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<pre><font face="Courier New"><font color="#008000">#!/usr/bin/env python
</font><font color="#004080">"""Simple examples of weave use.

Code meant to be used for learning/testing, not production.

Fernando Perez &lt;fperez@colorado.edu&gt;

March 2002, updated 2005."""</font>

<font color="#C00000">from</font> <font color="#000000">weave</font> <font color="#C00000">import</font> <font color="#000000">inline</font><font color="#0000C0">,</font><font color="#000000">converters</font>

<font color="#C00000">from</font> <font color="#000000">Numeric</font> <font color="#C00000">import</font> <font color="#0000C0">*</font>

<font color="#008000">#-----------------------------------------------------------------------------
</font><font color="#C00000">def</font> <font color="#000000">simple_print</font><font color="#0000C0">(</font><font color="#000000">input</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"""Simple print test.

    Since there's a hard-coded printf %i in here, it will only work for numerical
    inputs (ints).  """</font>

    <font color="#008000"># note in the printf that newlines must be passed as \\n:
</font>    <font color="#000000">code</font> <font color="#0000C0">=</font> <font color="#004080">'''
    std::cout &lt;&lt; "Printing from C++ (using std::cout) : "&lt;&lt;input&lt;&lt;std::endl;
    '''</font>
    <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'input'</font><font color="#0000C0">]</font><font color="#0000C0">,</font>
           <font color="#000000">verbose</font><font color="#0000C0">=</font><font color="#0080C0">2</font><font color="#0000C0">)</font>  <font color="#008000"># see inline docstring for details</font>

<font color="#C00000">def</font> <font color="#000000">py_print</font><font color="#0000C0">(</font><font color="#000000">input</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"Trivial printer, for timing."</font>
    <font color="#C00000">print</font> <font color="#004080">"Input:"</font><font color="#0000C0">,</font><font color="#000000">input</font>

<font color="#C00000">def</font> <font color="#000000">c_print</font><font color="#0000C0">(</font><font color="#000000">input</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"Trivial printer, for timing."</font>
    <font color="#000000">code</font> <font color="#0000C0">=</font> <font color="#004080">"""printf("Input: %i \\n",input);"""</font>
    <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'input'</font><font color="#0000C0">]</font><font color="#0000C0">)</font>

<font color="#C00000">def</font> <font color="#000000">cpp_print</font><font color="#0000C0">(</font><font color="#000000">input</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"Trivial printer, for timing."</font>
    <font color="#000000">code</font> <font color="#0000C0">=</font> <font color="#004080">"""std::cout &lt;&lt; "Input: " &lt;&lt; input &lt;&lt; std::endl;"""</font>
    <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'input'</font><font color="#0000C0">]</font><font color="#0000C0">)</font>

<font color="#008000">#-----------------------------------------------------------------------------
</font><font color="#008000"># Returning a scalar quantity computed from a Numeric array.
</font><font color="#C00000">def</font> <font color="#000000">trace</font><font color="#0000C0">(</font><font color="#000000">mat</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"""Return the trace of a matrix.
    """</font>
    <font color="#000000">nrow</font><font color="#0000C0">,</font><font color="#000000">ncol</font> <font color="#0000C0">=</font> <font color="#000000">mat</font><font color="#0000C0">.</font><font color="#000000">shape</font>
    <font color="#000000">code</font> <font color="#0000C0">=</font> \
<font color="#004080">""" 
double tr=0.0;

for(int i=0;i&lt;nrow;++i)
    tr += mat(i,i);
return_val = tr;
"""</font>
    <font color="#C00000">return</font> <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'mat'</font><font color="#0000C0">,</font><font color="#004080">'nrow'</font><font color="#0000C0">,</font><font color="#004080">'ncol'</font><font color="#0000C0">]</font><font color="#0000C0">,</font>
                  <font color="#000000">type_converters</font> <font color="#0000C0">=</font> <font color="#000000">converters</font><font color="#0000C0">.</font><font color="#000000">blitz</font><font color="#0000C0">)</font>

