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50  <h1>Source code for park.expression</h1><div class="highlight"><pre>
51<span class="c"># This program is public domain</span>
52<span class="sd">&quot;&quot;&quot;</span>
53<span class="sd">Functions for manipulating expressions.   </span>
54<span class="sd">&quot;&quot;&quot;</span>
55<span class="kn">import</span> <span class="nn">math</span>
56<span class="kn">import</span> <span class="nn">re</span>
57<span class="kn">from</span> <span class="nn">deps</span> <span class="kn">import</span> <span class="n">order_dependencies</span>
58
59<span class="c"># simple pattern which matches symbols.  Note that it will also match</span>
60<span class="c"># invalid substrings such as a3...9, but given syntactically correct</span>
61<span class="c"># input it will only match symbols.</span>
62<span class="n">_symbol_pattern</span> <span class="o">=</span> <span class="n">re</span><span class="o">.</span><span class="n">compile</span><span class="p">(</span><span class="s">&#39;([a-zA-Z][a-zA-Z_0-9.]*)&#39;</span><span class="p">)</span>
63
64<div class="viewcode-block" id="symbols"><a class="viewcode-back" href="../../dev/api/park.html#park.expression.symbols">[docs]</a><span class="k">def</span> <span class="nf">symbols</span><span class="p">(</span><span class="n">expr</span><span class="p">,</span><span class="n">symtab</span><span class="p">):</span>
65    <span class="sd">&quot;&quot;&quot;</span>
66<span class="sd">    Given an expression string and a symbol table, return the set of symbols</span>
67<span class="sd">    used in the expression.  Symbols are only returned once even if they</span>
68<span class="sd">    occur multiple times.  The return value is a set with the elements in</span>
69<span class="sd">    no particular order.</span>
70<span class="sd">    </span>
71<span class="sd">    This is the first step in computing a dependency graph.</span>
72<span class="sd">    &quot;&quot;&quot;</span>
73    <span class="n">matches</span> <span class="o">=</span> <span class="p">[</span><span class="n">m</span><span class="o">.</span><span class="n">group</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span> <span class="k">for</span> <span class="n">m</span> <span class="ow">in</span> <span class="n">_symbol_pattern</span><span class="o">.</span><span class="n">finditer</span><span class="p">(</span><span class="n">expr</span><span class="p">)]</span>
74    <span class="k">return</span> <span class="nb">set</span><span class="p">([</span><span class="n">symtab</span><span class="p">[</span><span class="n">m</span><span class="p">]</span> <span class="k">for</span> <span class="n">m</span> <span class="ow">in</span> <span class="n">matches</span> <span class="k">if</span> <span class="n">m</span> <span class="ow">in</span> <span class="n">symtab</span><span class="p">])</span>
75</div>
76<div class="viewcode-block" id="substitute"><a class="viewcode-back" href="../../dev/api/park.html#park.expression.substitute">[docs]</a><span class="k">def</span> <span class="nf">substitute</span><span class="p">(</span><span class="n">expr</span><span class="p">,</span><span class="n">mapping</span><span class="p">):</span>
77    <span class="sd">&quot;&quot;&quot;</span>
78<span class="sd">    Replace all occurrences of symbol s with mapping[s] for s in mapping.</span>
79<span class="sd">    &quot;&quot;&quot;</span>
80    <span class="c"># Find the symbols and the mapping</span>
81    <span class="n">matches</span> <span class="o">=</span> <span class="p">[(</span><span class="n">m</span><span class="o">.</span><span class="n">start</span><span class="p">(),</span><span class="n">m</span><span class="o">.</span><span class="n">end</span><span class="p">(),</span><span class="n">mapping</span><span class="p">[</span><span class="n">m</span><span class="o">.</span><span class="n">group</span><span class="p">(</span><span class="mi">1</span><span class="p">)])</span>
82               <span class="k">for</span> <span class="n">m</span> <span class="ow">in</span> <span class="n">_symbol_pattern</span><span class="o">.</span><span class="n">finditer</span><span class="p">(</span><span class="n">expr</span><span class="p">)</span>
83               <span class="k">if</span> <span class="n">m</span><span class="o">.</span><span class="n">group</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span> <span class="ow">in</span> <span class="n">mapping</span><span class="p">]</span>
