a

assignments/04/km_cuda.cu

@@ -190,7 +190,7 @@ int main(int argc, char **argv) {
 
 #pragma region Iteration
   int it = 0;
-  while (*dirtyBit) {
+  for (int it=0;it < 20 && *dirtyBit; ++it) {
     printf("Iteration %d (dirty=%d)\n", it, *dirtyBit);
 
     // Update each centroid to be the average coordinate of all contained data
@@ -219,8 +219,6 @@ int main(int argc, char **argv) {
     assignClosestCentroid<<<N, 1>>>(N, num_clusters, dirtyBit,
                                     centroidDistances, clusterMap);
     CUDACHECK(cudaDeviceSynchronize());
-
-    it++;
   }
 #pragma endregion
 

assignments/04/report.typ

@@ -2,7 +2,7 @@
 
 Michael Zhang \<zhan4854\@umn.edu\>
 
-1. A short description of how you went about parallelizing the k-means algorithm. You should include how you decomposed the problem and why, i.e., what were the tasks being parallelized.
+1. *A short description of how you went about parallelizing the k-means algorithm. You should include how you decomposed the problem and why, i.e., what were the tasks being parallelized.*
 
   My parallelized program included the following procedures:
 
@@ -16,12 +16,22 @@ Michael Zhang \<zhan4854\@umn.edu\>
 
   I tried to make sure every thread is computing approximately one single for-loop's worth of data, most of the time over the $d$ axis
 
-2. Give details about how many elements and how the computations in your kernels are handled by a thread.
+2. *Give details about how many elements and how the computations in your kernels are handled by a thread.*
 
-  Threads are dynamically allocated 
+  I used the dynamic thread allocation method based on the size of the data.
 
-3. Ensure you include details about the thread hierarchy, i.e., whether the threads are organized in a 1D, 2D, or, 3D fashion in a thread-block, and whether the thread-blocks are arranged 1D, 2D, or, 3D grid. NOTE: If you choose to write CUDA kernels where the number of thread blocks is determined dynamically by the program during runtime, then send -1 as the input argument for the number of thread blocks to the invocation. In your program, use -1 as a flag to indicate that the number of thread blocks will need to be computed during runtime.
+  For most of the kernels, the computation is very simple: perform a row-reduction into a different array. Since all the accesses are disjoint, I don't synchronize between threads.
 
-4. You need to perform a parameter study in order to determine how the number of elements processed by a thread and the size of a thread-block, i.e., the \# threads in a block, affect the performance of your algorithm. Your writeup should contain some results showing the runtime that you obtained for different choices.
+  However, for averaging the datapoints, I unfortunately need to run a $N times K times D$ operation that involves a sum reduction. I tried using a tree-based approach after doing some bitwise math to avoid the conditional of whether it's in the same class, but the plain approach is simpler and I did not get the other one to work.
 
-5. You should include results on the 'large_cpd.txt' dataset with 256, 512, and 1024 clusters.
+3. *Ensure you include details about the thread hierarchy, i.e., whether the threads are organized in a 1D, 2D, or, 3D fashion in a thread-block, and whether the thread-blocks are arranged 1D, 2D, or, 3D grid. NOTE: If you choose to write CUDA kernels where the number of thread blocks is determined dynamically by the program during runtime, then send -1 as the input argument for the number of thread blocks to the invocation. In your program, use -1 as a flag to indicate that the number of thread blocks will need to be computed during runtime.*
+
+  I used a 1D thread hierarchy. This is because all my accesses are already basically along the "good" axis, so I'm not doing any strides along other dimensions.
+
+4. *You need to perform a parameter study in order to determine how the number of elements processed by a thread and the size of a thread-block, i.e., the \# threads in a block, affect the performance of your algorithm. Your writeup should contain some results showing the runtime that you obtained for different choices.*
+
+5. *You should include results on the 'large_cpd.txt' dataset with 256, 512, and 1024 clusters.*
+
+  - 256: 26.8258s
+  - 512: 62.1212s
+  - 1024: 163.4022s

assignments/04/run.sh

@@ -1,5 +1,12 @@
 set -euo pipefail
 HOST="zhan4854@csel-cuda-02.cselabs.umn.edu"
 rsync -azPr --exclude 'large_cpd.txt' . $HOST:~/hwk4
-ssh $HOST bash -c 'set -euo pipefail; module load soft/cuda/local; module initadd soft/cuda/local; cd hwk4; make clean; make; ls; ./km_cuda ./dataset/small_gaussian.txt 2 64 128'
-rsync -azPr --exclude 'large_cpd.txt' zhan4854@csel-cuda-02.cselabs.umn.edu:~/hwk4/ .
+
+CLUSTERS=${1:-512}
+BLOCKS=-1
+THREADS=-1
+DATAFILE="large_cpd.txt"
+# DATAFILE="small_gaussian.txt"
+
+ssh $HOST bash -c "set -euo pipefail; module load soft/cuda/local; module initadd soft/cuda/local; cd hwk4; make clean; make; ls; ./km_cuda ./dataset/$DATAFILE $CLUSTERS 64 128"
+rsync -qazPr --exclude 'large_cpd.txt' zhan4854@csel-cuda-02.cselabs.umn.edu:~/hwk4/ .