<font color="#008000">#-----------------------------------------------------------------------------
</font><font color="#008000"># WRONG CODE: trace() version which modifies in-place a python scalar
</font><font color="#008000"># variable.  Note that this doesn't work, similarly to how in-place changes in
</font><font color="#008000"># python only work for mutable objects. Below is an example that does work.
</font><font color="#C00000">def</font> <font color="#000000">trace2</font><font color="#0000C0">(</font><font color="#000000">mat</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"""Return the trace of a matrix. WRONG CODE.
    """</font>
    <font color="#000000">nrow</font><font color="#0000C0">,</font><font color="#000000">ncol</font> <font color="#0000C0">=</font> <font color="#000000">mat</font><font color="#0000C0">.</font><font color="#000000">shape</font>
    <font color="#000000">tr</font> <font color="#0000C0">=</font> <font color="#0080C0">0.0</font>
    <font color="#000000">code</font> <font color="#0000C0">=</font> \
<font color="#004080">""" 
for(int i=0;i&lt;nrow;++i)
    tr += mat(i,i);
"""</font>
    <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'mat'</font><font color="#0000C0">,</font><font color="#004080">'nrow'</font><font color="#0000C0">,</font><font color="#004080">'ncol'</font><font color="#0000C0">,</font><font color="#004080">'tr'</font><font color="#0000C0">]</font><font color="#0000C0">,</font>
           <font color="#000000">type_converters</font> <font color="#0000C0">=</font> <font color="#000000">converters</font><font color="#0000C0">.</font><font color="#000000">blitz</font><font color="#0000C0">)</font>
    <font color="#C00000">return</font> <font color="#000000">tr</font>

<font color="#008000">#-----------------------------------------------------------------------------
</font><font color="#008000"># Operating in-place in an existing Numeric array. Contrary to trying to modify
</font><font color="#008000"># in-place a scalar, this works correctly.
</font><font color="#C00000">def</font> <font color="#000000">in_place_mult</font><font color="#0000C0">(</font><font color="#000000">num</font><font color="#0000C0">,</font><font color="#000000">mat</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"""In-place multiplication of a matrix by a scalar.
    """</font>
    <font color="#000000">nrow</font><font color="#0000C0">,</font><font color="#000000">ncol</font> <font color="#0000C0">=</font> <font color="#000000">mat</font><font color="#0000C0">.</font><font color="#000000">shape</font>
    <font color="#000000">code</font> <font color="#0000C0">=</font> \
<font color="#004080">"""
for(int i=0;i&lt;nrow;++i)
    for(int j=0;j&lt;ncol;++j)
        mat(i,j) *= num;

"""</font>
    <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'num'</font><font color="#0000C0">,</font><font color="#004080">'mat'</font><font color="#0000C0">,</font><font color="#004080">'nrow'</font><font color="#0000C0">,</font><font color="#004080">'ncol'</font><font color="#0000C0">]</font><font color="#0000C0">,</font>
           <font color="#000000">type_converters</font> <font color="#0000C0">=</font> <font color="#000000">converters</font><font color="#0000C0">.</font><font color="#000000">blitz</font><font color="#0000C0">)</font>

<font color="#008000">#-----------------------------------------------------------------------------
</font><font color="#008000"># Pure Python version for checking.
</font><font color="#C00000">def</font> <font color="#000000">cross_product</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">,</font><font color="#000000">b</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"""Cross product of two 3-d vectors.
    """</font>
    <font color="#000000">cross</font> <font color="#0000C0">=</font> <font color="#0000C0">[</font><font color="#0080C0">0</font><font color="#0000C0">]</font><font color="#0000C0">*</font><font color="#0080C0">3</font>
    <font color="#000000">cross</font><font color="#0000C0">[</font><font color="#0080C0">0</font><font color="#0000C0">]</font> <font color="#0000C0">=</font> <font color="#000000">a</font><font color="#0000C0">[</font><font color="#0080C0">1</font><font color="#0000C0">]</font><font color="#0000C0">*</font><font color="#000000">b</font><font color="#0000C0">[</font><font color="#0080C0">2</font><font color="#0000C0">]</font><font color="#0000C0">-</font><font color="#000000">a</font><font color="#0000C0">[</font><font color="#0080C0">2</font><font color="#0000C0">]</font><font color="#0000C0">*</font><font color="#000000">b</font><font color="#0000C0">[</font><font color="#0080C0">1</font><font color="#0000C0">]</font>
    <font color="#000000">cross</font><font color="#0000C0">[</font><font color="#0080C0">1</font><font color="#0000C0">]</font> <font color="#0000C0">=</font> <font color="#000000">a</font><font color="#0000C0">[</font><font color="#0080C0">2</font><font color="#0000C0">]</font><font color="#0000C0">*</font><font color="#000000">b</font><font color="#0000C0">[</font><font color="#0080C0">0</font><font color="#0000C0">]</font><font color="#0000C0">-</font><font color="#000000">a</font><font color="#0000C0">[</font><font color="#0080C0">0</font><font color="#0000C0">]</font><font color="#0000C0">*</font><font color="#000000">b</font><font color="#0000C0">[</font><font color="#0080C0">2</font><font color="#0000C0">]</font>
    <font color="#000000">cross</font><font color="#0000C0">[</font><font color="#0080C0">2</font><font color="#0000C0">]</font> <font color="#0000C0">=</font> <font color="#000000">a</font><font color="#0000C0">[</font><font color="#0080C0">0</font><font color="#0000C0">]</font><font color="#0000C0">*</font><font color="#000000">b</font><font color="#0000C0">[</font><font color="#0080C0">1</font><font color="#0000C0">]</font><font color="#0000C0">-</font><font color="#000000">a</font><font color="#0000C0">[</font><font color="#0080C0">1</font><font color="#0000C0">]</font><font color="#0000C0">*</font><font color="#000000">b</font><font color="#0000C0">[</font><font color="#0080C0">0</font><font color="#0000C0">]</font>
    <font color="#C00000">return</font> <font color="#000000">array</font><font color="#0000C0">(</font><font color="#000000">cross</font><font color="#0000C0">)</font>

