add .reset_cache()

include/armadillo_bits/SpMat_bones.hpp

@@ -360,6 +360,7 @@ class SpMat : public SpBase< eT, SpMat<eT> >
   inline const SpMat& sprandn(const SizeMat& s,                         const double density);
   
   inline void reset();
+  inline void reset_cache();
   
   //! don't use this unless you're writing internal Armadillo code
   inline void reserve(const uword in_rows, const uword in_cols, const uword new_n_nonzero);

include/armadillo_bits/SpMat_meat.hpp

@@ -4501,6 +4501,45 @@ SpMat<eT>::reset()
 
 
 
+template<typename eT>
+inline
+void
+SpMat<eT>::reset_cache()
+  {
+  arma_extra_debug_sigprint();
+  
+  sync_csc();
+  
+  #if defined(ARMA_USE_OPENMP)
+    {
+    #pragma omp critical (arma_SpMat_cache)
+      {
+      cache.reset();
+      
+      sync_state = 0;
+      }
+    }
+  #elif (!defined(ARMA_DONT_USE_STD_MUTEX))
+    {
+    cache_mutex.lock();
+    
+    cache.reset();
+    
+    sync_state = 0;
+    
+    cache_mutex.unlock();
+    }
+  #else
+    {
+    cache.reset();
+    
+    sync_state = 0;
+    }
+  #endif
+  }
+
+
+
 template<typename eT>
 inline
 void