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| 50 | <h1>Source code for sas.data_util.nxsunit</h1><div class="highlight"><pre> |
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| 51 | <span class="c"># This program is public domain</span> |
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| 52 | <span class="c"># Author: Paul Kienzle</span> |
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| 53 | <span class="sd">"""</span> |
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| 54 | <span class="sd">Define unit conversion support for NeXus style units.</span> |
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| 55 | |
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| 56 | <span class="sd">The unit format is somewhat complicated. There are variant spellings</span> |
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| 57 | <span class="sd">and incorrect capitalization to worry about, as well as forms such as</span> |
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| 58 | <span class="sd">"mili*metre" and "1e-7 seconds".</span> |
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| 59 | |
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| 60 | <span class="sd">This is a minimal implementation of units including only what I happen to</span> |
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| 61 | <span class="sd">need now. It does not support the complete dimensional analysis provided</span> |
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| 62 | <span class="sd">by the package udunits on which NeXus is based, or even the units used</span> |
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| 63 | <span class="sd">in the NeXus definition files.</span> |
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| 64 | |
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| 65 | <span class="sd">Unlike other units packages, this package does not carry the units along with </span> |
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| 66 | <span class="sd">the value but merely provides a conversion function for transforming values.</span> |
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| 67 | |
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| 68 | <span class="sd">Usage example::</span> |
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| 69 | |
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| 70 | <span class="sd"> import nxsunit</span> |
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| 71 | <span class="sd"> u = nxsunit.Converter('mili*metre') # Units stored in mm</span> |
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| 72 | <span class="sd"> v = u(3000,'m') # Convert the value 3000 mm into meters</span> |
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| 73 | |
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| 74 | <span class="sd">NeXus example::</span> |
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| 75 | |
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| 76 | <span class="sd"> # Load sample orientation in radians regardless of how it is stored.</span> |
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| 77 | <span class="sd"> # 1. Open the path</span> |
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| 78 | <span class="sd"> file.openpath('/entry1/sample/sample_orientation')</span> |
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| 79 | <span class="sd"> # 2. scan the attributes, retrieving 'units'</span> |
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| 80 | <span class="sd"> units = [for attr,value in file.attrs() if attr == 'units']</span> |
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| 81 | <span class="sd"> # 3. set up the converter (assumes that units actually exists)</span> |
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| 82 | <span class="sd"> u = nxsunit.Converter(units[0])</span> |
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| 83 | <span class="sd"> # 4. read the data and convert to the correct units</span> |
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| 84 | <span class="sd"> v = u(file.read(),'radians')</span> |
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| 85 | |
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| 86 | <span class="sd">This is a standalone module, not relying on either DANSE or NeXus, and</span> |
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| 87 | <span class="sd">can be used for other unit conversion tasks.</span> |
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| 88 | |
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| 89 | <span class="sd">Note: minutes are used for angle and seconds are used for time. We</span> |
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| 90 | <span class="sd">cannot tell what the correct interpretation is without knowing something</span> |
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| 91 | <span class="sd">about the fields themselves. If this becomes an issue, we will need to</span> |
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| 92 | <span class="sd">allow the application to set the dimension for the unit rather than</span> |
