Make erasure matrix type not optional choose automatically

Remove option of providing Technique and handling errors based on that
choose a matrix type automatically based on number of data blocks.

INTEL recommends on using cauchy for consistent invertible matrices,
while vandermonde is faster we should default to cauchy for large
data blocks.

pkg/erasure/erasure_encode.go

@@ -17,7 +17,7 @@
 package erasure
 
 // #include <stdlib.h>
-// #include "ec_isal-l.h"
+// #include "ec.h"
 // #include "ec_minio_common.h"
 import "C"
 import (
@@ -25,22 +25,6 @@ import (
 	"unsafe"
 )
 
-// Technique - type of matrix type used in encoding
-type Technique uint8
-
-// Different types of supported matrix types
-const (
-	Vandermonde Technique = iota
-	Cauchy
-	None
-)
-
-// Default Data and Parity blocks
-const (
-	K = 10
-	M = 3
-)
-
 // Block alignment
 const (
 	SIMDAlign = 32
@@ -48,9 +32,8 @@ const (
 
 // Params is a configuration set for building an encoder. It is created using ValidateParams().
 type Params struct {
-	K         uint8
-	M         uint8
-	Technique Technique // cauchy or vandermonde matrix (RS)
+	K uint8
+	M uint8
 }
 
 // Erasure is an object used to encode and decode data.
@@ -66,7 +49,7 @@ type Erasure struct {
 // k and m represent the matrix size, which corresponds to the protection level
 // technique is the matrix type. Valid inputs are Cauchy (recommended) or Vandermonde.
 //
-func ValidateParams(k, m uint8, technique Technique) (*Params, error) {
+func ValidateParams(k, m uint8) (*Params, error) {
 	if k < 1 {
 		return nil, errors.New("k cannot be zero")
 	}
@@ -79,19 +62,9 @@ func ValidateParams(k, m uint8, technique Technique) (*Params, error) {
 		return nil, errors.New("(k + m) cannot be bigger than Galois field GF(2^8) - 1")
 	}
 
-	switch technique {
-	case Vandermonde:
-		break
-	case Cauchy:
-		break
-	default:
-		return nil, errors.New("Technique can be either vandermonde or cauchy")
-	}
-
 	return &Params{
-		K:         k,
-		M:         m,
-		Technique: technique,
+		K: k,
+		M: m,
 	}, nil
 }
 
@@ -103,8 +76,7 @@ func NewErasure(ep *Params) *Erasure {
 	var encodeMatrix *C.uchar
 	var encodeTbls *C.uchar
 
-	C.minio_init_encoder(C.int(ep.Technique), k, m, &encodeMatrix,
-		&encodeTbls)
+	C.minio_init_encoder(k, m, &encodeMatrix, &encodeTbls)
 
 	return &Erasure{
 		params:       ep,