3 files changed, 23 insertions, 9 deletions
diff --git a/utils/fast_sparse_vector.h b/utils/fast_sparse_vector.h
index 4aae2039..9d72cb87 100644
--- a/utils/fast_sparse_vector.h
+++ b/utils/fast_sparse_vector.h
@@ -235,6 +235,13 @@ class FastSparseVector {
     }
     return *this;
   }
+  FastSparseVector<T> erase_zeros(const T& EPSILON = 1e-4) const {
+    FastSparseVector<T> o;
+    for (const_iterator it = begin(); it != end(); ++it) {
+      if (fabs(it->second) > EPSILON) o.set_value(it->first, it->second);
+    }
+    return o;
+  }
   const_iterator begin() const {
     return const_iterator(*this, false);
   }
@@ -344,15 +351,9 @@ const FastSparseVector<T> operator+(const FastSparseVector<T>& x, const FastSpar
 
 template <typename T>
 const FastSparseVector<T> operator-(const FastSparseVector<T>& x, const FastSparseVector<T>& y) {
-  if (x.size() > y.size()) {
-    FastSparseVector<T> res(x);
-    res -= y;
-    return res;
-  } else {
-    FastSparseVector<T> res(y);
-    res -= x;
-    return res;
-  }
+  FastSparseVector<T> res(x);
+  res -= y;
+  return res;
 }
 
 template <class T>
diff --git a/utils/filelib.cc b/utils/filelib.cc
index 79ad2847..a0969b1a 100644
--- a/utils/filelib.cc
+++ b/utils/filelib.cc
@@ -20,3 +20,15 @@ bool DirectoryExists(const string& dir) {
   return false;
 }
 
+void MkDirP(const string& dir) {
+  if (DirectoryExists(dir)) return;
+  if (mkdir(dir.c_str(), 0777)) {
+    perror(dir.c_str());
+    abort();
+  }
+  if (chmod(dir.c_str(), 07777)) {
+    perror(dir.c_str());
+    abort();
+  }
+}
+
diff --git a/utils/filelib.h b/utils/filelib.h
index dda98671..a8622246 100644
--- a/utils/filelib.h
+++ b/utils/filelib.h
@@ -12,6 +12,7 @@
 
 bool FileExists(const std::string& file_name);
 bool DirectoryExists(const std::string& dir_name);
+void MkDirP(const std::string& dir_name);
 
 // reads from standard in if filename is -
 // uncompresses if file ends with .gz