84   
85    <span class="c"># Split the expression in to pieces, with new symbols replacing old</span>
86    <span class="n">pieces</span> <span class="o">=</span> <span class="p">[]</span>
87    <span class="n">offset</span> <span class="o">=</span> <span class="mi">0</span>
88    <span class="k">for</span> <span class="n">start</span><span class="p">,</span><span class="n">end</span><span class="p">,</span><span class="n">text</span> <span class="ow">in</span> <span class="n">matches</span><span class="p">:</span>
89        <span class="n">pieces</span> <span class="o">+=</span> <span class="p">[</span><span class="n">expr</span><span class="p">[</span><span class="n">offset</span><span class="p">:</span><span class="n">start</span><span class="p">],</span><span class="n">text</span><span class="p">]</span>
90        <span class="n">offset</span> <span class="o">=</span> <span class="n">end</span>
91    <span class="n">pieces</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">expr</span><span class="p">[</span><span class="n">offset</span><span class="p">:])</span>
92   
93    <span class="c"># Join the pieces and return them</span>
94    <span class="k">return</span> <span class="s">&quot;&quot;</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">pieces</span><span class="p">)</span>
95</div>
96<div class="viewcode-block" id="find_dependencies"><a class="viewcode-back" href="../../dev/api/park.html#park.expression.find_dependencies">[docs]</a><span class="k">def</span> <span class="nf">find_dependencies</span><span class="p">(</span><span class="n">pars</span><span class="p">):</span>
97    <span class="sd">&quot;&quot;&quot;</span>
98<span class="sd">    Returns a list of pair-wise dependencies from the parameter expressions.</span>
99<span class="sd">    </span>
100<span class="sd">    For example, if p3 = p1+p2, then find_dependencies([p1,p2,p3]) will</span>
101<span class="sd">    return [(p3,p1),(p3,p2)].  For base expressions without dependencies,</span>
102<span class="sd">    such as p4 = 2*pi, this should return [(p4, None)]</span>
103<span class="sd">    &quot;&quot;&quot;</span>
104    <span class="n">symtab</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="n">path</span><span class="p">,</span> <span class="n">p</span><span class="p">)</span> <span class="k">for</span> <span class="n">p</span> <span class="ow">in</span> <span class="n">pars</span><span class="p">])</span>
105    <span class="c"># Hack to deal with expressions without dependencies --- return a fake</span>
106    <span class="c"># dependency of None.  </span>
107    <span class="c"># The better solution is fix order_dependencies so that it takes a </span>
108    <span class="c"># dictionary of {symbol: dependency_list}, for which no dependencies </span>
109    <span class="c"># is simply []; fix in parameter_mapping as well</span>
110    <span class="k">def</span> <span class="nf">symbols_or_none</span><span class="p">(</span><span class="n">expr</span><span class="p">,</span><span class="n">symtab</span><span class="p">):</span>
111        <span class="n">syms</span> <span class="o">=</span> <span class="n">symbols</span><span class="p">(</span><span class="n">expr</span><span class="p">,</span><span class="n">symtab</span><span class="p">)</span>
112        <span class="k">return</span> <span class="n">syms</span> <span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">syms</span><span class="p">)</span> <span class="k">else</span> <span class="p">[</span><span class="bp">None</span><span class="p">]</span>
113    <span class="n">deps</span> <span class="o">=</span> <span class="p">[(</span><span class="n">p</span><span class="p">,</span><span class="n">dep</span><span class="p">)</span> 
114            <span class="k">for</span> <span class="n">p</span> <span class="ow">in</span> <span class="n">pars</span> <span class="k">if</span> <span class="n">p</span><span class="o">.</span><span class="n">iscomputed</span><span class="p">()</span>
115            <span class="k">for</span> <span class="n">dep</span> <span class="ow">in</span> <span class="n">symbols_or_none</span><span class="p">(</span><span class="n">p</span><span class="o">.</span><span class="n">expression</span><span class="p">,</span><span class="n">symtab</span><span class="p">)]</span>
116    <span class="k">return</span> <span class="n">deps</span>
117</div>
