allow F16 to use metal

warning F16 uses significantly more memory than quantized model so the
standard requires don't apply.

llm/llm.go

@@ -36,11 +36,11 @@ func New(model string, adapters []string, opts api.Options) (LLM, error) {
 	}
 
 	switch ggml.FileType().String() {
-	case "F32", "F16", "Q5_0", "Q5_1", "Q8_0":
+	case "F32", "Q5_0", "Q5_1", "Q8_0":
 		if opts.NumGPU != 0 {
 			// F32, F16, Q5_0, Q5_1, and Q8_0 do not support Metal API and will
 			// cause the runner to segmentation fault so disable GPU
-			log.Printf("WARNING: GPU disabled for F32, F16, Q5_0, Q5_1, and Q8_0")
+			log.Printf("WARNING: GPU disabled for F32, Q5_0, Q5_1, and Q8_0")
 			opts.NumGPU = 0
 		}
 	}
@@ -48,19 +48,27 @@ func New(model string, adapters []string, opts api.Options) (LLM, error) {
 	totalResidentMemory := memory.TotalMemory()
 	switch ggml.ModelType() {
 	case ModelType3B, ModelType7B:
-		if totalResidentMemory < 8*1024*1024 {
+		if ggml.FileType().String() == "F16" && totalResidentMemory < 16*1024*1024 {
+			return nil, fmt.Errorf("F16 model requires at least 16GB of memory")
+		} else if totalResidentMemory < 8*1024*1024 {
 			return nil, fmt.Errorf("model requires at least 8GB of memory")
 		}
 	case ModelType13B:
-		if totalResidentMemory < 16*1024*1024 {
+		if ggml.FileType().String() == "F16" && totalResidentMemory < 32*1024*1024 {
+			return nil, fmt.Errorf("F16 model requires at least 32GB of memory")
+		} else if totalResidentMemory < 16*1024*1024 {
 			return nil, fmt.Errorf("model requires at least 16GB of memory")
 		}
 	case ModelType30B, ModelType34B:
-		if totalResidentMemory < 32*1024*1024 {
+		if ggml.FileType().String() == "F16" && totalResidentMemory < 64*1024*1024 {
+			return nil, fmt.Errorf("F16 model requires at least 64GB of memory")
+		} else if totalResidentMemory < 32*1024*1024 {
 			return nil, fmt.Errorf("model requires at least 32GB of memory")
 		}
 	case ModelType65B:
-		if totalResidentMemory < 64*1024*1024 {
+		if ggml.FileType().String() == "F16" && totalResidentMemory < 128*1024*1024 {
+			return nil, fmt.Errorf("F16 model requires at least 128GB of memory")
+		} else if totalResidentMemory < 64*1024*1024 {
 			return nil, fmt.Errorf("model requires at least 64GB of memory")
 		}
 	}