PLplot  5.10.0
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros
deltaT-gen.c
Go to the documentation of this file.
1 // $Id: deltaT-gen.c 11971 2011-10-14 09:28:58Z andrewross $
2 //
3 // Copyright (C) 2009 Alan W. Irwin
4 //
5 // This file is part of PLplot.
6 // PLplot is free software; you can redistribute it and/or modify
7 // it under the terms of the GNU Library General Public License as published
8 // by the Free Software Foundation; either version 2 of the License, or
9 // (at your option) any later version.
10 //
11 // PLplot is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU Library General Public License for more details.
15 //
16 // You should have received a copy of the GNU Library General Public License
17 // along with PLplot; if not, write to the Free Software
18 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 //
20 //
21 
22 // Program for generating spline representation (xspline, yspline,
23 // and y2spline arrays) header from deltaT.dat.
24 //
25 // The program assumes that argv[1] will be the input file, and
26 // argv[2] the output file. This works cross-platform without
27 // worrying about shell redirects of stdin and stdout that are
28 // not accessible on Windows, apparently.
29 
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <math.h>
34 #include "dspline.h"
35 
36 
37 //--------------------------------------------------------------------------
38 // Function-like macro definitions
39 //--------------------------------------------------------------------------
40 
41 #define MemError1( a ) do { fprintf( stderr, "MEMORY ERROR %d\n" a "\n", __LINE__ ); exit( __LINE__ ); } while ( 0 )
42 
43 const char header[] = "" \
44  "/*\n" \
45  " This file is part of PLplot.\n" \
46  " \n" \
47  " PLplot is free software; you can redistribute it and/or modify\n" \
48  " it under the terms of the GNU Library General Public License as published\n" \
49  " by the Free Software Foundation; either version 2 of the License, or\n" \
50  " (at your option) any later version.\n" \
51  " \n" \
52  " PLplot is distributed in the hope that it will be useful,\n" \
53  " but WITHOUT ANY WARRANTY; without even the implied warranty of\n" \
54  " MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the\n" \
55  " GNU Library General Public License for more details.\n" \
56  " \n" \
57  " You should have received a copy of the GNU Library General Public License\n" \
58  " along with PLplot; if not, write to the Free Software\n" \
59  " Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA\n" \
60  " \n" \
61  " \n" \
62  " This header file contains spline data (xspline, yspline, and y2spline)\n" \
63  " for converting between UT1 and ephemeris time.\n" \
64  " It is an automatically generated file, so please do\n" \
65  " not edit it directly. Make any changes to deltaT.dat then use\n" \
66  " deltaT-gen to recreate this header file.\n" \
67  " \n" \
68  "*/";
69 
70 int main( int argc, char *argv[] )
71 {
72  FILE *fr, *fw;
73  char readbuffer[256];
74  double *xspline = NULL;
75  double *yspline = NULL;
76  double *y2spline = NULL;
77  int i = 0;
78  int number_of_lines = 0;
79 
80  if ( ( argc < 2 ) || ( fr = fopen( argv[1], "r" ) ) == NULL )
81  {
82  fprintf( stderr, "Cannot open first file as readable\n" );
83  exit( 1 );
84  }
85 
86  if ( ( argc < 3 ) || ( fw = fopen( argv[2], "w" ) ) == NULL )
87  {
88  fprintf( stderr, "Cannot open second file as writable\n" );
89  exit( 1 );
90  }
91 
92  //
93  // Work out how many lines we have all up
94  //
95 
96  while ( ( fgets( readbuffer, 255, fr ) != NULL ) )
97  {
98  ++number_of_lines;
99  }
100 
101  //
102  // Allocate memory to the arrays which will hold the data
103  //
104 
105  if ( ( xspline = (double *) calloc( (size_t) number_of_lines, (size_t) sizeof ( double ) ) ) == NULL )
106  MemError1( "Allocating memory to the xspline table" );
107 
108  if ( ( yspline = (double *) calloc( (size_t) number_of_lines, (size_t) sizeof ( double ) ) ) == NULL )
109  MemError1( "Allocating memory to the yspline table" );
110 
111  if ( ( y2spline = (double *) calloc( (size_t) number_of_lines, (size_t) sizeof ( double ) ) ) == NULL )
112  MemError1( "Allocating memory to the y2spline table" );
113 
114  rewind( fr ); // Go back to the start of the file
115 
116  //
117  // Read in line by line, and copy the numbers into our arrays
118  //
119 
120  while ( ( fgets( readbuffer, 255, fr ) != NULL ) )
121  {
122  sscanf( readbuffer, "%lf %lf", (double *) &xspline[i], (double *) &yspline[i] );
123  i++;
124  }
125 
126  fclose( fr );
127  // Calculate spline representation using second derivative condition
128  // on end points that is consistent with overall average parabolic shape
129  // of delta T curve (Morrison and Stephenson, 2004) with second
130  // derivative = 6.4e-3 secs/year/year.
131  dspline( xspline, yspline, number_of_lines, 2, 6.4e-3, 2, 6.4e-3, y2spline );
132 
133 //
134 // Write the data out to file ready to be included in our source
135 //
136 
137 
138  fprintf( fw, "%s\n", header );
139 
140  fprintf( fw, "const int number_of_entries_in_spline_tables=%d;\n\n", number_of_lines );
141 
142  fprintf( fw, "const double xspline[%d] = {\n", number_of_lines );
143  for ( i = 0; i < number_of_lines; i++ )
144  {
145  fprintf( fw, "%10.0f,\n", xspline[i] );
146  }
147  fprintf( fw, "};\n" );
148 
149  fprintf( fw, "const double yspline[%d] = {\n", number_of_lines );
150  for ( i = 0; i < number_of_lines; i++ )
151  {
152  fprintf( fw, "%10.0f,\n", yspline[i] );
153  }
154  fprintf( fw, "};\n" );
155 
156  fprintf( fw, "const double y2spline[%d] = {\n", number_of_lines );
157  for ( i = 0; i < number_of_lines; i++ )
158  {
159  fprintf( fw, "%25.15e,\n", y2spline[i] );
160  }
161  fprintf( fw, "};\n" );
162 
163  fclose( fw );
164  free( xspline );
165  free( yspline );
166  free( y2spline );
167 
168  return ( 0 );
169 }
170