LlmDemo LoRA, PTE+PTD support

llm/android/LlamaDemo/app/build.gradle.kts

@@ -268,14 +268,14 @@ dependencies {
   if (useLocalAar == true) {
     implementation(files("libs/executorch.aar"))
   } else {
-    implementation("org.pytorch:executorch-android:1.0.1")
+    implementation("org.pytorch:executorch-android:1.1.0")
     // https://mvnrepository.com/artifact/org.pytorch/executorch-android-qnn
     // Uncomment this to enable QNN
-    // implementation("org.pytorch:executorch-android-qnn:1.0.1")
+    // implementation("org.pytorch:executorch-android-qnn:1.1.0")
 
     // https://mvnrepository.com/artifact/org.pytorch/executorch-android-vulkan
     // uncomment to enable vulkan
-    // implementation("org.pytorch:executorch-android-vulkan:1.0.1")
+    // implementation("org.pytorch:executorch-android-vulkan:1.1.0")
   }
   implementation("com.google.android.material:material:1.12.0")
   implementation("androidx.activity:activity:1.9.0")

llm/android/LlamaDemo/app/src/main/java/com/example/executorchllamademo/ModelConfiguration.kt

@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.example.executorchllamademo
+
+/**
+ * Represents a single PTE model configuration.
+ * Multiple ModelConfigurations can share the same PTD (data path) file for LoRA support.
+ */
+data class ModelConfiguration(
+    val id: String = "",
+    val modelFilePath: String = "",
+    val tokenizerFilePath: String = "",
+    val modelType: ModelType = ModelType.LLAMA_3,
+    val backendType: BackendType = BackendType.XNNPACK,
+    val temperature: Double = ModuleSettings.DEFAULT_TEMPERATURE,
+    val displayName: String = "",
+    val adapterFilePaths: List<String> = emptyList()
+) {
+    companion object {
+        fun create(
+            modelFilePath: String,
+            tokenizerFilePath: String,
+            modelType: ModelType,
+            backendType: BackendType,
+            temperature: Double
+        ): ModelConfiguration {
+            return ModelConfiguration(
+                id = generateId(modelFilePath),
+                modelFilePath = modelFilePath,
+                tokenizerFilePath = tokenizerFilePath,
+                modelType = modelType,
+                backendType = backendType,
+                temperature = temperature,
+                displayName = extractDisplayName(modelFilePath)
+            )
+        }
+
+        private fun generateId(modelFilePath: String): String {
+            return modelFilePath.hashCode().toString()
+        }
+
+        private fun extractDisplayName(filePath: String): String {
+            if (filePath.isEmpty()) return ""
+            return filePath.substringAfterLast('/')
+        }
+    }
+
+    fun isValid(): Boolean {
+        return modelFilePath.isNotEmpty() && tokenizerFilePath.isNotEmpty()
+    }
+
+    fun withModelFilePath(path: String): ModelConfiguration {
+        return copy(
+            modelFilePath = path,
+            id = generateId(path),
+            displayName = extractDisplayName(path)
+        )
+    }
+}

llm/android/LlamaDemo/app/src/main/java/com/example/executorchllamademo/ModuleSettings.kt

@@ -10,8 +10,10 @@ package com.example.executorchllamademo
 
 /**
  * Holds module-specific settings for the current model/tokenizer configuration.
+ * Supports both legacy single-model and multi-model configurations for LoRA support.
  */
 data class ModuleSettings(
+    // Legacy single-model fields (kept for backward compatibility)
     val modelFilePath: String = "",
     val tokenizerFilePath: String = "",
     val dataPath: String = "",
@@ -21,22 +23,135 @@ data class ModuleSettings(
     val modelType: ModelType = DEFAULT_MODEL,
     val backendType: BackendType = DEFAULT_BACKEND,
     val isClearChatHistory: Boolean = false,
-    val isLoadModel: Boolean = false
+    val isLoadModel: Boolean = false,
+
+    // LoRA mode toggle - when enabled, allows multiple model selection
+    val isLoraMode: Boolean = false,
+
+    // Foundation PTD path - shared base weights for all LoRA models
+    val foundationDataPath: String = "",
+
+    // Multi-model support fields (used when isLoraMode is true)
+    val models: List<ModelConfiguration> = emptyList(),
+    val activeModelId: String = "",
+    val sharedDataPath: String = "",
+    val foundationModelType: ModelType = ModelType.LLAMA_3
 ) {
+    /**
+     * Gets the effective model type, considering multi-model configuration.
+     */
+    fun getEffectiveModelType(): ModelType {
+        val activeModel = getActiveModel()
+        return activeModel?.modelType ?: modelType
+    }
+
     fun getFormattedSystemPrompt(): String {
-        return PromptFormat.getSystemPromptTemplate(modelType)
+        return PromptFormat.getSystemPromptTemplate(getEffectiveModelType())
             .replace(PromptFormat.SYSTEM_PLACEHOLDER, systemPrompt)
     }
 
     fun getFormattedUserPrompt(prompt: String, thinkingMode: Boolean): String {
+        val effectiveType = getEffectiveModelType()
         return userPrompt
             .replace(PromptFormat.USER_PLACEHOLDER, prompt)
             .replace(
                 PromptFormat.THINKING_MODE_PLACEHOLDER,
-                PromptFormat.getThinkingModeToken(modelType, thinkingMode)
+                PromptFormat.getThinkingModeToken(effectiveType, thinkingMode)
             )
     }
 