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| 93 | <span class="sd">inferring the dimension from an example unit.</span> |
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| 94 | <span class="sd">"""</span> |
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| 95 | |
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| 96 | <span class="c"># TODO: Add udunits to NAPI rather than reimplementing it in python</span> |
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| 97 | <span class="c"># TODO: Alternatively, parse the udunits database directly</span> |
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| 98 | <span class="c"># UDUnits:</span> |
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| 99 | <span class="c"># http://www.unidata.ucar.edu/software/udunits/udunits-1/udunits.txt</span> |
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| 100 | |
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| 101 | <span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">division</span> |
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| 102 | <span class="kn">import</span> <span class="nn">math</span> |
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| 103 | |
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| 104 | <span class="n">__all__</span> <span class="o">=</span> <span class="p">[</span><span class="s">'Converter'</span><span class="p">]</span> |
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| 105 | |
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| 106 | <span class="c"># Limited form of units for returning objects of a specific type.</span> |
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| 107 | <span class="c"># Maybe want to do full units handling with e.g., pyre's</span> |
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| 108 | <span class="c"># unit class. For now lets keep it simple. Note that</span> |
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| 109 | <span class="k">def</span> <span class="nf">_build_metric_units</span><span class="p">(</span><span class="n">unit</span><span class="p">,</span><span class="n">abbr</span><span class="p">):</span> |
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| 110 | <span class="sd">"""</span> |
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| 111 | <span class="sd"> Construct standard SI names for the given unit.</span> |
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| 112 | <span class="sd"> Builds e.g.,</span> |
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| 113 | <span class="sd"> s, ns</span> |
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| 114 | <span class="sd"> second, nanosecond, nano*second</span> |
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| 115 | <span class="sd"> seconds, nanoseconds</span> |
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| 116 | <span class="sd"> Includes prefixes for femto through peta.</span> |
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| 117 | |
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| 118 | <span class="sd"> Ack! Allows, e.g., Coulomb and coulomb even though Coulomb is not</span> |
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| 119 | <span class="sd"> a unit because some NeXus files store it that way!</span> |
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| 120 | <span class="sd"> </span> |
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| 121 | <span class="sd"> Returns a dictionary of names and scales.</span> |
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| 122 | <span class="sd"> """</span> |
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| 123 | <span class="n">prefix</span> <span class="o">=</span> <span class="nb">dict</span><span class="p">(</span><span class="n">peta</span><span class="o">=</span><span class="mf">1e15</span><span class="p">,</span><span class="n">tera</span><span class="o">=</span><span class="mf">1e12</span><span class="p">,</span><span class="n">giga</span><span class="o">=</span><span class="mf">1e9</span><span class="p">,</span><span class="n">mega</span><span class="o">=</span><span class="mf">1e6</span><span class="p">,</span><span class="n">kilo</span><span class="o">=</span><span class="mf">1e3</span><span class="p">,</span> |
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| 124 | <span class="n">deci</span><span class="o">=</span><span class="mf">1e-1</span><span class="p">,</span><span class="n">centi</span><span class="o">=</span><span class="mf">1e-2</span><span class="p">,</span><span class="n">milli</span><span class="o">=</span><span class="mf">1e-3</span><span class="p">,</span><span class="n">mili</span><span class="o">=</span><span class="mf">1e-3</span><span class="p">,</span><span class="n">micro</span><span class="o">=</span><span class="mf">1e-6</span><span class="p">,</span> |
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| 125 | <span class="n">nano</span><span class="o">=</span><span class="mf">1e-9</span><span class="p">,</span><span class="n">pico</span><span class="o">=</span><span class="mf">1e-12</span><span class="p">,</span><span class="n">femto</span><span class="o">=</span><span class="mf">1e-15</span><span class="p">)</span> |
