diff --git a/README.md b/README.md
index bec6ca4..29365a2 100644
--- a/README.md
+++ b/README.md
@@ -3,14 +3,31 @@ Vulkan Flocking: compute and shading in one pipeline!
 
 **University of Pennsylvania, CIS 565: GPU Programming and Architecture, Project 6**
 
-* (TODO) YOUR NAME HERE
-  Windows 22, i7-2222 @ 2.22GHz 22GB, GTX 222 222MB (Moore 2222 Lab)
+* Xiang Deng
+* Tested on:  Windows 10-Home, i7-6700U @ 2.6GHz 16GB, GTX 1060 6GB (Personal Computer)
 
-  ### (TODO: Your README)
+![](img/e.gif) 
 
-  Include screenshots, analysis, etc. (Remember, this is public, so don't put
-  anything here that you don't want to share with the world.)
+* Analysis 
 
+* Q: Why do you think Vulkan expects explicit descriptors for things like
+generating pipelines and commands? HINT: this may relate to something in the
+comments about some components using pre-allocated GPU memory.
+* A: For efficiency, Vulkan uses pre-allocated command pool on GPU. Explicit descriptors is thus needed
+for preallocation prior to the run time (to avoid the overhead).
+
+* Q: Describe a situation besides flip-flop buffers in which you may need multiple
+descriptor sets to fit one descriptor layout.
+* A: When you need more descriptor set than two for the shader bindings, like normals, colors, etc. 
+* Q: What are some problems to keep in mind when using multiple Vulkan queues?
+  * take into consideration that different queues may be backed by different hardware
+  * take into consideration that the same buffer may be used across multiple queues
+* A: When diffrent queues are backed by different hardware, is some queue is only used by some hardware, it might sacrifice the performance of the hardware that
+   does not need it.
+     WHen multiple queues share the same buffer, we might run into racing problem.
+* Q: What is one advantage of using compute commands that can share data with a
+rendering pipeline?
+* A: "no need to do state tracking", no need to transfer data between computing and rendering over and over again.
 ### Credits
 
 * [Vulkan examples and demos](https://github.com/SaschaWillems/Vulkan) by [@SaschaWillems](https://github.com/SaschaWillems)
diff --git a/base/vulkanexamplebase.h b/base/vulkanexamplebase.h
index a30387e..2c59e84 100644
--- a/base/vulkanexamplebase.h
+++ b/base/vulkanexamplebase.h
@@ -50,7 +50,7 @@ class VulkanExampleBase
 	bool enableVSync = false;
 	// Device features enabled by the example
 	// If not set, no additional features are enabled (may result in validation layer errors)
-	VkPhysicalDeviceFeatures enabledFeatures = {};
+	VkPhysicalDeviceFeatures enabledFeatures ;
 	// fps timer (one second interval)
 	float fpsTimer = 0.0f;
 	// Create application wide Vulkan instance
diff --git a/data/shaders/computeparticles/particle.comp b/data/shaders/computeparticles/particle.comp
index b7dc2f7..9230a17 100644
--- a/data/shaders/computeparticles/particle.comp
+++ b/data/shaders/computeparticles/particle.comp
@@ -58,6 +58,48 @@ void main()
 		vec2 vPos = particlesA[index].pos.xy;
     vec2 vVel = particlesA[index].vel.xy;
 
+
+
+	vec2   pvj = vec2(0.0, 0.0); //perceived center of mass v
+	vec2   pcj = vec2 (0.0, 0.0); //perceived center of mass 
+	vec2 v2  = vec2(0.0, 0.0); 
+	vec2 v3 =vec2 (0.0, 0.0);  
+	
+
+	vec2 pos;
+	vec2 vel;
+	float cnt1=0; float cnt2=0; float cnt3=0;
+	for (int i=0; i< ubo.particleCount; i++){
+		if (i!= index) 
+		{
+			pos = particlesA[i].pos.xy;
+			vel = particlesA[i].vel.xy;
+
+			float d = distance(pos, vPos);
+			// Rule 1: boids fly towards their local perceived center of mass, which excludes themselves
+			if (d < ubo.rule1Distance){
+				pcj = pcj  +  pos;
+				cnt1 ++;
+			}
+			// Rule 2: boids try to stay a distance d away from each other
+			if (d < ubo.rule2Distance){
+				v2 = v2 - (pos-vPos);
+			}
+			// Rule 3: boids try to match the speed of surrounding boids
+			if (d < ubo.rule3Distance ){
+				pvj = pvj + vel;
+				cnt3 ++;
+			} 
+		}
+	}   	 
+	v3=pvj; 
+	vec2 val = vec2(0.0,0.0);
+	if (cnt1!=0){
+		val+=(pcj/cnt1 - vPos) * ubo.rule1Scale;
+	}
+	vVel +=v3 * ubo.rule3Scale+v2* ubo.rule2Scale;
+
+
 		// clamp velocity for a more pleasing simulation.
 		vVel = normalize(vVel) * clamp(length(vVel), 0.0, 0.1);
 
diff --git a/data/shaders/computeparticles/particle.comp.spv b/data/shaders/computeparticles/particle.comp.spv
index 059ab59..0a9d022 100644
Binary files a/data/shaders/computeparticles/particle.comp.spv and b/data/shaders/computeparticles/particle.comp.spv differ
diff --git a/img/e.gif b/img/e.gif
new file mode 100644
index 0000000..19ebbbf
Binary files /dev/null and b/img/e.gif differ
diff --git a/vulkanBoids/vulkanBoids.cpp b/vulkanBoids/vulkanBoids.cpp
index 9b2f122..54620a8 100644
--- a/vulkanBoids/vulkanBoids.cpp
+++ b/vulkanBoids/vulkanBoids.cpp
@@ -28,16 +28,16 @@
 
