1 | function nc_cat_a ( input_ncfiles, output_ncfile, abscissa_var ) |
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2 | % NC_CAT_A: concatentates a set of netcdf files into ascending order |
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3 | % |
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4 | % The concatenation is done only along unlimited variable, which by |
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5 | % definition have an unlimited dimension. Variables which do NOT have |
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6 | % an unlimited dimension are copied over from the first of the input |
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7 | % netcdf input files. |
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8 | % |
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9 | % This m-file is not meant as a replacement for ncrcat or any of Charles |
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10 | % Zender's terrific NCO tools. If you need NCO functionality, you should |
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11 | % get NCO tools from http://nco.sourceforge.net |
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12 | % |
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13 | % USAGE: nc_cat_a ( input_ncfiles, output_ncfile, abscissa_var ) |
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14 | % |
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15 | % PARAMETERS: |
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16 | % Input: |
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17 | % input_ncfiles: |
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18 | % This can be either a cell array of netcdf files, or a text |
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19 | % file with one netcdf file per line |
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20 | % output_ncfile: |
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21 | % This file will be generated from scratch. |
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22 | % abscissa_var: |
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23 | % Name of an unlimited variable. Supposing we are dealing |
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24 | % with time series, then a good candidate for this would |
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25 | % be a variable called, oh, I don't know, maybe "time". |
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26 | % Output: |
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27 | % None. An exception is thrown in case of an error. |
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28 | % |
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29 | % The best way to explain this is with simple examples. Suppose that |
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30 | % the abscissa_var is "time" and that the other netcdf variable is "tsq". |
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31 | % Suppose that the first netcdf file has files for "time" and "tsq" of |
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32 | % |
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33 | % time: 0 2 4 |
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34 | % tsq: 0 4 16 |
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35 | % |
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36 | % Suppose the 2nd netcdf file has values of |
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37 | % |
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38 | % time: 4 6 8 |
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39 | % tsq: 18 36 64 |
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40 | % |
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41 | % Note that the 2nd time series has a different value of "tsq" for the |
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42 | % abscissa value of 4. |
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43 | % |
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44 | % Running nc_cat_asc will produce a single time series of |
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45 | % |
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46 | % time: 0 2 4 6 8 |
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47 | % tsq: 0 4 18 36 64 |
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48 | % |
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49 | % In other words, the 2nd netcdf file's abscissa/ordinate values take |
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50 | % precedence. So the order of your netcdf files matter, and the output |
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51 | % netcdf file will have unique abscissa values. |
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52 | |
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53 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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54 | % |
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55 | % $Id:$ |
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56 | % $LastChangedDate:$ |
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57 | % $LastChangedRevision:$ |
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58 | % $LastChangedBy:$ |
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59 | % |
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60 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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61 | |
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62 | |
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63 | |
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64 | error(nargchk(3,3,nargin,'struct')); |
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65 | error(nargoutchk(0,0,nargout,'struct')); |
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66 | |
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67 | |
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68 | % |
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69 | % If the first input is of type char and is a file, then read it in. |
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70 | % At the end of this process, the list of netcdf files to be |
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71 | % concatenated is in a cell array. |
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72 | if ischar(input_ncfiles) && exist(input_ncfiles,'file') |
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73 | |
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74 | afid = fopen ( input_ncfiles, 'r' ); |
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75 | x = textscan ( afid, '%s' ); |
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76 | input_ncfiles = x{1}; |
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77 | |
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78 | elseif iscell ( input_ncfiles ) |
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79 | |
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80 | % |
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81 | % Do nothing |
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82 | |
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83 | else |
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84 | error ( 'first input must be either a text file or a cell array\n' ); |
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85 | end |
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86 | |
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87 | num_input_files = length(input_ncfiles); |
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88 | |
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89 | |
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90 | % |
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91 | % This is how close the abscissa variable values have to be before they |
