source: branches/2929_PrioritizedGrammarEnumeration/HeuristicLab.Algorithms.DataAnalysis.PGE/3.3/src/go-pge/pge/pge_init_method_2.go @ 16620

package pge

import (
  "fmt"

  probs "go-pge/problems"
  expr "go-symexpr"
)

// This is the FFXish style init function
func (PS *PgeSearch) GenInitExprMethod2() *probs.ReportQueue {
  fmt.Printf("generating initial expressions\n")

  GP := PS.cnfg.treecfg
  fmt.Printf("%v\n", GP)

  bases := make([]expr.Expr, 0)

  // single constant
  bases = append(bases, expr.NewConstant(-1))

  // c*x_i
  for _, v := range PS.prob.UsableVars {
    mul := expr.NewMul()
    mul.Insert(expr.NewConstant(-1))
    mul.Insert(expr.NewVar(v))
    bases = append(bases, mul)
  }

  // c*x_i^p & c*x_i^-p
  for p := 2; p <= 4; p++ {
    for _, v := range PS.prob.UsableVars {
      // positive powers
      mul := expr.NewMul()
      mul.Insert(expr.NewConstant(-1))
      mul.Insert(expr.NewPowI(expr.NewVar(v), p))
      bases = append(bases, mul)

      // negative powers
      nul := expr.NewMul()
      nul.Insert(expr.NewConstant(-1))
      nul.Insert(expr.NewPowI(expr.NewVar(v), -p))
      bases = append(bases, nul)
    }
  }

  // c*N(d*x_i)
  for _, N := range PS.GenNodes {
    if N.ExprType() == expr.DIV || N.ExprType() == expr.ADD || N.ExprType() == expr.MUL {
      continue
    }
    for _, v := range PS.prob.UsableVars {
      // positive powers
      mul := expr.NewMul()
      mul.Insert(expr.NewConstant(-1))

      nul := expr.NewMul()
      nul.Insert(expr.NewConstant(-1))
      nul.Insert(expr.NewVar(v))

      n := N.Clone()
      p := 1
      n.SetExpr(&p, nul)
      mul.Insert(n)
      bases = append(bases, mul)
    }
  }

  // copy bases for use later in expand
  PS.ffxBases = make([]expr.Expr, len(bases))
  for i, b := range bases {
    PS.ffxBases[i] = b.Clone()
  }

  exprs := probs.NewReportQueue()
  // exprs.SetSort(PS.cnfg.sortType)
  exprs.SetSort(probs.PESORT_PARETO_TST_ERR)

  for i, e := range bases {
    fmt.Printf("%d:  %v\n", i, e)
    serial := make([]int, 0, 64)
    serial = e.Serial(serial)
    PS.Trie.InsertSerial(serial)
    // on train data
    re := RegressExpr(e, PS.prob)
    re.SetUnitID(i)
    exprs.Push(re)
  }
  exprs.Sort()

  return exprs
}