118<div class="viewcode-block" id="parameter_mapping"><a class="viewcode-back" href="../../dev/api/park.html#park.expression.parameter_mapping">[docs]</a><span class="k">def</span> <span class="nf">parameter_mapping</span><span class="p">(</span><span class="n">pairs</span><span class="p">):</span>
119    <span class="sd">&quot;&quot;&quot;</span>
120<span class="sd">    Find the parameter substitution we need so that expressions can</span>
121<span class="sd">    be evaluated without having to traverse a chain of </span>
122<span class="sd">    model.layer.parameter.value</span>
123<span class="sd">    &quot;&quot;&quot;</span>
124    <span class="n">left</span><span class="p">,</span><span class="n">right</span> <span class="o">=</span> <span class="nb">zip</span><span class="p">(</span><span class="o">*</span><span class="n">pairs</span><span class="p">)</span>
125    <span class="n">pars</span> <span class="o">=</span> <span class="nb">set</span><span class="p">(</span><span class="n">left</span><span class="o">+</span><span class="n">right</span><span class="p">)</span>
126    <span class="n">symtab</span> <span class="o">=</span> <span class="nb">dict</span><span class="p">(</span> <span class="p">(</span><span class="s">&#39;P</span><span class="si">%d</span><span class="s">&#39;</span><span class="o">%</span><span class="n">i</span><span class="p">,</span><span class="n">p</span><span class="p">)</span> <span class="k">for</span> <span class="n">i</span><span class="p">,</span><span class="n">p</span> <span class="ow">in</span> <span class="nb">enumerate</span><span class="p">(</span><span class="n">pars</span><span class="p">)</span> <span class="p">)</span>
127    <span class="c"># p is None when there is an expression with no dependencies</span>
128    <span class="n">mapping</span> <span class="o">=</span> <span class="nb">dict</span><span class="p">(</span> <span class="p">(</span><span class="n">p</span><span class="o">.</span><span class="n">path</span><span class="p">,</span><span class="s">&#39;P</span><span class="si">%d</span><span class="s">.value&#39;</span><span class="o">%</span><span class="n">i</span><span class="p">)</span> 
129                    <span class="k">for</span> <span class="n">i</span><span class="p">,</span><span class="n">p</span> <span class="ow">in</span> <span class="nb">enumerate</span><span class="p">(</span><span class="n">pars</span><span class="p">)</span> 
130                    <span class="k">if</span> <span class="n">p</span> <span class="ow">is</span> <span class="ow">not</span> <span class="bp">None</span><span class="p">)</span>
131    <span class="k">return</span> <span class="n">symtab</span><span class="p">,</span><span class="n">mapping</span>
132</div>
133<div class="viewcode-block" id="no_constraints"><a class="viewcode-back" href="../../dev/api/park.html#park.expression.no_constraints">[docs]</a><span class="k">def</span> <span class="nf">no_constraints</span><span class="p">():</span> 
134    <span class="sd">&quot;&quot;&quot;</span>
135<span class="sd">    This parameter set has no constraints between the parameters.</span>
136<span class="sd">    &quot;&quot;&quot;</span>
137    <span class="k">pass</span>
138</div>
139<div class="viewcode-block" id="build_eval"><a class="viewcode-back" href="../../dev/api/park.html#park.expression.build_eval">[docs]</a><span class="k">def</span> <span class="nf">build_eval</span><span class="p">(</span><span class="n">pars</span><span class="p">,</span> <span class="n">context</span><span class="o">=</span><span class="p">{}):</span>
140    <span class="sd">&quot;&quot;&quot;</span>
141<span class="sd">    Build and return a function to evaluate all parameter expressions in</span>
142<span class="sd">    the proper order.</span>
143<span class="sd">    </span>
144<span class="sd">    Inputs:</span>
145<span class="sd">        pars is a list of parameters</span>
146<span class="sd">        context is a dictionary of additional symbols for the expressions</span>
147
148<span class="sd">    Output:</span>
149<span class="sd">        updater function</span>
150
151<span class="sd">    Raises:</span>
152<span class="sd">       AssertionError - model, parameter or function is missing</span>
153<span class="sd">       SyntaxError - improper expression syntax</span>
154<span class="sd">       ValueError - expressions have circular dependencies</span>
155
156<span class="sd">    This function is not terribly sophisticated, and it would be easy to</span>
157<span class="sd">    trick.  However it handles the common cases cleanly and generates</span>
