C 代码 读取一对定义节点坐标和元素的 FEM 文件， 一维、二维或三维网格，即 节点坐标文件rar

# include <math.h> # include <stdlib.h> # include <stdio.h> # include <time.h> # include <string.h> int main ( int argc, char *argv[] ); char ch_cap ( char ch ); int ch_eqi ( char ch1, char ch2 ); int ch_to_digit ( char ch ); int file_column_count ( char *filename ); int file_row_count ( char *filename ); void gmsh_mesh1d_write ( char *gmsh_filename, int m, int node_num, double node_x[], int element_order, int element_num, int element_node[] ); void gmsh_mesh2d_write ( char *gmsh_filename, int m, int node_num, double node_x[], int element_order, int element_num, int element_node[] ); void gmsh_mesh3d_write ( char *gmsh_filename, int m, int node_num, double node_x[], int element_order, int element_num, int element_node[] ); int i4_max ( int i1, int i2 ); int i4_min ( int i1, int i2 ); int *i4mat_data_read ( char *input_filename, int m, int n ); void i4mat_header_read ( char *input_filename, int *m, int *n ); int i4mat_max ( int m, int n, int a[] ); int i4mat_min ( int m, int n, int a[] ); void i4mat_transpose_print ( int m, int n, int a[], char *title ); void i4mat_transpose_print_some ( int m, int n, int a[], int ilo, int jlo, int ihi, int jhi, char *title ); void mesh_base_one ( int node_num, int element_order, int element_num, int element_node[] ); double *r8mat_data_read ( char *input_filename, int m, int n ); void r8mat_header_read ( char *input_filename, int *m, int *n ); void r8mat_transpose_print ( int m, int n, double a[], char *title ); void r8mat_transpose_print_some ( int m, int n, double a[], int ilo, int jlo, int ihi, int jhi, char *title ); int s_len_trim ( char *s ); int s_to_i4 ( char *s, int *last, int *error ); int s_to_i4vec ( char *s, int n, int ivec[] ); double s_to_r8 ( char *s, int *lchar, int *error ); int s_to_r8vec ( char *s, int n, double rvec[] ); int s_word_count ( char *s ); void timestamp ( ); /******************************************************************************/ int main ( int argc, char *argv[] ) /******************************************************************************/ /* Purpose: MAIN is the main program for FEM_TO_GMSH. Discussion: FEM_TO_GMSH converts a 1D, 2D or 3D mesh from FEM to GMSH format. Usage: fem_to_gmsh prefix where 'prefix' is the common filename prefix: * 'prefix'_nodes.txt contains the node coordinates, * 'prefix'_elements.txt contains the element node connectivity. * 'prefix'.msh will contain the Gmsh version of the data. Licensing: This code is distributed under the GNU LGPL license. Modified: 24 June 2019 Author: John Burkardt */ { char element_filename[255]; int *element_node; int element_num; int element_order; char gmsh_filename[255]; int m; char node_filename[255]; int node_num; double *node_x; char prefix[255]; timestamp ( ); printf ( "\n" ); printf ( "FEM_TO_GMSH\n" ); printf ( " C version:\n" ); printf ( " Convert a 1D, 2D or 3D mesh to Gmsh format.\n" ); printf ( "\n" ); printf ( " Read \"prefix\"_nodes.txt, node coordinates.\n" ); printf ( " Read \"prefix\"_elements.txt, 3 or 6 node element definitions.\n" ); printf ( "\n" ); printf ( " Create \"prefix\".msh, a corresponding Gmsh mesh file.\n" ); /* Get the filename prefix. */ if ( argc <= 1 ) { printf ( "\n" ); printf ( "FEM_TO_GMSH:\n" ); printf ( " Please enter the filename prefix.\n" ); scanf ( "%s", prefix ); } else { strcpy ( prefix, argv[1] ); } /* Create the filenames. */ strcpy ( node_filename, prefix ); strcat ( node_filename, "_nodes.txt" ); strcpy ( element_filename, prefix ); strcat ( element_filename, "_elements.txt" ); strcpy ( gmsh_filename, prefix ); strcat ( gmsh_filename, ".msh" ); /* Read the node data. */ r8mat_header_read ( node_filename, &m, &node_num ); printf ( "\n" ); printf ( " Read the header of \"%s\".