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| 126 | <span class="n">short_prefix</span> <span class="o">=</span> <span class="nb">dict</span><span class="p">(</span><span class="n">P</span><span class="o">=</span><span class="mf">1e15</span><span class="p">,</span><span class="n">T</span><span class="o">=</span><span class="mf">1e12</span><span class="p">,</span><span class="n">G</span><span class="o">=</span><span class="mf">1e9</span><span class="p">,</span><span class="n">M</span><span class="o">=</span><span class="mf">1e6</span><span class="p">,</span><span class="n">k</span><span class="o">=</span><span class="mf">1e3</span><span class="p">,</span> |
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| 127 | <span class="n">d</span><span class="o">=</span><span class="mf">1e-1</span><span class="p">,</span><span class="n">c</span><span class="o">=</span><span class="mf">1e-2</span><span class="p">,</span><span class="n">m</span><span class="o">=</span><span class="mf">1e-3</span><span class="p">,</span><span class="n">u</span><span class="o">=</span><span class="mf">1e-6</span><span class="p">,</span> |
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| 128 | <span class="n">n</span><span class="o">=</span><span class="mf">1e-9</span><span class="p">,</span><span class="n">p</span><span class="o">=</span><span class="mf">1e-12</span><span class="p">,</span><span class="n">f</span><span class="o">=</span><span class="mf">1e-15</span><span class="p">)</span> |
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| 129 | <span class="nb">map</span> <span class="o">=</span> <span class="p">{</span><span class="n">abbr</span><span class="p">:</span><span class="mi">1</span><span class="p">}</span> |
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| 130 | <span class="nb">map</span><span class="o">.</span><span class="n">update</span><span class="p">([(</span><span class="n">P</span><span class="o">+</span><span class="n">abbr</span><span class="p">,</span><span class="n">scale</span><span class="p">)</span> <span class="k">for</span> <span class="p">(</span><span class="n">P</span><span class="p">,</span><span class="n">scale</span><span class="p">)</span> <span class="ow">in</span> <span class="n">short_prefix</span><span class="o">.</span><span class="n">iteritems</span><span class="p">()])</span> |
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| 131 | <span class="k">for</span> <span class="n">name</span> <span class="ow">in</span> <span class="p">[</span><span class="n">unit</span><span class="p">,</span><span class="n">unit</span><span class="o">.</span><span class="n">capitalize</span><span class="p">()]:</span> |
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| 132 | <span class="nb">map</span><span class="o">.</span><span class="n">update</span><span class="p">({</span><span class="n">name</span><span class="p">:</span><span class="mi">1</span><span class="p">,</span><span class="n">name</span><span class="o">+</span><span class="s">'s'</span><span class="p">:</span><span class="mi">1</span><span class="p">})</span> |
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| 133 | <span class="nb">map</span><span class="o">.</span><span class="n">update</span><span class="p">([(</span><span class="n">P</span><span class="o">+</span><span class="n">name</span><span class="p">,</span><span class="n">scale</span><span class="p">)</span> <span class="k">for</span> <span class="p">(</span><span class="n">P</span><span class="p">,</span><span class="n">scale</span><span class="p">)</span> <span class="ow">in</span> <span class="n">prefix</span><span class="o">.</span><span class="n">iteritems</span><span class="p">()])</span> |
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| 134 | <span class="nb">map</span><span class="o">.</span><span class="n">update</span><span class="p">([(</span><span class="n">P</span><span class="o">+</span><span class="s">'*'</span><span class="o">+</span><span class="n">name</span><span class="p">,</span><span class="n">scale</span><span class="p">)</span> <span class="k">for</span> <span class="p">(</span><span class="n">P</span><span class="p">,</span><span class="n">scale</span><span class="p">)</span> <span class="ow">in</span> <span class="n">prefix</span><span class="o">.</span><span class="n">iteritems</span><span class="p">()])</span> |
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| 135 | <span class="nb">map</span><span class="o">.</span><span class="n">update</span><span class="p">([(</span><span class="n">P</span><span class="o">+</span><span class="n">name</span><span class="o">+</span><span class="s">'s'</span><span class="p">,</span><span class="n">scale</span><span class="p">)</span> <span class="k">for</span> <span class="p">(</span><span class="n">P</span><span class="p">,</span><span class="n">scale</span><span class="p">)</span> <span class="ow">in</span> <span class="n">prefix</span><span class="o">.</span><span class="n">iteritems</span><span class="p">()])</span> |
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| 136 | <span class="k">return</span> <span class="nb">map</span> |