158<span class="sd">    reasonable messages for the common errors.</span>
159
160<span class="sd">    This code has not been fully audited for security.  While we have</span>
161<span class="sd">    removed the builtins and the ability to import modules, there may</span>
162<span class="sd">    be other vectors for users to perform more than simple function</span>
163<span class="sd">    evaluations.  Unauthenticated users should not be running this code.</span>
164
165<span class="sd">    Parameter names are assumed to contain only _.a-zA-Z0-9#[]</span>
166<span class="sd">    </span>
167<span class="sd">    The list of parameters is probably something like::</span>
168<span class="sd">    </span>
169<span class="sd">        parset.setprefix()</span>
170<span class="sd">        pars = parset.flatten()</span>
171<span class="sd">    </span>
172<span class="sd">    Note that math uses acos while numpy uses arccos.  To avoid confusion</span>
173<span class="sd">    we allow both.</span>
174<span class="sd">    </span>
175<span class="sd">    Should try running the function to identify syntax errors before</span>
176<span class="sd">    running it in a fit.</span>
177<span class="sd">    </span>
178<span class="sd">    Use help(fn) to see the code generated for the returned function fn.</span>
179<span class="sd">    dis.dis(fn) will show the corresponding python vm instructions.</span>
180<span class="sd">    &quot;&quot;&quot;</span>
181
182    <span class="c"># Initialize dictionary with available functions</span>
183    <span class="nb">globals</span> <span class="o">=</span> <span class="p">{}</span>
184    <span class="nb">globals</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">math</span><span class="o">.</span><span class="n">__dict__</span><span class="p">)</span>
185    <span class="nb">globals</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="nb">dict</span><span class="p">(</span><span class="n">arcsin</span><span class="o">=</span><span class="n">math</span><span class="o">.</span><span class="n">asin</span><span class="p">,</span><span class="n">arccos</span><span class="o">=</span><span class="n">math</span><span class="o">.</span><span class="n">acos</span><span class="p">,</span>
186                        <span class="n">arctan</span><span class="o">=</span><span class="n">math</span><span class="o">.</span><span class="n">atan</span><span class="p">,</span><span class="n">arctan2</span><span class="o">=</span><span class="n">math</span><span class="o">.</span><span class="n">atan2</span><span class="p">))</span>
187    <span class="nb">globals</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">context</span><span class="p">)</span>
188
189    <span class="c"># Sort the parameters in the order they need to be evaluated</span>
190    <span class="n">deps</span> <span class="o">=</span> <span class="n">find_dependencies</span><span class="p">(</span><span class="n">pars</span><span class="p">)</span>
191    <span class="k">if</span> <span class="n">deps</span> <span class="o">==</span> <span class="p">[]:</span> <span class="k">return</span> <span class="n">no_constraints</span>
192    <span class="n">par_table</span><span class="p">,</span><span class="n">par_mapping</span> <span class="o">=</span> <span class="n">parameter_mapping</span><span class="p">(</span><span class="n">deps</span><span class="p">)</span>
193    <span class="n">order</span> <span class="o">=</span> <span class="n">order_dependencies</span><span class="p">(</span><span class="n">deps</span><span class="p">)</span>
194   
195    <span class="c"># Finish setting up the global and local namespace</span>
196    <span class="nb">globals</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">par_table</span><span class="p">)</span>
197    <span class="nb">locals</span> <span class="o">=</span> <span class="p">{}</span>
198
199    <span class="c"># Define the function body</span>
200    <span class="n">exprs</span> <span class="o">=</span> <span class="p">[</span><span class="n">p</span><span class="o">.</span><span class="n">path</span><span class="o">+</span><span class="s">&quot;=&quot;</span><span class="o">+</span><span class="n">p</span><span class="o">.</span><span class="n">expression</span> <span class="k">for</span> <span class="n">p</span> <span class="ow">in</span> <span class="n">order</span><span class="p">]</span>
