get rid of some warnings

bfps/cpp/field.hpp

@@ -266,9 +266,9 @@ class field
         }
 
         ptrdiff_t get_rindex_from_global(const ptrdiff_t in_global_x, const ptrdiff_t in_global_y, const ptrdiff_t in_global_z) const {
-            assert(in_global_x >= 0 && in_global_x < this->rlayout->sizes[2]);
-            assert(in_global_y >= 0 && in_global_y < this->rlayout->sizes[1]);
-            assert(in_global_z >= 0 && in_global_z < this->rlayout->sizes[0]);
+            assert(in_global_x >= 0 && in_global_x < ptrdiff_t(this->rlayout->sizes[2]));
+            assert(in_global_y >= 0 && in_global_y < ptrdiff_t(this->rlayout->sizes[1]));
+            assert(in_global_z >= 0 && in_global_z < ptrdiff_t(this->rlayout->sizes[0]));
             return get_rindex(in_global_x - this->rlayout->starts[2],
                               in_global_y - this->rlayout->starts[1],
                               in_global_z - this->rlayout->starts[0]);

bfps/cpp/field_binary_IO.cpp

@@ -49,7 +49,7 @@ field_binary_IO<rnumber, fr, fc>::field_binary_IO(
     tsizes.resize(ndim(fc));
     tsubsizes.resize(ndim(fc));
     tstarts.resize(ndim(fc));
-    for (int i=0; i<ndim(fc); i++)
+    for (int i=0; i<int(ndim(fc)); i++)
     {
         tsizes[i] = int(this->sizes[i]);
         tsubsizes[i] = int(this->subsizes[i]);

bfps/cpp/kspace.cpp

@@ -186,7 +186,7 @@ int kspace<be, dt>::store(hid_t stat_file)
     space = H5Dget_space(dset);
     H5Sget_simple_extent_dims(space, dims, NULL);
     H5Sclose(space);
-    if (this->nshells != dims[0])
+    if (this->nshells != int(dims[0]))
     {
         DEBUG_MSG(
                 "ERROR: computed nshells %d not equal to data file nshells %d\n",

bfps/cpp/vorticity_equation.cpp

@@ -75,7 +75,7 @@ void vorticity_equation<rnumber, be>::update_checkpoint()
                     H5P_DEFAULT);
             H5Gclose(group_id);
             H5Fclose(fid);
-            if ((fields_stored >= this->checkpoints_per_file) &&
+            if ((int(fields_stored) >= this->checkpoints_per_file) &&
                 !dset_exists)
                 this->checkpoint++;
         }