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| 137 | |
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| 138 | <span class="k">def</span> <span class="nf">_build_plural_units</span><span class="p">(</span><span class="o">**</span><span class="n">kw</span><span class="p">):</span> |
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| 139 | <span class="sd">"""</span> |
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| 140 | <span class="sd"> Construct names for the given units. Builds singular and plural form.</span> |
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| 141 | <span class="sd"> """</span> |
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| 142 | <span class="nb">map</span> <span class="o">=</span> <span class="p">{}</span> |
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| 143 | <span class="nb">map</span><span class="o">.</span><span class="n">update</span><span class="p">([(</span><span class="n">name</span><span class="p">,</span><span class="n">scale</span><span class="p">)</span> <span class="k">for</span> <span class="n">name</span><span class="p">,</span><span class="n">scale</span> <span class="ow">in</span> <span class="n">kw</span><span class="o">.</span><span class="n">iteritems</span><span class="p">()])</span> |
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| 144 | <span class="nb">map</span><span class="o">.</span><span class="n">update</span><span class="p">([(</span><span class="n">name</span><span class="o">+</span><span class="s">'s'</span><span class="p">,</span><span class="n">scale</span><span class="p">)</span> <span class="k">for</span> <span class="n">name</span><span class="p">,</span><span class="n">scale</span> <span class="ow">in</span> <span class="n">kw</span><span class="o">.</span><span class="n">iteritems</span><span class="p">()])</span> |
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| 145 | <span class="k">return</span> <span class="nb">map</span> |
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| 146 | |
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| 147 | <span class="k">def</span> <span class="nf">_caret_optional</span><span class="p">(</span><span class="n">s</span><span class="p">):</span> |
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| 148 | <span class="sd">"""</span> |
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| 149 | <span class="sd"> Strip '^' from unit names.</span> |
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| 150 | |
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| 151 | <span class="sd"> * WARNING * this will incorrect transform 10^3 to 103.</span> |
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| 152 | <span class="sd"> """</span> |
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| 153 | <span class="n">s</span><span class="o">.</span><span class="n">update</span><span class="p">((</span><span class="n">k</span><span class="o">.</span><span class="n">replace</span><span class="p">(</span><span class="s">'^'</span><span class="p">,</span><span class="s">''</span><span class="p">),</span><span class="n">v</span><span class="p">)</span> |
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| 154 | <span class="k">for</span> <span class="n">k</span><span class="p">,</span><span class="n">v</span> <span class="ow">in</span> <span class="n">s</span><span class="o">.</span><span class="n">items</span><span class="p">()</span> |
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| 155 | <span class="k">if</span> <span class="s">'^'</span> <span class="ow">in</span> <span class="n">k</span><span class="p">)</span> |
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| 156 | |
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| 157 | <span class="k">def</span> <span class="nf">_build_all_units</span><span class="p">():</span> |
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| 158 | <span class="n">distance</span> <span class="o">=</span> <span class="n">_build_metric_units</span><span class="p">(</span><span class="s">'meter'</span><span class="p">,</span><span class="s">'m'</span><span class="p">)</span> |
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| 159 | <span class="n">distance</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">_build_metric_units</span><span class="p">(</span><span class="s">'metre'</span><span class="p">,</span><span class="s">'m'</span><span class="p">))</span> |
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| 160 | <span class="n">distance</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">_build_plural_units</span><span class="p">(</span><span class="n">micron</span><span class="o">=</span><span class="mf">1e-6</span><span class="p">,</span> <span class="n">Angstrom</span><span class="o">=</span><span class="mf">1e-10</span><span class="p">))</span> |
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| 161 | <span class="n">distance</span><span class="o">.</span><span class="n">update</span><span class="p">({</span><span class="s">'A'</span><span class="p">:</span><span class="mf">1e-10</span><span class="p">,</span> <span class="s">'Ang'</span><span class="p">:</span><span class="mf">1e-10</span><span class="p">})</span> |
