use unsigned char for MPI IO

src/field_descriptor.cpp

@@ -86,6 +86,9 @@ field_descriptor::field_descriptor(
         tsubsizes[i] = this->subsizes[i];
         tstarts[i] = this->starts[i];
     }
+    tsizes[ndims-1] *= sizeof(float);
+    tsubsizes[ndims-1] *= sizeof(float);
+    tstarts[ndims-1] *= sizeof(float);
     if (this->mpi_dtype == MPI_COMPLEX8)
     {
         tsizes[ndims-1] *= 2;
@@ -160,7 +163,7 @@ field_descriptor::field_descriptor(
                 tsubsizes,
                 tstarts,
                 MPI_ORDER_C,
-                MPI_FLOAT,
+                MPI_UNSIGNED_CHAR,
                 &this->mpi_array_dtype);
         MPI_Type_commit(&this->mpi_array_dtype);
     }
@@ -210,15 +213,14 @@ field_descriptor::~field_descriptor()
 
 int field_descriptor::read(
         const char *fname,
-        void *buffer,
-        const char *datarep)
+        void *buffer)
 {
     if (this->subsizes[0] > 0)
     {
         MPI_Info info;
         MPI_Info_create(&info);
         MPI_File f;
-        int read_size = this->local_size;
+        int read_size = this->local_size*sizeof(float);
         char ffname[200];
         if (this->mpi_dtype == MPI_COMPLEX8)
             read_size *= 2;
@@ -233,15 +235,15 @@ int field_descriptor::read(
         MPI_File_set_view(
                 f,
                 0,
-                MPI_FLOAT,
+                MPI_UNSIGNED_CHAR,
                 this->mpi_array_dtype,
-                datarep,
+                "native",
                 info);
         MPI_File_read_all(
                 f,
                 buffer,
                 read_size,
-                MPI_FLOAT,
+                MPI_UNSIGNED_CHAR,
                 MPI_STATUS_IGNORE);
         MPI_File_close(&f);
     }
@@ -250,15 +252,14 @@ int field_descriptor::read(
 
 int field_descriptor::write(
         const char *fname,
-        void *buffer,
-        const char *datarep)
+        void *buffer)
 {
     if (this->subsizes[0] > 0)
     {
         MPI_Info info;
         MPI_Info_create(&info);
         MPI_File f;
-        int read_size = this->local_size;
+        int read_size = this->local_size*sizeof(float);
         char ffname[200];
         if (this->mpi_dtype == MPI_COMPLEX8)
             read_size *= 2;
@@ -273,15 +274,15 @@ int field_descriptor::write(
         MPI_File_set_view(
                 f,
                 0,
-                MPI_FLOAT,
+                MPI_UNSIGNED_CHAR,
                 this->mpi_array_dtype,
-                datarep,
+                "native",
                 info);
         MPI_File_write_all(
                 f,
                 buffer,
                 read_size,
-                MPI_FLOAT,
+                MPI_UNSIGNED_CHAR,
                 MPI_STATUS_IGNORE);
         MPI_File_close(&f);
     }

src/field_descriptor.hpp

@@ -57,12 +57,10 @@ class field_descriptor
          * */
         int read(
                 const char *fname,
-                void *buffer,
-                const char *datarep = "native");
+                void *buffer);
         int write(
                 const char *fname,
-                void *buffer,
-                const char *datarep = "native");
+                void *buffer);
 
         /* a function that generates the transposed descriptor.
          * don't forget to delete the result once you're done with it.
@@ -103,5 +101,17 @@ int fftwf_clip_zero_padding(
         field_descriptor *f,
         float *a);
 
+inline float btle(const float be)
+     {
+         float le;
+         char *befloat = (char *) & be;
+         char *lefloat = (char *) & le;
+         lefloat[0] = befloat[3];
+         lefloat[1] = befloat[2];
+         lefloat[2] = befloat[1];
+         lefloat[3] = befloat[0];
+         return le;
+     }
+
 #endif//FIELD_DESCRIPTOR
 

test3.ipynb

 {
  "metadata": {
   "name": "",
-  "signature": "sha256:41b656323632ba5dd67fcd6f67d6e62ab479be1edf0adc21548c493eb5da9b1d"
+  "signature": "sha256:966c6344a3d90cdf5a7423c96eebbfd82f41bd0e6556fcce769383cb4e93116c"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -63,8 +63,16 @@
      ],
      "language": "python",
      "metadata": {},
-     "outputs": [],
-     "prompt_number": 20
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stderr",
+       "text": [
+        "-c:15: RuntimeWarning: divide by zero encountered in true_divide\n"
+       ]
+      }
+     ],
+     "prompt_number": 2
     },
     {
      "cell_type": "code",
@@ -147,7 +155,7 @@
      "language": "python",
      "metadata": {},
      "outputs": [],
-     "prompt_number": 56
+     "prompt_number": 3
     },
     {
      "cell_type": "code",
@@ -200,7 +208,7 @@
      "language": "python",
      "metadata": {},
      "outputs": [],
-     "prompt_number": 52
+     "prompt_number": 5
     },
     {
      "cell_type": "code",
@@ -241,11 +249,11 @@
        "text": [
         "0.0\n",
         "distance is small\n",
-        "14.9705\n"
+        "14.4104\n"
        ]
       }
      ],
-     "prompt_number": 57
+     "prompt_number": 6
     },
     {
      "cell_type": "code",