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92 | % are considered to be the same value. |
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93 | tol = 10*eps; |
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94 | |
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95 | |
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96 | % |
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97 | % Now construct the empty output netcdf file. |
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98 | ncm = nc_info ( input_ncfiles{1} ); |
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99 | mode = nc_clobber_mode; |
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100 | |
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101 | nc_create_empty(output_ncfile,mode); |
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102 | |
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103 | |
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104 | % |
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105 | % Add the dimensions. |
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106 | for d = 1:length(ncm.Dimension) |
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107 | if ncm.Dimension(d).Unlimited |
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108 | nc_add_dimension ( output_ncfile, ncm.Dimension(d).Name, 0 ); |
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109 | else |
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110 | nc_add_dimension ( output_ncfile, ncm.Dimension(d).Name, ncm.Dimension(d).Length ); |
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111 | end |
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112 | end |
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113 | |
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114 | % |
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115 | % Add the variables |
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116 | for v = 1:length(ncm.Dataset) |
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117 | nc_addvar ( output_ncfile, ncm.Dataset(v) ); |
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118 | |
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119 | % |
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120 | % If the variable is NOT unlimited, then we can copy over |
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121 | % its data now |
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122 | if ~ncm.Dataset(v).Unlimited |
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123 | vardata = nc_varget ( input_ncfiles{1}, ncm.Dataset(v).Name ); |
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124 | nc_varput ( output_ncfile, ncm.Dataset(v).Name, vardata ); |
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125 | end |
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126 | end |
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127 | |
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128 | |
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129 | % |
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130 | % Go thru and figure out how much data we are looking at, |
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131 | % then pre-allocate for speed. |
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132 | total_length = 0; |
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133 | for j = 1:num_input_files |
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134 | sz = nc_varsize ( input_ncfiles{j}, abscissa_var ); |
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135 | total_length = total_length + sz; |
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136 | end |
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137 | |
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138 | abscissa_vardata = NaN*ones(total_length,1); |
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139 | file_index = NaN*ones(total_length,1); |
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140 | infile_abscissa_varindex = NaN*ones(total_length,1); |
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141 | |
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142 | |
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143 | |
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144 | % |
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145 | % Now read in the abscissa variable for each file. |
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146 | start_index = 1; |
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147 | for j = 1:num_input_files |
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148 | v = nc_varget ( input_ncfiles{j}, abscissa_var ); |
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149 | nv = length(v); |
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150 | |
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151 | end_index = start_index + nv - 1; |
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152 | inds = start_index:end_index; |
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153 | |
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154 | abscissa_vardata(inds) = v; |
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155 | file_index(inds) = j*ones(nv,1); |
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156 | infile_abscissa_varindex(inds) = (0:nv-1)'; |
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157 | |
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158 | start_index = start_index + nv; |
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159 | end |
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160 | |
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161 | |
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162 | % |
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163 | % Sort the ascissa_vardata into ascending order. |
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164 | [abscissa_vardata,I] = sort ( abscissa_vardata ); |
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165 | file_index = file_index(I); |
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166 | infile_abscissa_varindex = infile_abscissa_varindex(I); |
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167 | |
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168 | % |
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169 | % Are there any duplicates? |
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170 | ind = find ( diff(abscissa_vardata) < tol ); |
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171 | if ~isempty(ind) |
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172 | abscissa_vardata(ind) = []; |
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173 | file_index(ind) = []; |
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174 | infile_abscissa_varindex(ind) = []; |
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175 | end |
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176 | |
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177 | |
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178 | % |
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179 | % So now go thru each record and append it to the output file and we |
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180 | % are done. |
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181 | for j = 1:length(abscissa_vardata) |
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182 | ncfile = input_ncfiles{file_index(j)}; |
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183 | start = infile_abscissa_varindex(j); |
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184 | input_record = nc_getbuffer ( ncfile, start, 1 ); |
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185 | nc_addnewrecs ( output_ncfile, input_record, abscissa_var ); |
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186 | end |
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187 | |
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