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| 162 | |
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| 163 | <span class="c"># Note: minutes are used for angle</span> |
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| 164 | <span class="n">time</span> <span class="o">=</span> <span class="n">_build_metric_units</span><span class="p">(</span><span class="s">'second'</span><span class="p">,</span><span class="s">'s'</span><span class="p">)</span> |
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| 165 | <span class="n">time</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">_build_plural_units</span><span class="p">(</span><span class="n">hour</span><span class="o">=</span><span class="mi">3600</span><span class="p">,</span><span class="n">day</span><span class="o">=</span><span class="mi">24</span><span class="o">*</span><span class="mi">3600</span><span class="p">,</span><span class="n">week</span><span class="o">=</span><span class="mi">7</span><span class="o">*</span><span class="mi">24</span><span class="o">*</span><span class="mi">3600</span><span class="p">))</span> |
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| 166 | |
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| 167 | <span class="c"># Note: seconds are used for time</span> |
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| 168 | <span class="n">angle</span> <span class="o">=</span> <span class="n">_build_plural_units</span><span class="p">(</span><span class="n">degree</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">minute</span><span class="o">=</span><span class="mi">1</span><span class="o">/</span><span class="mf">60.</span><span class="p">,</span> |
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| 169 | <span class="n">arcminute</span><span class="o">=</span><span class="mi">1</span><span class="o">/</span><span class="mf">60.</span><span class="p">,</span> <span class="n">arcsecond</span><span class="o">=</span><span class="mi">1</span><span class="o">/</span><span class="mf">3600.</span><span class="p">,</span> <span class="n">radian</span><span class="o">=</span><span class="mi">180</span><span class="o">/</span><span class="n">math</span><span class="o">.</span><span class="n">pi</span><span class="p">)</span> |
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| 170 | <span class="n">angle</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">deg</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">arcmin</span><span class="o">=</span><span class="mi">1</span><span class="o">/</span><span class="mf">60.</span><span class="p">,</span> <span class="n">arcsec</span><span class="o">=</span><span class="mi">1</span><span class="o">/</span><span class="mf">3600.</span><span class="p">,</span> <span class="n">rad</span><span class="o">=</span><span class="mi">180</span><span class="o">/</span><span class="n">math</span><span class="o">.</span><span class="n">pi</span><span class="p">)</span> |
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| 171 | |
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| 172 | <span class="n">frequency</span> <span class="o">=</span> <span class="n">_build_metric_units</span><span class="p">(</span><span class="s">'hertz'</span><span class="p">,</span><span class="s">'Hz'</span><span class="p">)</span> |
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| 173 | <span class="n">frequency</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">_build_metric_units</span><span class="p">(</span><span class="s">'Hertz'</span><span class="p">,</span><span class="s">'Hz'</span><span class="p">))</span> |
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| 174 | <span class="n">frequency</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">_build_plural_units</span><span class="p">(</span><span class="n">rpm</span><span class="o">=</span><span class="mi">1</span><span class="o">/</span><span class="mf">60.</span><span class="p">))</span> |
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| 175 | |
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| 176 | <span class="c"># Note: degrees are used for angle</span> |
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| 177 | <span class="c"># Note: temperature needs an offset as well as a scale</span> |
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| 178 | <span class="n">temperature</span> <span class="o">=</span> <span class="n">_build_metric_units</span><span class="p">(</span><span class="s">'kelvin'</span><span class="p">,</span><span class="s">'K'</span><span class="p">)</span> |
---|
| 179 | <span class="n">temperature</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">_build_metric_units</span><span class="p">(</span><span class="s">'Kelvin'</span><span class="p">,</span><span class="s">'K'</span><span class="p">))</span> |
---|
| 180 | |
---|
| 181 | <span class="n">charge</span> <span class="o">=</span> <span class="n">_build_metric_units</span><span class="p">(</span><span class="s">'coulomb'</span><span class="p">,</span><span class="s">'C'</span><span class="p">)</span> |
---|