201    <span class="n">code</span> <span class="o">=</span> <span class="p">[</span><span class="n">substitute</span><span class="p">(</span><span class="n">s</span><span class="p">,</span><span class="n">par_mapping</span><span class="p">)</span> <span class="k">for</span> <span class="n">s</span> <span class="ow">in</span> <span class="n">exprs</span><span class="p">]</span>
202       
203    <span class="c"># Define the constraints function</span>
204    <span class="n">functiondef</span> <span class="o">=</span> <span class="s">&quot;&quot;&quot;</span>
205<span class="s">def eval_expressions():</span>
206<span class="s">    &#39;&#39;&#39;</span>
207<span class="s">    </span><span class="si">%s</span><span class="s"></span>
208<span class="s">    &#39;&#39;&#39;</span>
209<span class="s">    </span><span class="si">%s</span><span class="s"></span>
210<span class="s">&quot;&quot;&quot;</span><span class="o">%</span><span class="p">(</span><span class="s">&quot;</span><span class="se">\n</span><span class="s">    &quot;</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">exprs</span><span class="p">),</span><span class="s">&quot;</span><span class="se">\n</span><span class="s">    &quot;</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">code</span><span class="p">))</span>
211
212    <span class="c">#print &quot;Function:&quot;,functiondef</span>
213    <span class="k">exec</span> <span class="n">functiondef</span> <span class="ow">in</span> <span class="nb">globals</span><span class="p">,</span><span class="nb">locals</span>
214    <span class="n">retfn</span> <span class="o">=</span> <span class="nb">locals</span><span class="p">[</span><span class="s">&#39;eval_expressions&#39;</span><span class="p">]</span>
215
216    <span class="c"># Remove garbage added to globals by exec</span>
217    <span class="nb">globals</span><span class="o">.</span><span class="n">pop</span><span class="p">(</span><span class="s">&#39;__doc__&#39;</span><span class="p">,</span><span class="bp">None</span><span class="p">)</span>
218    <span class="nb">globals</span><span class="o">.</span><span class="n">pop</span><span class="p">(</span><span class="s">&#39;__name__&#39;</span><span class="p">,</span><span class="bp">None</span><span class="p">)</span>
219    <span class="nb">globals</span><span class="o">.</span><span class="n">pop</span><span class="p">(</span><span class="s">&#39;__file__&#39;</span><span class="p">,</span><span class="bp">None</span><span class="p">)</span>
220    <span class="nb">globals</span><span class="o">.</span><span class="n">pop</span><span class="p">(</span><span class="s">&#39;__builtins__&#39;</span><span class="p">)</span>
221    <span class="c">#print globals.keys()</span>
222
223    <span class="k">return</span> <span class="n">retfn</span>
224</div>
225<div class="viewcode-block" id="test"><a class="viewcode-back" href="../../dev/api/park.html#park.expression.test">[docs]</a><span class="k">def</span> <span class="nf">test</span><span class="p">():</span>
226    <span class="kn">import</span> <span class="nn">inspect</span><span class="o">,</span> <span class="nn">dis</span>
227    <span class="kn">import</span> <span class="nn">math</span>
228   
229    <span class="n">symtab</span> <span class="o">=</span> <span class="p">{</span><span class="s">&#39;a.b.x&#39;</span><span class="p">:</span><span class="mi">1</span><span class="p">,</span> <span class="s">&#39;a.c&#39;</span><span class="p">:</span><span class="mi">2</span><span class="p">,</span> <span class="s">&#39;a.b&#39;</span><span class="p">:</span><span class="mi">3</span><span class="p">,</span> <span class="s">&#39;b.x&#39;</span><span class="p">:</span><span class="mi">4</span><span class="p">}</span>
230    <span class="n">expr</span> <span class="o">=</span> <span class="s">&#39;a.b.x + sin(4*pi*a.c) + a.b.x/a.b&#39;</span>
231   
232    <span class="c"># Check symbol lookup</span>
233    <span class="k">assert</span> <span class="n">symbols</span><span class="p">(</span><span class="n">expr</span><span class="p">,</span> <span class="n">symtab</span><span class="p">)</span> <span class="o">==</span> <span class="nb">set</span><span class="p">([</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">])</span>
234
235    <span class="c"># Check symbol rename</span>
236    <span class="k">assert</span> <span class="n">substitute</span><span class="p">(</span><span class="n">expr</span><span class="p">,{</span><span class="s">&#39;a.b.x&#39;</span><span class="p">:</span><span class="s">&#39;Q&#39;</span><span class="p">})</span> <span class="o">==</span> <span class="s">&#39;Q + sin(4*pi*a.c) + Q/a.b&#39;</span>
