sln-build.1 (6901B)
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If not, see <http://www.gnu.org/licenses/>. 18 .Dd April 17, 2026 19 .Dt SLN-BUILD 1 20 .Os 21 .\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 22 .Sh NAME 23 .Nm sln-build 24 .Nd build an acceleration structure for line importance sampling 25 .\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 26 .Sh SYNOPSIS 27 .Nm 28 .Op Fl chsv 29 .Op Fl a Ar arity 30 .Op Fl e Ar polyline_opt Ns Op : Ns Ar polyline_opt No ... 31 .Op Fl L Ar leaf_nlines 32 .Op Fl l Ar line_profile 33 .Op Fl o Ar accel_struct 34 .Fl P Ar pressure 35 .Fl T Ar temperature 36 .Fl m Ar molparams 37 .Fl x Ar mixture 38 .Op Ar lines 39 .\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 40 .Sh DESCRIPTION 41 .Nm 42 constructs a data structure designed to accelerate the sampling by 43 importance of the spectral lines defined for a gas mixture under given 44 thermodynamic conditions, from a spectroscopic parameters database. 45 The generated structure is a binary tree that stores a polyline of 46 spectral data at each node that it encompasses. 47 .Pp 48 The input spectroscopic data, i.e., the line list and isotopological 49 metadata, are formatted in HITRAN file formats. 50 If not provided, the list of lines is read from standard input. 51 .Pp 52 The options are as follows: 53 .Bl -tag -width Ds 54 .\"""""""""""""""""""""""""""""""""" 55 .It Fl a Ar arity 56 Maximum number of children of an internal node in the constructed tree 57 that partitions the input lines. 58 It cannot be less than 2, which is its default value. 59 .\"""""""""""""""""""""""""""""""""" 60 .It Fl c 61 For each internal node, construct its polyline by merging the polylines 62 of its children in pairs and then simplifying the result of this merge. 63 The process is repeated on the resulting polylines until only a single 64 polyline remains, which becomes the polyline of the internal node. 65 In other words, these polylines are constructed by successively 66 collapsing the polylines of the child nodes. 67 .Pp 68 By default, the polylines of the internal nodes are constructed in a 69 single step of merging and simplification that takes into account all 70 child polylines at once. 71 .\"""""""""""""""""""""""""""""""""" 72 .It Fl e Ar polyline_opt Ns Op : Ns Ar polyline_opt No ... 73 Configure the polylines, i.e., the data used to encode the shape of the 74 spectrum in the acceleration structure. 75 .Pp 76 The polyline options are as follows: 77 .Bl -tag -width Ds 78 .It Cm err= Ns Ar decimation_error 79 Relative error used to simplifly polylines. 80 The larger it is, the coarser the polylines obtained, and therefore the 81 less memory it uses. 82 The default value is 0.01. 83 .It Cm mesh= Ns Ar mesh_type 84 Define how the polylines are meshed. 85 .Pp 86 The supported 87 .Ar mesh_type 88 values are as follows: 89 .Bl -tag -width Ds 90 .It Cm fit 91 The polylines fit the spectrum data. 92 .It Cm upper 93 The polylines define an upper limit for the spectrum they encode. 94 This is the default behavior. 95 .El 96 .It Cm vcount= Ns Ar vertex_count_hint 97 Recommendation for the number of vertices around the center of the line. 98 The fewer vertices there are, the coarser the polyline of a line and the 99 smaller the memory usage. 100 The default value is 16. 101 .El 102 .\"""""""""""""""""""""""""""""""""" 103 .It Fl h 104 Display short help and exit. 105 .\"""""""""""""""""""""""""""""""""" 106 .It Fl L Ar leaf_nlines 107 Maximum number of lines per tree leaf. 108 The default value is 1. 109 .\"""""""""""""""""""""""""""""""""" 110 .It Fl l Ar line_profile 111 Defines the line profile. 112 Currently, 113 .Cm voigt 114 is the only supported profile and therefore the default value. 115 .\"""""""""""""""""""""""""""""""""" 116 .It Fl o Ar accel_struct 117 Output file. 118 If not defined, the acceleration structure is written to standard output. 119 .\"""""""""""""""""""""""""""""""""" 120 .It Fl P Ar pressure 121 Pressure of the gaz mixture, in atmospheres 122 .Pq 1 atm = 1.01315 bar . 123 .\"""""""""""""""""""""""""""""""""" 124 .It Fl s 125 Specifies that input lines are formatted according to the binary format 126 as written by the 127 .Xr shtr 1 128 utility, and not according to the HITRAN format. 129 This format is more compact, allowing for faster loading of line data. 130 .\"""""""""""""""""""""""""""""""""" 131 .It Fl T Ar temperature 132 Temperature of the gaz mixture, in Kelvin. 133 .\"""""""""""""""""""""""""""""""""" 134 .It Fl m Ar molparams 135 Isotopologue metadata in HITRAN format. 136 .\"""""""""""""""""""""""""""""""""" 137 .It Fl v 138 Make 139 .Nm 140 verbose. 141 Multiple 142 .Fl v 143 options increase the verbosity. 144 The maximum is 3. 145 .\"""""""""""""""""""""""""""""""""" 146 .It Fl x Ar mixture 147 Composition of the gaz mixture in 148 .Xr sln-mixture 5 149 format. 150 If a molecule is absent from this file, its concentration in the mixture 151 is assumed to be zero. 152 .El 153 .\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 154 .Sh EXIT STATUS 155 .Ex -std 156 .\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 157 .Sh EXAMPLES 158 Build a structure that accelerates importance sampling of the lines in 159 the H2O spectrum, between 0 and 50 cm^-1, at a pressure of 1 atm and a 160 temperature of 292 K. 161 Use the default options to mesh the spectrum, so that the resulting 162 structure represents an upper bound on the spectral data: 163 .Bd -literal -offset Ds 164 sln-build -P 1 -T 292 -o H2O_0-50_HITEMP2010_tree.bin \e 165 -m /path/to/hitran/molparams.txt -x mixture.txt \e 166 /path/to/hitran//H2O/01_0-50_HITEMP2010.par 167 .Ed 168 .\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 169 .Sh SEE ALSO 170 .Xr shtr 1 , 171 .Xr sln-mixture 5 172 .Rs 173 .%A Yaniss Nyffenegger-Péré et al. 174 .%T Spectrally refined unbiased monte carlo estimate of the earth's \ 175 global radiative cooling 176 .%J Proceedings of the National Academy of Sciences 177 .%P e2315492121 178 .%V 121 179 .%N 5 180 .%D 2024 181 .Re 182 .Rs 183 .%T The HITRAN Database 184 .%U https://hitran.org/ 185 .Re 186 .\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 187 .Sh STANDARDS 188 .Rs 189 .%A L.S. Rothman et al. 190 .%T The HITRAN2012 molecular spectroscopic database 191 .%J Journal of Quantitative Spectroscopy & Radiative Transfer 192 .%V 130 193 .%P pp. 4\(en50 194 .%D 2013 195 .Re 196 .Pp 197 .Rs 198 .%A L.S. Rothman et al. 199 .%T HITEMP, the high-temperature molecular spectroscopic database 200 .%J Journal of Quantitative Spectroscopu & Radiative Transfer 201 .%V 111 202 .%P pp. 2139\(en2150 203 .%D 2010 204 .Re