func (f *oneVsAllFilter) Transform(old, to base.Attribute, seq []byte) []byte {
if !old.Equals(f.classAttr) {
return seq
}
val := base.UnpackBytesToU64(seq)
if val == f.classAttrVal {
return base.PackFloatToBytes(1.0)
}
return base.PackFloatToBytes(0.0)
}
// AddAttribute add a given numeric Attribute `attr' to the
// filter.
//
// IMPORTANT: This function panic()s if it can't locate the
// attribute in the Instances set.
func (c *ChiMergeFilter) AddAttribute(attr base.Attribute) {
if attr.GetType() != base.Float64Type {
panic("ChiMerge only works on Float64Attributes")
}
attrIndex := c.Instances.GetAttrIndex(attr)
if attrIndex == -1 {
panic("Invalid attribute!")
}
c.Attributes = append(c.Attributes, attrIndex)
}
func TestBinning(t *testing.T) {
Convey("Given some data and a reference", t, func() {
// Read the data
inst1, err := base.ParseCSVToInstances("../examples/datasets/iris_headers.csv", true)
if err != nil {
panic(err)
}
inst2, err := base.ParseCSVToInstances("../examples/datasets/iris_binned.csv", true)
if err != nil {
panic(err)
}
//
// Construct the binning filter
binAttr := inst1.AllAttributes()[0]
filt := NewBinningFilter(inst1, 10)
filt.AddAttribute(binAttr)
filt.Train()
inst1f := base.NewLazilyFilteredInstances(inst1, filt)
// Retrieve the categorical version of the original Attribute
var cAttr base.Attribute
for _, a := range inst1f.AllAttributes() {
if a.GetName() == binAttr.GetName() {
cAttr = a
}
}
cAttrSpec, err := inst1f.GetAttribute(cAttr)
So(err, ShouldEqual, nil)
binAttrSpec, err := inst2.GetAttribute(binAttr)
So(err, ShouldEqual, nil)
//
// Create the LazilyFilteredInstances
// and check the values
Convey("Discretized version should match reference", func() {
_, rows := inst1.Size()
for i := 0; i < rows; i++ {
val1 := inst1f.Get(cAttrSpec, i)
val2 := inst2.Get(binAttrSpec, i)
val1s := cAttr.GetStringFromSysVal(val1)
val2s := binAttr.GetStringFromSysVal(val2)
So(val1s, ShouldEqual, val2s)
}
})
})
}