\n", node_filename ); printf ( "\n" ); printf ( " Spatial dimension = %d\n", m ); printf ( " Number of nodes = %d\n", node_num ); node_x = r8mat_data_read ( node_filename, m, node_num ); printf ( "\n" ); printf ( " Read the data in \"%s\".\n", node_filename ); r8mat_transpose_print_some ( m, node_num, node_x, 1, 1, m, 5, " Portion of node coordinate data:" ); /* Read the element data. */ i4mat_header_read ( element_filename, &element_order, &element_num ); if ( m == 1 ) { if ( element_order == 2 ) { } else { fprintf ( stderr, "\n" ); fprintf ( stderr, "FEM_TO_GMSH - Fatal error!\n" ); fprintf ( stderr, " 1D mesh data must use 2 nodes.\n" ); exit ( 1 ); } } else if ( m == 2 ) { if ( element_order == 3 ) { } else if ( element_order == 6 ) { } else { fprintf ( stderr, "\n" ); fprintf ( stderr, "FEM_TO_GMSH - Fatal error!\n" ); fprintf ( stderr, " 2D mesh data must use 3 or 6 nodes.\n" ); exit ( 1 ); } } else if ( m == 3 ) { if ( element_order == 4 ) { } else if ( element_order == 10 ) { } else if ( element_order == 20 ) { } else { fprintf ( stderr, "\n" ); fprintf ( stderr, "FEM_TO_GMSH - Fatal error!\n" ); fprintf ( stderr, " 3D mesh data must use 4, 10, or 20 nodes.\n" ); exit ( 1 ); } } printf ( "\n" ); printf ( " Read the header of \"%s\".\n", element_filename ); printf ( "\n" ); printf ( " Element order = %d\n", element_order ); printf ( " Number of elements = %d\n", element_num ); element_node = i4mat_data_read ( element_filename, element_order, element_num ); printf ( "\n" ); printf ( " Read the data in \"%s\".\n", element_filename ); i4mat_transpose_print_some ( element_order, element_num, element_node, 1, 1, element_order, 10, " Initial portion of element data:" ); /* Write out the Gmsh version of the data. */ if ( m == 1 ) { gmsh_mesh1d_write ( gmsh_filename, m, node_num, node_x, element_order, element_num, element_node ); } else if ( m == 2 ) { gmsh_mesh2d_write ( gmsh_filename, m, node_num, node_x, element_order, element_num, element_node ); } else if ( m == 3 ) { gmsh_mesh3d_write ( gmsh_filename, m, node_num, node_x, element_order, element_num, element_node ); } printf ( "\n" ); printf ( " Created the GMSH file \"%s\".\n", gmsh_filename ); /* Free memory. */ free ( element_node ); free ( node_x ); /* Terminate. */ printf ( "\n" ); printf ( "FEM_TO_GMSH:\n" ); printf ( " Normal end of execution.\n" ); printf ( "\n" ); timestamp ( ); return 0; } /******************************************************************************/ char ch_cap ( char ch ) /******************************************************************************/ /* Purpose: CH_CAP capitalizes a single character. Discussion: This routine should be equivalent to the library "toupper" function. Licensing: This code is distributed under the GNU LGPL license. Modified: 19 July 1998 Author: John Burkardt Parameters: Input, char CH, the character to capitalize. Output, char CH_CAP, the capitalized character. */ { if ( 97 <= ch && ch <= 122 ) { ch = ch - 32; } return ch; } /******************************************************************************/ int ch_eqi ( char ch1, char ch2 ) /******************************************************************************/ /* Purpose: CH_EQI is TRUE (1) if two characters are equal, disregarding case. Licensing: This code is distributed under the GNU LGPL license. Modified: 13 June 2003 Author: John Burkardt Parameters: Input, char CH1, CH2, the characters to compare. Output, int CH_EQI, is TRUE (1) if the two characters are equal, disregarding case and FALSE (0) otherwise. */ { int value; if ( 97 <= ch1 && ch1 <= 122 ) { ch1