fix: add back bf16 support

this was accidentally removed when moving fs/ggml from its previous
location

fs/ggml/ggml.go

@@ -207,11 +207,26 @@ func (t Tensor) block() (n int) {
 
 func (t Tensor) blockSize() uint64 {
 	switch t.Kind {
-	case 0, 1, 24, 25, 26, 27, 28, 30: // F32, F16, I8, I16, I32, I64, F64, BF16
+	case
+		0,  // F32
+		1,  // F16
+		24, // I8
+		25, // I16
+		26, // I32
+		27, // I64
+		28, // F64
+		30: // BF16
 		return 1
-	case 2, 3, 4, 5, 6, 7, 8, 9, 20: // Q4_0, Q4_1, Q5_0, Q5_1, Q8_0, Q8_1, IQ4_NL
+	case
+		2,  // Q4_0
+		3,  // Q4_1
+		6,  // Q5_0
+		7,  // Q5_1
+		8,  // Q8_0
+		9,  // Q8_1
+		20: // IQ4_NL
 		return 32
-	default: // All others
+	default:
 		return 256
 	}
 }
@@ -235,7 +250,7 @@ func (t Tensor) typeSize() uint64 {
 	case 8: // Q8_0
 		return 2 + blockSize
 	case 9: // Q8_1
-		return 4 + 4 + blockSize
+		return 2 + 2 + blockSize
 	case 10: // Q2_K
 		return blockSize/16 + blockSize/4 + 2 + 2
 	case 11: // Q3_K
@@ -247,7 +262,7 @@ func (t Tensor) typeSize() uint64 {
 	case 14: // Q6_K
 		return blockSize/2 + blockSize/4 + blockSize/16 + 2
 	case 15: // Q8_K
-		return 2 + blockSize + 2*blockSize/16
+		return 4 + blockSize + 2*blockSize/16
 	case 16: // IQ2_XXS
 		return 2 + 2*blockSize/8
 	case 17: // IQ2_XS
@@ -276,6 +291,8 @@ func (t Tensor) typeSize() uint64 {
 		return 8
 	case 29: // IQ1_M
 		return blockSize/8 + blockSize/16 + blockSize/32
+	case 30: // BF16
+		return 2
 	default:
 		return 0
 	}

fs/ggml/ggml_test.go

@@ -3,6 +3,7 @@ package ggml
 import (
 	"maps"
 	"slices"
+	"strconv"
 	"strings"
 	"testing"
 
@@ -157,3 +158,55 @@ func TestTensorLayers(t *testing.T) {
 		})
 	}
 }
+
+// ref: https://github.com/ggml-org/llama.cpp/blob/a82c9e7c23ef6db48cebfa194dc9cebbc4ac3552/ggml/src/ggml.c#L572
+func TestTensorTypes(t *testing.T) {
+	cases := []struct {
+		kind      uint32
+		blockSize uint64
+		typeSize  uint64
+	}{
+		{0, 1, 4},
+		{1, 1, 2},
+		{2, 32, 18},
+		{3, 32, 20},
+		{6, 32, 22},
+		{7, 32, 24},
+		{8, 32, 34},
+		{9, 32, 36},
+		{10, 256, 84},
+		{11, 256, 110},
+		{12, 256, 144},
+		{13, 256, 176},
+		{14, 256, 210},
+		{15, 256, 292},
+		{16, 256, 66},
+		{17, 256, 74},
+		{18, 256, 98},
+		{19, 256, 50},
+		{20, 32, 18},
+		{21, 256, 110},
+		{22, 256, 82},
+		{23, 256, 136},
+		{24, 1, 1},
+		{25, 1, 2},
+		{26, 1, 4},
+		{27, 1, 8},
+		{28, 1, 8},
+		{29, 256, 56},
+		{30, 1, 2},
+	}
+
+	for _, tt := range cases {
+		t.Run(strconv.Itoa(int(tt.kind)), func(t *testing.T) {
+			tensor := Tensor{Kind: tt.kind}
+			if tensor.blockSize() != tt.blockSize {
+				t.Errorf("unexpected block size: got=%d want=%d", tensor.blockSize(), tt.blockSize)
+			}
+
+			if tensor.typeSize() != tt.typeSize {
+				t.Errorf("unexpected type size: got=%d want=%d", tensor.typeSize(), tt.typeSize)
+			}
+		})
+	}
+}