Reading calculation grid

Reads a calculation grid from the CGNS file. iRIClib offers subroutines for reading structured grids only.

Table 62 Subroutine to use

Subroutine

Remarks

cg_iric_gotogridcoord2d_f

Makes preparations for reading a 2D structured grid

cg_iric_getgridcoord2d_f

Reads a 2D structured grid

cg_iric_gotogridcoord3d_f

Makes preparations for reading a 3D structured grid

cg_iric_getgridcoord3d_f

Reads a 3D structured grid

cg_iric_read_grid_integer_node_f

Reads the integer attribute values defined for grid nodes

cg_iric_read_grid_real_node_f

Reads the double-precision attribute values defined for grid nodes

cg_iric_read_grid_integer_cell_f

Reads the integer attribute values defined for cells

cg_iric_read_grid_real_cell_f

Reads the double-precision attribute values defined for cells

cg_iric_read_complex_count_f

Reads the number of groups of complex type grid attribute

cg_iric_read_complex_integer_f

Reads the integer attribute values of complex type grid attribute

cg_iric_read_complex_real_f

Reads the double precision attribute values of complex type grid attribute

cg_iric_read_complex_realsingle_f

Reads the single precision attribute values of complex type grid attribute

cg_iric_read_complex_string_f

Reads the string attribute values of complex type grid attribute

cg_iric_read_complex_functionalsize_f

Checks the size of a functional-type attribute of complex type grid attribute

cg_iric_read_complex_functional_f

Reads functional attribute data of complex type grid attribute

cg_iric_read_complex_functionalwithname_f

Reads functional attribute of complex type grid attribute (with multiple values)

cg_iric_read_complex_functional_realsingle_f

Reads functional attribute data of complex type grid attribute

cg_iric_read_grid_complex_node_f

Reads the complex attribute values defined at grid nodes

cg_iric_read_grid_complex_cell_f

Reads the complex attribute values defined at grid cells

cg_iric_read_grid_functionaltimesize_f

Reads the number of values of dimension "Time" for functional grid attribute

cg_iric_read_grid_functionaltime_f

Reads the values of dimension "Time" for functional grid attribute

cg_iric_read_grid_functionaldimensionsize_f

Reads the number of values of dimension for functional grid attribute

cg_iric_read_grid_functionaldimension_integer_f

Reads the values of integer dimension for functional grid attribute

cg_iric_read_grid_functionaldimension_real_f

Reads the values of double-precision dimension for functional grid attribute

cg_iric_read_grid_functional_integer_node_f

Reads the values of functional integer grid attribute with dimension "Time" definied at grid nodes.

cg_iric_read_grid_functional_real_node_f

Reads the values of functional double-precision grid attribute with dimension "Time" definied at grid nodes.

cg_iric_read_grid_functional_integer_cell_f

Reads the values of functional integer grid attribute with dimension "Time" definied at grid cells.

cg_iric_read_grid_functional_real_cell_f

Reads the values of functional double-precision grid attribute with dimension "Time" definied at grid cells.

The same subroutines for getting attributes such as cg_iric_read_grid_integer_node_f can be used both for two-dimensional structured grids and three-dimensional structured grids.

An example description for reading a two-dimensional structured grid is shown in List 95.

List 95 Example of source code to read a grid
 1program Sample3
 2  implicit none
 3  include 'cgnslib_f.h'
 4
 5  integer:: fin, ier, discharge_size, i, j
 6  integer:: isize, jsize
 7  double precision, dimension(:,:), allocatable:: grid_x, grid_y
 8  double precision, dimension(:,:), allocatable:: elevation
 9  integer, dimension(:,:), allocatable:: obstacle
10  integer:: rain_timeid
11  integer:: rain_timesize
12  double precision, dimension(:), allocatable:: rain_time
13  double precision, dimension(:,:), allocatable:: rain
14
15  ! Open CGNS file
16  call cg_open_f('test.cgn', CG_MODE_MODIFY, fin, ier)
17  if (ier /=0) STOP "*** Open error of CGNS file ***"
18
19  ! Initialize iRIClib
20  call cg_iric_init_f(fin, ier)
21  if (ier /=0) STOP "*** Initialize error of CGNS file ***"
22
23  ! Check the grid size
24  call cg_iric_gotogridcoord2d_f(isize, jsize, ier)
25
26  ! Allocate memory for loading the grid
27  allocate(grid_x(isize,jsize), grid_y(isize,jsize))
28  ! Read the grid into memory
29  call cg_iric_getgridcoord2d_f(grid_x, grid_y, ier)
30
31  if (ier /=0) STOP "*** No grid data ***"
32  ! (Output)
33  print *, 'grid x,y: isize, jsize=', isize, jsize
34  do i = 1, min(isize,5)
35    do j = 1, min(jsize,5)
36      print *, ' (',i,',',j,')=(',grid_x(i,j),',',grid_y(i,j),')'
37    end do
38  end do
39
40  ! Allocate memory for elevation attribute values that are defined for grid nodes.
41  allocate(elevation(isize, jsize))
42  ! Read the attribute values.
43  call cg_iric_read_grid_real_node_f('Elevation', elevation, ier)
44  print *, 'Elevation: isize, jsize=', isize, jsize
45  do i = 1, min(isize,5)
46    do j = 1, min(jsize,5)
47      print *, ' (',i,',',j,')=(',elevation(i,j),')'
48    end do
49  end do
50
51  ! Allocate memory for the obstacle attribute that is defined for cells. The size is (isize-1) * (jsize-1) since it is cell attribute.
52  allocate(obstacle(isize-1, jsize-1))
53  ! Read the attribute values in.
54  call cg_iric_read_grid_integer_cell_f('Obstacle', obstacle, ier)
55  print *, 'Obstacle: isize -1, jsize-1=', isize-1, jsize-1
56  do i = 1, min(isize-1,5)
57    do j = 1, min(jsize-1,5)
58      print *, ' (',i,',',j,')=(',obstacle(i,j),')'
59    end do
60  end do
61  ! Read the number of times for Rain
62  call cg_iric_read_grid_functionaltimesize_f('Rain', rain_timesize);
63  ! Allocate memory for time values of Rain
64  allocate(rain_time(rain_timesize))
65
66  ! Allocate memory for the rain attribute that is defined for cells. The size is (isize-1) * (jsize-1) since it is cell attribute.  allocate(rain(isize-1, jsize-1))
67  ! Read the attribute at Time = 1
68  rain_timeid = 1
69  call cg_iric_read_grid_functional_real_cell_f('Rain', rain_timeid, rain, ier)
70  print *, 'Rain: isize -1, jsize-1=', isize-1, jsize-1
71  do i = 1, min(isize-1,5)
72    do j = 1, min(jsize-1,5)
73      print *, ' (',i,',',j,')=(',rain(i,j),')'
74    end do
75  end do
76
77  ! Deallocate memory that has been allocated
78  deallocate(grid_x, grid_y, elevation, obstacle, rain_time, rain)
79
80  ! Close CGNS file
81  call cg_close_f(fin, ier)
82  stop
83end program Sample3

Processing for a three-dimensional grid can be described in the same manner.