237    <span class="k">assert</span> <span class="n">substitute</span><span class="p">(</span><span class="n">expr</span><span class="p">,{</span><span class="s">&#39;a.b&#39;</span><span class="p">:</span><span class="s">&#39;Q&#39;</span><span class="p">})</span> <span class="o">==</span> <span class="s">&#39;a.b.x + sin(4*pi*a.c) + a.b.x/Q&#39;</span>
238
239
240    <span class="c"># Check dependency builder</span>
241    <span class="c"># Fake parameter class</span>
242    <span class="k">class</span> <span class="nc">Parameter</span><span class="p">:</span>
243        <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> <span class="n">value</span><span class="o">=</span><span class="mi">0</span><span class="p">,</span> <span class="n">expression</span><span class="o">=</span><span class="s">&#39;&#39;</span><span class="p">):</span>
244            <span class="bp">self</span><span class="o">.</span><span class="n">path</span> <span class="o">=</span> <span class="n">name</span>
245            <span class="bp">self</span><span class="o">.</span><span class="n">value</span> <span class="o">=</span> <span class="n">value</span>
246            <span class="bp">self</span><span class="o">.</span><span class="n">expression</span> <span class="o">=</span> <span class="n">expression</span>
247        <span class="k">def</span> <span class="nf">iscomputed</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="k">return</span> <span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">expression</span> <span class="o">!=</span> <span class="s">&#39;&#39;</span><span class="p">)</span>
248        <span class="k">def</span> <span class="nf">__repr__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">path</span>
249    <span class="n">p1</span> <span class="o">=</span> <span class="n">Parameter</span><span class="p">(</span><span class="s">&#39;G0.sigma&#39;</span><span class="p">,</span><span class="mi">5</span><span class="p">)</span>
250    <span class="n">p2</span> <span class="o">=</span> <span class="n">Parameter</span><span class="p">(</span><span class="s">&#39;other&#39;</span><span class="p">,</span><span class="n">expression</span><span class="o">=</span><span class="s">&#39;2*pi*sin(G0.sigma/.1875) + M1.G1&#39;</span><span class="p">)</span>
251    <span class="n">p3</span> <span class="o">=</span> <span class="n">Parameter</span><span class="p">(</span><span class="s">&#39;M1.G1&#39;</span><span class="p">,</span><span class="mi">6</span><span class="p">)</span>
252    <span class="n">p4</span> <span class="o">=</span> <span class="n">Parameter</span><span class="p">(</span><span class="s">&#39;constant&#39;</span><span class="p">,</span><span class="n">expression</span><span class="o">=</span><span class="s">&#39;2*pi*35&#39;</span><span class="p">)</span>
253    <span class="c"># Simple chain</span>
254    <span class="k">assert</span> <span class="nb">set</span><span class="p">(</span><span class="n">find_dependencies</span><span class="p">([</span><span class="n">p1</span><span class="p">,</span><span class="n">p2</span><span class="p">,</span><span class="n">p3</span><span class="p">]))</span> <span class="o">==</span> <span class="nb">set</span><span class="p">([(</span><span class="n">p2</span><span class="p">,</span><span class="n">p1</span><span class="p">),(</span><span class="n">p2</span><span class="p">,</span><span class="n">p3</span><span class="p">)])</span>
255    <span class="c"># Constant expression</span>
256    <span class="k">assert</span> <span class="nb">set</span><span class="p">(</span><span class="n">find_dependencies</span><span class="p">([</span><span class="n">p1</span><span class="p">,</span><span class="n">p4</span><span class="p">]))</span> <span class="o">==</span> <span class="nb">set</span><span class="p">([(</span><span class="n">p4</span><span class="p">,</span><span class="bp">None</span><span class="p">)])</span>
257    <span class="c"># No dependencies</span>
258    <span class="k">assert</span> <span class="nb">set</span><span class="p">(</span><span class="n">find_dependencies</span><span class="p">([</span><span class="n">p1</span><span class="p">,</span><span class="n">p3</span><span class="p">]))</span> <span class="o">==</span> <span class="nb">set</span><span class="p">([])</span>
259
260    <span class="c"># Check function builder</span>