| 182 | <span class="n">charge</span><span class="o">.</span><span class="n">update</span><span class="p">({</span><span class="s">'microAmp*hour'</span><span class="p">:</span><span class="mf">0.0036</span><span class="p">})</span> |
---|
| 183 | |
---|
| 184 | <span class="n">sld</span> <span class="o">=</span> <span class="p">{</span> <span class="s">'10^-6 Angstrom^-2'</span><span class="p">:</span> <span class="mf">1e-6</span><span class="p">,</span> <span class="s">'Angstrom^-2'</span><span class="p">:</span> <span class="mi">1</span> <span class="p">}</span> |
---|
| 185 | <span class="n">Q</span> <span class="o">=</span> <span class="p">{</span> <span class="s">'invA'</span><span class="p">:</span> <span class="mi">1</span><span class="p">,</span> <span class="s">'invAng'</span><span class="p">:</span> <span class="mi">1</span><span class="p">,</span> <span class="s">'invAngstroms'</span><span class="p">:</span> <span class="mi">1</span><span class="p">,</span> <span class="s">'1/A'</span><span class="p">:</span> <span class="mi">1</span><span class="p">,</span> |
---|
| 186 | <span class="s">'10^-3 Angstrom^-1'</span><span class="p">:</span> <span class="mf">1e-3</span><span class="p">,</span> <span class="s">'1/cm'</span><span class="p">:</span> <span class="mf">1e-8</span><span class="p">,</span> |
---|
| 187 | <span class="s">'nm^-1'</span><span class="p">:</span> <span class="mf">0.1</span><span class="p">,</span> <span class="s">'1/nm'</span><span class="p">:</span> <span class="mf">0.1</span><span class="p">,</span> <span class="s">'n_m^-1'</span><span class="p">:</span> <span class="mf">0.1</span> <span class="p">}</span> |
---|
| 188 | |
---|
| 189 | <span class="n">_caret_optional</span><span class="p">(</span><span class="n">sld</span><span class="p">)</span> |
---|
| 190 | <span class="n">_caret_optional</span><span class="p">(</span><span class="n">Q</span><span class="p">)</span> |
---|
| 191 | |
---|
| 192 | <span class="n">dims</span> <span class="o">=</span> <span class="p">[</span><span class="n">distance</span><span class="p">,</span> <span class="n">time</span><span class="p">,</span> <span class="n">angle</span><span class="p">,</span> <span class="n">frequency</span><span class="p">,</span> <span class="n">temperature</span><span class="p">,</span> <span class="n">charge</span><span class="p">,</span> <span class="n">sld</span><span class="p">,</span> <span class="n">Q</span><span class="p">]</span> |
---|
| 193 | <span class="k">return</span> <span class="n">dims</span> |
---|
| 194 | |
---|
| 195 | <div class="viewcode-block" id="Converter"><a class="viewcode-back" href="../../../dev/api/sas.data_util.html#sas.data_util.nxsunit.Converter">[docs]</a><span class="k">class</span> <span class="nc">Converter</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span> |
---|
| 196 | <span class="sd">"""</span> |
---|
| 197 | <span class="sd"> Unit converter for NeXus style units.</span> |
---|
| 198 | |
---|
| 199 | <span class="sd"> """</span> |
---|
| 200 | <span class="c"># Define the units, using both American and European spelling.</span> |
---|
| 201 | <span class="n">scalemap</span> <span class="o">=</span> <span class="bp">None</span> |
---|
| 202 | <span class="n">scalebase</span> <span class="o">=</span> <span class="mi">1</span> |
---|
| 203 | <span class="n">dims</span> <span class="o">=</span> <span class="n">_build_all_units</span><span class="p">()</span> |
---|
| 204 | |
---|
| 205 | <span class="c"># Note: a.u. stands for arbitrary units, which should return the default</span> |
---|
| 206 | <span class="c"># units for that particular dimension.</span> |
---|
| 207 | <span class="c"># Note: don't have support for dimensionless units.</span> |
---|
| 208 | <span class="n">unknown</span> <span class="o">=</span> <span class="p">{</span><span class="bp">None</span><span class="p">:</span><span class="mi">1</span><span class="p">,</span> <span class="s">'???'</span><span class="p">:</span><span class="mi">1</span><span class="p">,</span> <span class="s">''</span><span class="p">:</span> <span class="mi">1</span><span class="p">,</span> <span class="s">'a.u.'</span><span class="p">:</span> <span class="mi">1</span><span class="p">}</span> |
---|
| 209 | |
---|
| 210 | <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">name</span><span class="p">):</span> |
---|
| 211 | <span class="bp">self</span><span class="o">.</span><span class="n">base</span> <span class="o">=</span> <span class="n">name</span> |
---|
| 212 | <span class="k">for</span> <span class="nb">map</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">dims</span><span class="p">:</span> |
---|
| 213 | <span class="k">if</span> <span class="n">name</span> <span class="ow">in</span> <span class="nb">map</span><span class="p">:</span> |
---|
| 214 | <span class="bp">self</span><span class="o">.</span><span class="n">scalemap</span> <span class="o">=</span> <span class="nb">map</span> |
---|
| 215 | <span class="bp">self</span><span class="o">.</span><span class="n">scalebase</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">scalemap</span><span class="p">[</span><span class="n">name</span><span class="p">]</span> |
---|
