examples/c_api/writing_dense_sparse.c

/**
 * @file   writing_dense_sparse.c
 *
 * @section LICENSE
 *
 * The MIT License
 *
 * @copyright Copyright (c) 2018-2021 TileDB, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @section DESCRIPTION
 *
 * When run, this program will create a simple 2D dense array, write some sparse
 * cells to it in a way that some space is empty, and read the entire array data
 * back.
 */

#include <stdio.h>
#include <stdlib.h>
#include <tiledb/tiledb.h>

// Name of array.
const char* array_name = "writing_dense_sparse_array";

void create_array() {
  // Create TileDB context
  tiledb_ctx_t* ctx;
  tiledb_ctx_alloc(NULL, &ctx);

  // The array will be 4x4 with dimensions "rows" and "cols", with domain [1,4].
  int dim_domain[] = {1, 4, 1, 4};
  int tile_extents[] = {2, 2};
  tiledb_dimension_t* d1;
  tiledb_dimension_alloc(
      ctx, "rows", TILEDB_INT32, &dim_domain[0], &tile_extents[0], &d1);
  tiledb_dimension_t* d2;
  tiledb_dimension_alloc(
      ctx, "cols", TILEDB_INT32, &dim_domain[2], &tile_extents[1], &d2);

  // Create domain
  tiledb_domain_t* domain;
  tiledb_domain_alloc(ctx, &domain);
  tiledb_domain_add_dimension(ctx, domain, d1);
  tiledb_domain_add_dimension(ctx, domain, d2);

  // Create a single attribute "a" so each (i,j) cell can store an integer
  tiledb_attribute_t* a;
  tiledb_attribute_alloc(ctx, "a", TILEDB_INT32, &a);

  // Create array schema
  tiledb_array_schema_t* array_schema;
  tiledb_array_schema_alloc(ctx, TILEDB_DENSE, &array_schema);
  tiledb_array_schema_set_cell_order(ctx, array_schema, TILEDB_ROW_MAJOR);
  tiledb_array_schema_set_tile_order(ctx, array_schema, TILEDB_ROW_MAJOR);
  tiledb_array_schema_set_domain(ctx, array_schema, domain);
  tiledb_array_schema_add_attribute(ctx, array_schema, a);

  // Create array
  tiledb_array_create(ctx, array_name, array_schema);

  // Clean up
  tiledb_attribute_free(&a);
  tiledb_dimension_free(&d1);
  tiledb_dimension_free(&d2);
  tiledb_domain_free(&domain);
  tiledb_array_schema_free(&array_schema);
  tiledb_ctx_free(&ctx);
}

void write_array() {
  // Create TileDB context
  tiledb_ctx_t* ctx;
  tiledb_ctx_alloc(NULL, &ctx);

  // Open array for writing
  tiledb_array_t* array;
  tiledb_array_alloc(ctx, array_name, &array);
  tiledb_array_open(ctx, array, TILEDB_WRITE);

  // Prepare some data for the array
  int coords_rows[] = {1, 2, 4, 1};
  int coords_cols[] = {2, 1, 3, 4};
  uint64_t coords_size = sizeof(coords_rows);
  int data[] = {1, 2, 3, 4};
  uint64_t data_size = sizeof(data);

  // Create the query
  tiledb_query_t* query;
  tiledb_query_alloc(ctx, array, TILEDB_WRITE, &query);
  tiledb_query_set_layout(ctx, query, TILEDB_UNORDERED);
  tiledb_query_set_data_buffer(ctx, query, "a", data, &data_size);
  tiledb_query_set_data_buffer(ctx, query, "rows", coords_rows, &coords_size);
  tiledb_query_set_data_buffer(ctx, query, "cols", coords_cols, &coords_size);

  // Submit query
  tiledb_query_submit(ctx, query);

  // Close array
  tiledb_array_close(ctx, array);

  // Clean up
  tiledb_array_free(&array);
  tiledb_query_free(&query);
  tiledb_ctx_free(&ctx);
}

void read_array() {
  // Create TileDB context
  tiledb_ctx_t* ctx;
  tiledb_ctx_alloc(NULL, &ctx);

  // Open array for reading
  tiledb_array_t* array;
  tiledb_array_alloc(ctx, array_name, &array);
  tiledb_array_open(ctx, array, TILEDB_READ);

  // Read entire array
  int subarray[] = {1, 4, 1, 4};

  // Prepare the vector that will hold the result (of size 16 elements)
  int coords_rows[16];
  int coords_cols[16];
  uint64_t coords_size = sizeof(coords_rows);
  int data[16];
  uint64_t data_size = sizeof(data);

  // Create query
  tiledb_query_t* query;
  tiledb_query_alloc(ctx, array, TILEDB_READ, &query);
  tiledb_query_set_subarray(ctx, query, subarray);
  tiledb_query_set_layout(ctx, query, TILEDB_ROW_MAJOR);
  tiledb_query_set_data_buffer(ctx, query, "a", data, &data_size);
  tiledb_query_set_data_buffer(ctx, query, "rows", coords_rows, &coords_size);
  tiledb_query_set_data_buffer(ctx, query, "cols", coords_cols, &coords_size);

  // Submit query
  tiledb_query_submit(ctx, query);

  // Close array
  tiledb_array_close(ctx, array);

  // Print out the results.
  for (int r = 0; r < 16; r++) {
    int i = coords_rows[r];
    int j = coords_cols[r];
    int a = data[r];
    printf("Cell (%d, %d) has data %d\n", i, j, a);
  }

  // Clean up
  tiledb_array_free(&array);
  tiledb_query_free(&query);
  tiledb_ctx_free(&ctx);
}

int main() {
  // Get object type
  tiledb_ctx_t* ctx;
  tiledb_ctx_alloc(NULL, &ctx);
  tiledb_object_t type;
  tiledb_object_type(ctx, array_name, &type);
  tiledb_ctx_free(&ctx);

  if (type != TILEDB_ARRAY) {
    create_array();
    write_array();
  }

  read_array();

  return 0;
}