261    <span class="n">fn</span> <span class="o">=</span> <span class="n">build_eval</span><span class="p">([</span><span class="n">p1</span><span class="p">,</span><span class="n">p2</span><span class="p">,</span><span class="n">p3</span><span class="p">])</span>
262
263    <span class="c"># Inspect the resulting function</span>
264    <span class="k">if</span> <span class="bp">False</span><span class="p">:</span>
265        <span class="k">print</span> <span class="n">inspect</span><span class="o">.</span><span class="n">getdoc</span><span class="p">(</span><span class="n">fn</span><span class="p">)</span>
266        <span class="k">print</span> <span class="n">dis</span><span class="o">.</span><span class="n">dis</span><span class="p">(</span><span class="n">fn</span><span class="p">)</span>
267
268    <span class="c"># Evaluate the function and see if it updates the</span>
269    <span class="c"># target value as expected</span>
270    <span class="n">fn</span><span class="p">()</span>
271    <span class="n">expected</span> <span class="o">=</span> <span class="mi">2</span><span class="o">*</span><span class="n">math</span><span class="o">.</span><span class="n">pi</span><span class="o">*</span><span class="n">math</span><span class="o">.</span><span class="n">sin</span><span class="p">(</span><span class="mi">5</span><span class="o">/.</span><span class="mi">1875</span><span class="p">)</span> <span class="o">+</span> <span class="mi">6</span>
272    <span class="k">assert</span> <span class="n">p2</span><span class="o">.</span><span class="n">value</span> <span class="o">==</span> <span class="n">expected</span><span class="p">,</span><span class="s">&quot;Value was </span><span class="si">%s</span><span class="s">, not </span><span class="si">%s</span><span class="s">&quot;</span><span class="o">%</span><span class="p">(</span><span class="n">p2</span><span class="o">.</span><span class="n">value</span><span class="p">,</span><span class="n">expected</span><span class="p">)</span>
273   
274    <span class="c"># Check empty dependency set doesn&#39;t crash</span>
275    <span class="n">fn</span> <span class="o">=</span> <span class="n">build_eval</span><span class="p">([</span><span class="n">p1</span><span class="p">,</span><span class="n">p3</span><span class="p">])</span>
276    <span class="n">fn</span><span class="p">()</span>
277
278    <span class="c"># Check that constants are evaluated properly</span>
279    <span class="n">fn</span> <span class="o">=</span> <span class="n">build_eval</span><span class="p">([</span><span class="n">p4</span><span class="p">])</span>
280    <span class="n">fn</span><span class="p">()</span>
281    <span class="k">assert</span> <span class="n">p4</span><span class="o">.</span><span class="n">value</span> <span class="o">==</span> <span class="mi">2</span><span class="o">*</span><span class="n">math</span><span class="o">.</span><span class="n">pi</span><span class="o">*</span><span class="mi">35</span>
282
283    <span class="c"># Check additional context example; this also tests multiple</span>
284    <span class="c"># expressions</span>
285    <span class="k">class</span> <span class="nc">Table</span><span class="p">:</span>
286        <span class="n">Si</span> <span class="o">=</span> <span class="mf">2.09</span>
287        <span class="n">values</span> <span class="o">=</span> <span class="p">{</span><span class="s">&#39;Si&#39;</span><span class="p">:</span> <span class="mf">2.07</span><span class="p">}</span>
288    <span class="n">tbl</span> <span class="o">=</span> <span class="n">Table</span><span class="p">()</span>
289    <span class="n">p5</span> <span class="o">=</span> <span class="n">Parameter</span><span class="p">(</span><span class="s">&#39;lookup&#39;</span><span class="p">,</span><span class="n">expression</span><span class="o">=</span><span class="s">&quot;tbl.Si&quot;</span><span class="p">)</span>
290    <span class="n">fn</span> <span class="o">=</span> <span class="n">build_eval</span><span class="p">([</span><span class="n">p1</span><span class="p">,</span><span class="n">p2</span><span class="p">,</span><span class="n">p3</span><span class="p">,</span><span class="n">p5</span><span class="p">],</span><span class="n">context</span><span class="o">=</span><span class="nb">dict</span><span class="p">(</span><span class="n">tbl</span><span class="o">=</span><span class="n">tbl</span><span class="p">))</span>
291    <span class="n">fn</span><span class="p">()</span>
