \n", m);
					update_tree(modelspace, tree, modeldim, vars, k,p,n,mcurrent, modelwork);     
				}
			}
		}  
	}

	compute_modelprobs(modelprobs, logmarg, priorprobs,k);
	compute_margprobs(modelspace, modeldim, modelprobs, probs, k, p);  

	SET_VECTOR_ELT(ANS, 0, Rprobs);
	SET_STRING_ELT(ANS_names, 0, mkChar("probne0"));

	SET_VECTOR_ELT(ANS, 1, modelspace);
	SET_STRING_ELT(ANS_names, 1, mkChar("which"));

	SET_VECTOR_ELT(ANS, 2, logmarg);
	SET_STRING_ELT(ANS_names, 2, mkChar("logmarg"));

	SET_VECTOR_ELT(ANS, 3, modelprobs);
	SET_STRING_ELT(ANS_names, 3, mkChar("postprobs"));

	SET_VECTOR_ELT(ANS, 4, priorprobs);
	SET_STRING_ELT(ANS_names, 4, mkChar("priorprobs"));

	SET_VECTOR_ELT(ANS, 5,sampleprobs);
	SET_STRING_ELT(ANS_names, 5, mkChar("sampleprobs"));

	SET_VECTOR_ELT(ANS, 6, mse);
	SET_STRING_ELT(ANS_names, 6, mkChar("mse"));

	SET_VECTOR_ELT(ANS, 7, beta);
	SET_STRING_ELT(ANS_names, 7, mkChar("mle"));

	SET_VECTOR_ELT(ANS, 8, se);
	SET_STRING_ELT(ANS_names, 8, mkChar("mle.se"));

	SET_VECTOR_ELT(ANS, 9, shrinkage);
	SET_STRING_ELT(ANS_names, 9, mkChar("shrinkage"));

	SET_VECTOR_ELT(ANS, 10, modeldim);
	SET_STRING_ELT(ANS_names, 10, mkChar("size"));

	SET_VECTOR_ELT(ANS, 11, R2);
	SET_STRING_ELT(ANS_names, 11, mkChar("R2"));

	setAttrib(ANS, R_NamesSymbol, ANS_names);
	UNPROTECT(nProtected);

	PutRNGstate();
	return(ANS);  
}