 #define VERTEX_BUFFER_BIND_ID 0
 #define ENABLE_VALIDATION true // LOOK: toggle Vulkan validation layers. These make debugging much easier!
-#define PARTICLE_COUNT 4 * 1024 // LOOK: change particle count here
+#define PARTICLE_COUNT 2 * 1024 // LOOK: change particle count here
 
 // LOOK: constants for the boids algorithm. These will be passed to the GPU compute part of the assignment
 // using a Uniform Buffer. These parameters should yield a stable and pleasing simulation for an
 // implementation based off the code here: http://studio.sketchpad.cc/sp/pad/view/ro.9cbgCRcgbPOI6/rev.23
-#define RULE1DISTANCE 0.1f // cohesion
-#define RULE2DISTANCE 0.05f // separation
-#define RULE3DISTANCE 0.05f // alignment
-#define RULE1SCALE 0.02f
-#define RULE2SCALE 0.05f
+#define RULE1DISTANCE 0.025f // cohesion
+#define RULE2DISTANCE 0.013f // separation
+#define RULE3DISTANCE 0.025f // alignment
+#define RULE1SCALE 0.001f
+#define RULE2SCALE 0.01f
 #define RULE3SCALE 0.01f
 
 class VulkanExample : public VulkanExampleBase
@@ -158,6 +158,7 @@ class VulkanExample : public VulkanExampleBase
 		{
 			particle.pos = glm::vec2(rDistribution(rGenerator), rDistribution(rGenerator));
 			// TODO: add randomized velocities with a slight scale here, something like 0.1f.
+			particle.vel = glm::vec2(rDistribution(rGenerator), rDistribution(rGenerator));
 		}
 
 		VkDeviceSize storageBufferSize = particleBuffer.size() * sizeof(Particle);
@@ -244,7 +245,7 @@ class VulkanExample : public VulkanExampleBase
 			VERTEX_BUFFER_BIND_ID,
 			1,
 			VK_FORMAT_R32G32_SFLOAT,
-			offsetof(Particle, pos)); // TODO: change this so that we can color the particles based on velocity.
+			offsetof(Particle, vel)); // TODO +: change this so that we can color the particles based on velocity.
 
 		// vertices.inputState encapsulates everything we need for these particular buffers to
 		// interface with the graphics pipeline.
@@ -540,13 +541,36 @@ class VulkanExample : public VulkanExampleBase
 			compute.descriptorSets[0],
 			VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
 			2,
-			&compute.uniformBuffer.descriptor)
+			&compute.uniformBuffer.descriptor),
 
 			// TODO: write the second descriptorSet, using the top for reference.
 			// We want the descriptorSets to be used for flip-flopping:
 			// on one frame, we use one descriptorSet with the compute pass,
 			// on the next frame, we use the other.
 			// What has to be different about how the second descriptorSet is written here?
+
+			//+
+			// Binding 0 : Particle position storage buffer
+			vkTools::initializers::writeDescriptorSet(
+			compute.descriptorSets[1], // LOOK: which descriptor set to write to?
+			VK_DESCRIPTOR_TYPE_STORAGE_BUFFER,
+			0, // LOOK: which binding in the descriptor set Layout?
+			&compute.storageBufferB.descriptor), // LOOK: which SSBO?
+
+			// Binding 1 : Particle position storage buffer
+			vkTools::initializers::writeDescriptorSet(
+			compute.descriptorSets[1],
+			VK_DESCRIPTOR_TYPE_STORAGE_BUFFER,
+			1,
+			&compute.storageBufferA.descriptor),
+
+			// Binding 2 : Uniform buffer
+			vkTools::initializers::writeDescriptorSet(
+			compute.descriptorSets[1],
+			VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
+			2,
+			&compute.uniformBuffer.descriptor)
+
 		};
 
 		vkUpdateDescriptorSets(device, static_cast<uint32_t>(computeWriteDescriptorSets.size()), computeWriteDescriptorSets.data(), 0, NULL);
@@ -590,6 +614,9 @@ class VulkanExample : public VulkanExampleBase
 		// We also want to flip what SSBO we draw with in the next
 		// pass through the graphics pipeline.
 		// Feel free to use std::swap here. You should need it twice.
+
+		//+
+		std::swap(compute.descriptorSets[0], compute.descriptorSets[1]);
 	}
 
 	// Record command buffers for drawing using the graphics pipeline
@@ -639,7 +666,10 @@ class VulkanExample : public VulkanExampleBase
 			// How does this influence flip-flopping in draw()?
 			// Try drawing with storageBufferA instead of storageBufferB. What happens? Why?
 			VkDeviceSize offsets[1] = { 0 };
-			vkCmdBindVertexBuffers(drawCmdBuffers[i], VERTEX_BUFFER_BIND_ID, 1, &compute.storageBufferB.buffer, offsets);
+			//+
+			vkCmdBindVertexBuffers(drawCmdBuffers[i], VERTEX_BUFFER_BIND_ID, 1, &compute.storageBufferA.buffer, offsets);
+
+			//vkCmdBindVertexBuffers(drawCmdBuffers[i], VERTEX_BUFFER_BIND_ID, 1, &compute.storageBufferB.buffer, offsets);
 			vkCmdDraw(drawCmdBuffers[i], PARTICLE_COUNT, 1, 0, 0);
 
 			vkCmdEndRenderPass(drawCmdBuffers[i]);