| 216 | <span class="k">return</span> |
---|
| 217 | <span class="k">if</span> <span class="n">name</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">unknown</span><span class="p">:</span> |
---|
| 218 | <span class="k">return</span> <span class="c"># default scalemap and scalebase correspond to unknown</span> |
---|
| 219 | <span class="k">else</span><span class="p">:</span> |
---|
| 220 | <span class="k">raise</span> <span class="ne">KeyError</span><span class="p">(</span><span class="s">"Unknown unit </span><span class="si">%s</span><span class="s">"</span><span class="o">%</span><span class="n">name</span><span class="p">)</span> |
---|
| 221 | |
---|
| 222 | <div class="viewcode-block" id="Converter.scale"><a class="viewcode-back" href="../../../dev/api/sas.data_util.html#sas.data_util.nxsunit.Converter.scale">[docs]</a> <span class="k">def</span> <span class="nf">scale</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">units</span><span class="o">=</span><span class="s">""</span><span class="p">):</span> |
---|
| 223 | <span class="k">if</span> <span class="n">units</span> <span class="o">==</span> <span class="s">""</span> <span class="ow">or</span> <span class="bp">self</span><span class="o">.</span><span class="n">scalemap</span> <span class="ow">is</span> <span class="bp">None</span><span class="p">:</span> <span class="k">return</span> <span class="mi">1</span> |
---|
| 224 | <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">scalebase</span><span class="o">/</span><span class="bp">self</span><span class="o">.</span><span class="n">scalemap</span><span class="p">[</span><span class="n">units</span><span class="p">]</span> |
---|
| 225 | </div> |
---|
| 226 | <span class="k">def</span> <span class="nf">__call__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">value</span><span class="p">,</span> <span class="n">units</span><span class="o">=</span><span class="s">""</span><span class="p">):</span> |
---|
| 227 | <span class="c"># Note: calculating a*1 rather than simply returning a would produce</span> |
---|
| 228 | <span class="c"># an unnecessary copy of the array, which in the case of the raw</span> |
---|
| 229 | <span class="c"># counts array would be bad. Sometimes copying and other times</span> |
---|
| 230 | <span class="c"># not copying is also bad, but copy on modify semantics isn't</span> |
---|
| 231 | <span class="c"># supported.</span> |
---|
| 232 | <span class="k">if</span> <span class="n">units</span> <span class="o">==</span> <span class="s">""</span> <span class="ow">or</span> <span class="bp">self</span><span class="o">.</span><span class="n">scalemap</span> <span class="ow">is</span> <span class="bp">None</span><span class="p">:</span> <span class="k">return</span> <span class="n">value</span> |
---|
| 233 | <span class="k">try</span><span class="p">:</span> |
---|
| 234 | <span class="k">return</span> <span class="n">value</span> <span class="o">*</span> <span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">scalebase</span><span class="o">/</span><span class="bp">self</span><span class="o">.</span><span class="n">scalemap</span><span class="p">[</span><span class="n">units</span><span class="p">])</span> |
---|
| 235 | <span class="k">except</span> <span class="ne">KeyError</span><span class="p">:</span> |
---|
| 236 | <span class="n">possible_units</span> <span class="o">=</span> <span class="s">", "</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="nb">str</span><span class="p">(</span><span class="n">k</span><span class="p">)</span> <span class="k">for</span> <span class="n">k</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">scalemap</span><span class="o">.</span><span class="n">keys</span><span class="p">())</span> |
---|
| 237 | <span class="k">raise</span> <span class="ne">KeyError</span><span class="p">(</span><span class="s">"</span><span class="si">%s</span><span class="s"> not in </span><span class="si">%s</span><span class="s">"</span><span class="o">%</span><span class="p">(</span><span class="n">units</span><span class="p">,</span><span class="n">possible_units</span><span class="p">))</span> |
---|
| 238 | </div> |
---|
| 239 | <span class="k">def</span> <span class="nf">_check</span><span class="p">(</span><span class="n">expect</span><span class="p">,</span><span class="n">get</span><span class="p">):</span> |
---|
| 240 | <span class="k">if</span> <span class="n">expect</span> <span class="o">!=</span> <span class="n">get</span><span class="p">:</span> <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">,</span> <span class="s">"Expected </span><span class="si">%s</span><span class="s"> but got </span><span class="si">%s</span><span class="s">"</span><span class="o">%</span><span class="p">(</span><span class="n">expect</span><span class="p">,</span><span class="n">get</span><span class="p">)</span> |
---|
| 241 | <span class="c">#print expect,"==",get</span> |
---|
| 242 | |
---|
| 243 | <span class="k">def</span> <span class="nf">test</span><span class="p">():</span> |
---|
