Run sift test from separate directory

Author: Dmitry Yashunin

README.md

@@ -242,13 +242,15 @@ Contributions are highly welcome!
 Please make pull requests against the `develop` branch.
 
 ### 200M SIFT test reproduction 
-To download and extract the bigann dataset:
+To download and extract the bigann dataset (from root directory):
 ```bash
 python3 download_bigann.py
 ```
 To compile:
 ```bash
-cmake .
+mkdir build
+cd build
+cmake ..
 make all
 ```
 

sift_1b.cpp

@@ -242,11 +242,11 @@ void sift_test1B() {
     size_t vecdim = 128;
     char path_index[1024];
     char path_gt[1024];
-    char *path_q = "bigann/bigann_query.bvecs";
-    char *path_data = "bigann/bigann_base.bvecs";
+    char *path_q = "../bigann/bigann_query.bvecs";
+    char *path_data = "../bigann/bigann_base.bvecs";
     sprintf(path_index, "sift1b_%dm_ef_%d_M_%d.bin", subset_size_milllions, efConstruction, M);
 
-    sprintf(path_gt, "bigann/gnd/idx_%dM.ivecs", subset_size_milllions);
+    sprintf(path_gt, "../bigann/gnd/idx_%dM.ivecs", subset_size_milllions);
 
 
     unsigned char *massb = new unsigned char[vecdim];