Create attributes as scalars, fix MatrixMarket FP printing.

Author: BenBrock

examples/check_equivalence.c

@@ -53,7 +53,8 @@ int check_array_equivalence(bsp_array_t array1, bsp_array_t array2) {
       bsp_array_read(array2, i, value2);
 
       if (value1 != value2) {
-        fprintf(stderr, "Array values are not equal.\n");
+        fprintf(stderr, "Array values are not equal. (%zu != %zu)\n", value1,
+                value2);
         return 4;
       }
     } else if (mm_type1 == BSP_MM_REAL) {
@@ -62,7 +63,11 @@ int check_array_equivalence(bsp_array_t array1, bsp_array_t array2) {
       bsp_array_read(array2, i, value2);
 
       if (value1 != value2) {
-        fprintf(stderr, "Array values are not equal.\n");
+        fprintf(stderr,
+                "Array values are not equal. (%.17lg + i%.17lg != %.17lg + "
+                "i%.17lg)\n",
+                __real__ value1, __imag__ value1, __real__ value2,
+                __imag__ value2);
         return 4;
       }
     } else if (mm_type1 == BSP_MM_COMPLEX) {

include/binsparse/hdf5_wrapper.h

@@ -96,8 +96,7 @@ void bsp_write_attribute(hid_t f, char* label, char* string) {
   hid_t strtype = H5Tcopy(H5T_C_S1);
   H5Tset_size(strtype, strlen(string));
   H5Tset_cset(strtype, H5T_CSET_UTF8);
-  hsize_t size = 1;
-  hid_t dataspace = H5Screate_simple(1, &size, H5P_DEFAULT);
+  hid_t dataspace = H5Screate(H5S_SCALAR);
 
   hid_t attribute =
       H5Acreate2(f, label, strtype, dataspace, H5P_DEFAULT, H5P_DEFAULT);

include/binsparse/matrix_market/matrix_market_write.h

@@ -76,16 +76,18 @@ void bsp_mmwrite(char* file_path, bsp_matrix_t matrix) {
         bsp_array_read(matrix.indices_0, count, i);
         bsp_array_read(matrix.indices_1, count, j);
         bsp_array_read(matrix.values, count, value);
-        fprintf(f, "%zu %zu %lf\n", i + 1, j + 1, value);
+        fprintf(f, "%zu %zu %.17lg\n", i + 1, j + 1, value);
       } else if (mm_type == BSP_MM_COMPLEX) {
+        // TODO: use Tim Davis' trick from SuiteSparse to limit the number of
+        //       digits printed without reducing accuracy.
         size_t i, j;
         double _Complex value;
         bsp_array_read(matrix.indices_0, count, i);
         bsp_array_read(matrix.indices_1, count, j);
         bsp_array_read(matrix.values, count, value);
         double real_value = 1.0 * value;
         double complex_value = 1j * value;
-        fprintf(f, "%zu %zu %lf %lf\n", i + 1, j + 1, real_value,
+        fprintf(f, "%zu %zu %.17lg %.17lg\n", i + 1, j + 1, real_value,
                 complex_value);
       } else {
         assert(false);