Semagle.Data.Formats Library

Semagle.Data.Formats provides reading and writing functions for popular machine learning dataset formats.

LIBSVM

LIBSVM uses "sparse" vector format where zero values do not need to be stored. Each vector is repsented by a separate text line. A first number of the line is the label y (class number or value of the approximated function), which is followed by index/value pairs of non-zero elements of the feature vector x.

1: 
2:

1 1:5.1 3:2 4:-15
2 2:13 8:33

Read Data

Read the sequence of (y, x) pairs from LIBSVM file:

1: 
2: 
3: 
4:

open Semagle.Numerics.Vectors
open Semagle.Data.Formats

LibSVM.read "train file"

Write Data

Write the sequence of (y, x) pairs to LIBSVM file:

1: 
2: 
3: 
4: 
5: 
6: 
7: 
8: 
9:

open Semagle.Numerics.Vectors
open Semagle.Data.Formats

let data = List.toSeq [
    (+1.0f, SparseVector([|0; 3; 7|], [|1.0f; 2.0f; 5.0f|]));
    (+1.0f, SparseVector([|0; 2; 9|], [|3.0f; 2.0f; 5.0f|]));
    (-1.0f, SparseVector([|4; 8|], [|0.1f; 0.5f|]))]

LibSVM.write "train file" data

val data : seq<float32 * obj>

Multiple items
module List

from Microsoft.FSharp.Collections

--------------------
type List<'T> =
  | ( [] )
  | ( :: ) of Head: 'T * Tail: 'T list
    interface IReadOnlyList<'T>
    interface IReadOnlyCollection<'T>
    interface IEnumerable
    interface IEnumerable<'T>
    member GetSlice : startIndex:int option * endIndex:int option -> 'T list
    member Head : 'T
    member IsEmpty : bool
    member Item : index:int -> 'T with get
    member Length : int
    member Tail : 'T list
    ...

val toSeq : list:'T list -> seq<'T>

Semagle.Framework

Semagle.Data.Formats Library

LIBSVM

Read Data

Write Data