292    <span class="k">assert</span> <span class="n">p5</span><span class="o">.</span><span class="n">value</span> <span class="o">==</span> <span class="mf">2.09</span><span class="p">,</span><span class="s">&quot;Value for </span><span class="si">%s</span><span class="s"> was </span><span class="si">%s</span><span class="s">&quot;</span><span class="o">%</span><span class="p">(</span><span class="n">p5</span><span class="o">.</span><span class="n">expression</span><span class="p">,</span><span class="n">p5</span><span class="o">.</span><span class="n">value</span><span class="p">)</span>
293    <span class="n">p5</span><span class="o">.</span><span class="n">expression</span> <span class="o">=</span> <span class="s">&quot;tbl.values[&#39;Si&#39;]&quot;</span>
294    <span class="n">fn</span> <span class="o">=</span> <span class="n">build_eval</span><span class="p">([</span><span class="n">p1</span><span class="p">,</span><span class="n">p2</span><span class="p">,</span><span class="n">p3</span><span class="p">,</span><span class="n">p5</span><span class="p">],</span><span class="n">context</span><span class="o">=</span><span class="nb">dict</span><span class="p">(</span><span class="n">tbl</span><span class="o">=</span><span class="n">tbl</span><span class="p">))</span>
295    <span class="n">fn</span><span class="p">()</span>
296    <span class="k">assert</span> <span class="n">p5</span><span class="o">.</span><span class="n">value</span> <span class="o">==</span> <span class="mf">2.07</span><span class="p">,</span><span class="s">&quot;Value for </span><span class="si">%s</span><span class="s"> was </span><span class="si">%s</span><span class="s">&quot;</span><span class="o">%</span><span class="p">(</span><span class="n">p5</span><span class="o">.</span><span class="n">expression</span><span class="p">,</span><span class="n">p5</span><span class="o">.</span><span class="n">value</span><span class="p">)</span>
297   
298
299    <span class="c"># Verify that we capture invalid expressions</span>
300    <span class="k">for</span> <span class="n">expr</span> <span class="ow">in</span> <span class="p">[</span><span class="s">&#39;G4.cage&#39;</span><span class="p">,</span> <span class="s">&#39;M0.cage&#39;</span><span class="p">,</span> <span class="s">&#39;M1.G1 + *2&#39;</span><span class="p">,</span> 
301                 <span class="s">&#39;piddle&#39;</span><span class="p">,</span>
302                 <span class="s">&#39;5; import sys; print &quot;p0wned&quot;&#39;</span><span class="p">,</span>
303                 <span class="s">&#39;__import__(&quot;sys&quot;).argv&#39;</span><span class="p">]:</span>
304        <span class="k">try</span><span class="p">:</span>
305            <span class="n">p6</span> <span class="o">=</span> <span class="n">Parameter</span><span class="p">(</span><span class="s">&#39;broken&#39;</span><span class="p">,</span><span class="n">expression</span><span class="o">=</span><span class="n">expr</span><span class="p">)</span>
306            <span class="n">fn</span> <span class="o">=</span> <span class="n">build_eval</span><span class="p">([</span><span class="n">p6</span><span class="p">])</span>
307            <span class="n">fn</span><span class="p">()</span>
308        <span class="k">except</span> <span class="ne">Exception</span><span class="p">,</span><span class="n">msg</span><span class="p">:</span> <span class="k">pass</span>
309        <span class="k">else</span><span class="p">:</span>  <span class="k">raise</span> <span class="s">&quot;Failed to raise error for </span><span class="si">%s</span><span class="s">&quot;</span><span class="o">%</span><span class="n">expr</span>
310</div>
311<span class="k">if</span> <span class="n">__name__</span> <span class="o">==</span> <span class="s">&quot;__main__&quot;</span><span class="p">:</span> <span class="n">test</span><span class="p">()</span>
312</pre></div>
313
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344             >modules</a> |</li>
345        <li><a href="../../index.html">SasView 3.0.0 documentation</a> &raquo;</li>
346          <li><a href="../index.html" >Module code</a> &raquo;</li> 
347      </ul>
348    </div>
349    <div class="footer">
350        &copy; Copyright 2013, The SasView Project.
351      Created using <a href="http://sphinx-doc.org/">Sphinx</a> 1.2.3.
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353  </body>
354</html>
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