+    /**
+     * Gets the active model configuration if using multi-model mode.
+     */
+    fun getActiveModel(): ModelConfiguration? {
+        if (models.isEmpty() || activeModelId.isEmpty()) return null
+        return models.find { it.id == activeModelId }
+    }
+
+    /**
+     * Gets a model configuration by ID.
+     */
+    fun getModelById(modelId: String): ModelConfiguration? {
+        return models.find { it.id == modelId }
+    }
+
+    /**
+     * Gets the effective foundation data path for LoRA mode.
+     * Priority: foundationDataPath > sharedDataPath > dataPath
+     */
+    fun getEffectiveDataPath(): String {
+        return foundationDataPath.ifEmpty { sharedDataPath.ifEmpty { dataPath } }
+    }
+
+    /**
+     * Checks if there are multiple models configured.
+     */
+    fun hasMultipleModels(): Boolean = models.size > 1
+
+    /**
+     * Checks if any models are configured.
+     */
+    fun hasModels(): Boolean = models.isNotEmpty()
+
+    /**
+     * Adds a model to the list. If a model with the same ID exists, it's replaced.
+     * If this is the first model, it becomes the active model.
+     */
+    fun addModel(model: ModelConfiguration): ModuleSettings {
+        val existingIndex = models.indexOfFirst { it.id == model.id }
+        val newModels = if (existingIndex >= 0) {
+            models.toMutableList().apply { this[existingIndex] = model }
+        } else {
+            models + model
+        }
+        val newActiveId = if (models.isEmpty()) model.id else activeModelId
+        return copy(models = newModels, activeModelId = newActiveId)
+    }
+
+    /**
+     * Removes a model by ID. If the active model is removed, selects another.
+     */
+    fun removeModel(modelId: String): ModuleSettings {
+        val newModels = models.filter { it.id != modelId }
+        val newActiveId = if (activeModelId == modelId) {
+            newModels.firstOrNull()?.id ?: ""
+        } else {
+            activeModelId
+        }
+        return copy(models = newModels, activeModelId = newActiveId)
+    }
+
+    /**
+     * Sets the active model by ID.
+     */
+    fun setActiveModel(modelId: String): ModuleSettings {
+        return copy(activeModelId = modelId)
+    }
+
+    /**
+     * Migrates legacy single-model settings to multi-model format.
+     */
+    fun migrateToMultiModel(): ModuleSettings {
+        if (models.isNotEmpty()) return this
+
+        // Only migrate if there's a valid legacy model configuration
+        if (modelFilePath.isEmpty() || tokenizerFilePath.isEmpty()) return this
+
+        val legacyModel = ModelConfiguration.create(
+            modelFilePath = modelFilePath,
+            tokenizerFilePath = tokenizerFilePath,
+            modelType = modelType,
+            backendType = backendType,
+            temperature = temperature
+        )
+
+        return copy(
+            models = listOf(legacyModel),
+            activeModelId = legacyModel.id,
+            sharedDataPath = dataPath
+        )
+    }
+
     companion object {
         const val DEFAULT_TEMPERATURE = 0.0
         val DEFAULT_MODEL = ModelType.LLAMA_3

llm/android/LlamaDemo/app/src/main/java/com/example/executorchllamademo/ui/components/ModelListItem.kt

@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.example.executorchllamademo.ui.components
+
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.RadioButton
+import androidx.compose.material3.RadioButtonDefaults
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import com.example.executorchllamademo.ModelConfiguration
+import com.example.executorchllamademo.ui.theme.LocalAppColors
+
+/**
+ * A composable that displays a single model configuration in a list.
+ * Shows the model name, type, backend, and tokenizer, with a radio button
+ * for selection and a remove button.
+ */
+@Composable
+fun ModelListItem(
+    model: ModelConfiguration,
+    isActive: Boolean,
+    onSelect: () -> Unit,
+    onRemove: () -> Unit,
+    modifier: Modifier = Modifier
+) {
+    val appColors = LocalAppColors.current
+
+    Row(
+        modifier = modifier
+            .fillMaxWidth()
+            .clickable(onClick = onSelect)
+            .padding(horizontal = 12.dp, vertical = 8.dp),
+        verticalAlignment = Alignment.CenterVertically
+    ) {
+        RadioButton(
+            selected = isActive,
+            onClick = onSelect,
+            colors = RadioButtonDefaults.colors(
+                selectedColor = appColors.settingsText,
+                unselectedColor = appColors.settingsSecondaryText
+            )
+        )
+
+        Spacer(modifier = Modifier.width(8.dp))
+
+        Column(
+            modifier = Modifier.weight(1f)
+        ) {
+            // Model name (display name from file path)
+            Text(
+                text = model.displayName.ifEmpty { "Unknown Model" },
+                color = appColors.settingsText,
+                fontSize = 16.sp,
+                fontWeight = FontWeight.Bold,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis
+            )
+
+            // Tokenizer name
+            val tokenizerName = model.tokenizerFilePath.substringAfterLast('/').ifEmpty { "No tokenizer" }
+            Text(
+                text = tokenizerName,
+                color = appColors.settingsSecondaryText.copy(alpha = 0.7f),
+                fontSize = 11.sp,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis
+            )
+        }
+
+        IconButton(
+            onClick = onRemove,
+            modifier = Modifier.size(40.dp)
+        ) {
+            Icon(
+                imageVector = Icons.Filled.Close,
+                contentDescription = "Remove model",
+                tint = Color(0xFFFF6666)
+            )
+        }
+    }
+}