| 244 | <span class="n">_check</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="n">Converter</span><span class="p">(</span><span class="s">'n_m^-1'</span><span class="p">)(</span><span class="mi">10</span><span class="p">,</span><span class="s">'invA'</span><span class="p">))</span> <span class="c"># 10 nm^-1 = 1 inv Angstroms</span> |
---|
| 245 | <span class="n">_check</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span><span class="n">Converter</span><span class="p">(</span><span class="s">'mm'</span><span class="p">)(</span><span class="mi">2000</span><span class="p">,</span><span class="s">'m'</span><span class="p">))</span> <span class="c"># 2000 mm -> 2 m</span> |
---|
| 246 | <span class="n">_check</span><span class="p">(</span><span class="mf">0.003</span><span class="p">,</span><span class="n">Converter</span><span class="p">(</span><span class="s">'microseconds'</span><span class="p">)(</span><span class="mi">3</span><span class="p">,</span><span class="n">units</span><span class="o">=</span><span class="s">'ms'</span><span class="p">))</span> <span class="c"># 3 us -> 0.003 ms</span> |
---|
| 247 | <span class="n">_check</span><span class="p">(</span><span class="mi">45</span><span class="p">,</span><span class="n">Converter</span><span class="p">(</span><span class="s">'nanokelvin'</span><span class="p">)(</span><span class="mi">45</span><span class="p">))</span> <span class="c"># 45 nK -> 45 nK</span> |
---|
| 248 | <span class="n">_check</span><span class="p">(</span><span class="mf">0.5</span><span class="p">,</span><span class="n">Converter</span><span class="p">(</span><span class="s">'seconds'</span><span class="p">)(</span><span class="mi">1800</span><span class="p">,</span><span class="n">units</span><span class="o">=</span><span class="s">'hours'</span><span class="p">))</span> <span class="c"># 1800 s -> 0.5 hr</span> |
---|
| 249 | <span class="n">_check</span><span class="p">(</span><span class="mi">123</span><span class="p">,</span><span class="n">Converter</span><span class="p">(</span><span class="s">'a.u.'</span><span class="p">)(</span><span class="mi">123</span><span class="p">,</span><span class="n">units</span><span class="o">=</span><span class="s">'mm'</span><span class="p">))</span> <span class="c"># arbitrary units always returns the same value</span> |
---|
| 250 | <span class="n">_check</span><span class="p">(</span><span class="mi">123</span><span class="p">,</span><span class="n">Converter</span><span class="p">(</span><span class="s">'a.u.'</span><span class="p">)(</span><span class="mi">123</span><span class="p">,</span><span class="n">units</span><span class="o">=</span><span class="s">'s'</span><span class="p">))</span> <span class="c"># arbitrary units always returns the same value</span> |
---|
| 251 | <span class="n">_check</span><span class="p">(</span><span class="mi">123</span><span class="p">,</span><span class="n">Converter</span><span class="p">(</span><span class="s">'a.u.'</span><span class="p">)(</span><span class="mi">123</span><span class="p">,</span><span class="n">units</span><span class="o">=</span><span class="s">''</span><span class="p">))</span> <span class="c"># arbitrary units always returns the same value</span> |
---|
| 252 | <span class="k">try</span><span class="p">:</span> <span class="n">Converter</span><span class="p">(</span><span class="s">'help'</span><span class="p">)</span> |
---|
| 253 | <span class="k">except</span> <span class="ne">KeyError</span><span class="p">:</span> <span class="k">pass</span> |
---|
| 254 | <span class="k">else</span><span class="p">:</span> <span class="k">raise</span> <span class="ne">Exception</span><span class="p">(</span><span class="s">"unknown unit did not raise an error"</span><span class="p">)</span> |
---|
| 255 | |
---|
| 256 | <span class="c"># TODO: more tests</span> |
---|
| 257 | |
---|
| 258 | <span class="k">if</span> <span class="n">__name__</span> <span class="o">==</span> <span class="s">"__main__"</span><span class="p">:</span> |
---|
| 259 | <span class="n">test</span><span class="p">()</span> |
---|
| 260 | </pre></div> |
---|
| 261 | |
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| 262 | </div> |
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| 263 | </div> |
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| 264 | </div> |
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| 265 | <div class="sphinxsidebar"> |
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| 266 | <div class="sphinxsidebarwrapper"> |
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| 268 | <h3>Quick search</h3> |
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| 269 | <form class="search" action="../../../search.html" method="get"> |
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| 276 | Enter search terms or a module, class or function name. |
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| 277 | </p> |
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| 278 | </div> |
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| 279 | <script type="text/javascript">$('#searchbox').show(0);</script> |
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| 285 | <h3>Navigation</h3> |
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| 289 | >index</a></li> |
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