handle partially quantized models (#76)

* handle partially quantized models

- fix for #53 #71 #69 #74
- in order to test the models
	- I added a default prompt of an appropriate form
	- while working on the model configuration also added additional stop tokens (#74)
- fixed the repetitionPenalty code (#71)

Tools/llm-tool/LLMTool.swift

@@ -44,7 +44,7 @@ struct GenerateArguments: ParsableArguments {
         help:
             "The message to be processed by the model.  Use @path,@path to load from files, e.g. @/tmp/prompt.txt"
     )
-    var prompt = "compare python and swift"
+    var prompt: String?
 
     @Option(name: .shortAndLong, help: "Maximum number of tokens to generate")
     var maxTokens = 100
@@ -73,7 +73,8 @@ struct GenerateArguments: ParsableArguments {
             repetitionContextSize: repetitionContextSize)
     }
 
-    func resolvePrompt() throws -> String {
+    func resolvePrompt(configuration: ModelConfiguration) throws -> String {
+        let prompt = self.prompt ?? configuration.defaultPrompt
         if prompt.hasPrefix("@") {
             let names = prompt.split(separator: ",").map { String($0.dropFirst()) }
             return try names.map { try String(contentsOfFile: $0) }.joined(separator: "\n")
@@ -87,14 +88,17 @@ struct GenerateArguments: ParsableArguments {
     ) {
         MLXRandom.seed(seed)
 
-        let prompt = try resolvePrompt()
+        let prompt = try resolvePrompt(configuration: configuration)
         let preparedPrompt = configuration.prepare(prompt: prompt)
         let promptTokens = tokenizer.encode(text: preparedPrompt)
 
         return (prompt, promptTokens)
     }
 
-    func generate(promptTokens: [Int], model: LLMModel, tokenizer: Tokenizer) async
+    func generate(
+        promptTokens: [Int], model: LLMModel, tokenizer: Tokenizer,
+        extraEOSTokens: Set<String>? = nil
+    ) async
         -> GenerateResult
     {
         // track how much we have printed
@@ -102,7 +106,7 @@ struct GenerateArguments: ParsableArguments {
 
         return await LLM.generate(
             promptTokens: promptTokens, parameters: generateParameters,
-            model: model, tokenizer: tokenizer
+            model: model, tokenizer: tokenizer, extraEOSTokens: extraEOSTokens
         ) { tokens in
 
             // print any new parts of the string
@@ -226,7 +230,8 @@ struct EvaluateCommand: AsyncParsableCommand {
         }
 
         let result = await generate.generate(
-            promptTokens: promptTokens, model: model, tokenizer: tokenizer)
+            promptTokens: promptTokens, model: model, tokenizer: tokenizer,
+            extraEOSTokens: modelConfiguration.extraEOSTokens)
         print()
 
         if !generate.quiet {