<font color="#008000">#-----------------------------------------------------------------------------
</font><font color="#008000"># Here we return a list from the C code. This is probably *much* slower than
</font><font color="#008000"># the python version, it's meant as an illustration and not as production
</font><font color="#008000"># code.
</font><font color="#C00000">def</font> <font color="#000000">cross_productC</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">,</font><font color="#000000">b</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"""Cross product of two 3-d vectors.
    """</font>
    <font color="#008000"># py::tuple or py::list both work equally well in this case.
</font>    <font color="#000000">code</font> <font color="#0000C0">=</font> \
<font color="#004080">"""
py::tuple cross(3);

cross[0] = a(1)*b(2)-a(2)*b(1);
cross[1] = a(2)*b(0)-a(0)*b(2);
cross[2] = a(0)*b(1)-a(1)*b(0);
return_val = cross;
"""</font>
    <font color="#C00000">return</font> <font color="#000000">array</font><font color="#0000C0">(</font><font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'a'</font><font color="#0000C0">,</font><font color="#004080">'b'</font><font color="#0000C0">]</font><font color="#0000C0">,</font>
                        <font color="#000000">type_converters</font> <font color="#0000C0">=</font> <font color="#000000">converters</font><font color="#0000C0">.</font><font color="#000000">blitz</font><font color="#0000C0">)</font><font color="#0000C0">)</font>

<font color="#008000">#-----------------------------------------------------------------------------
</font><font color="#008000"># C version which accesses a pre-allocated NumPy vector.  Note: when using
</font><font color="#008000"># blitz, index access is done with (,,), not [][][]. In fact, [] indexing
</font><font color="#008000"># fails silently. See this and the next version for a comparison.
</font><font color="#C00000">def</font> <font color="#000000">cross_productC2</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">,</font><font color="#000000">b</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"""Cross product of two 3-d vectors.
    """</font>

    <font color="#000000">cross</font> <font color="#0000C0">=</font> <font color="#000000">zeros</font><font color="#0000C0">(</font><font color="#0080C0">3</font><font color="#0000C0">,</font><font color="#000000">a</font><font color="#0000C0">.</font><font color="#000000">typecode</font><font color="#0000C0">(</font><font color="#0000C0">)</font><font color="#0000C0">)</font>
    <font color="#000000">code</font> <font color="#0000C0">=</font> \
<font color="#004080">"""
cross(0) = a(1)*b(2)-a(2)*b(1);
cross(1) = a(2)*b(0)-a(0)*b(2);
cross(2) = a(0)*b(1)-a(1)*b(0);
"""</font>
    <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'a'</font><font color="#0000C0">,</font><font color="#004080">'b'</font><font color="#0000C0">,</font><font color="#004080">'cross'</font><font color="#0000C0">]</font><font color="#0000C0">,</font>
           <font color="#000000">type_converters</font> <font color="#0000C0">=</font> <font color="#000000">converters</font><font color="#0000C0">.</font><font color="#000000">blitz</font><font color="#0000C0">)</font>
    <font color="#C00000">return</font> <font color="#000000">cross</font>

<font color="#008000">#-----------------------------------------------------------------------------
</font><font color="#008000"># Just like the previous case, but now we don't use the blitz converters.
</font><font color="#008000"># Weave automagically does the type conversions for us.
</font><font color="#C00000">def</font> <font color="#000000">cross_productC3</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">,</font><font color="#000000">b</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"""Cross product of two 3-d vectors.
    """</font>

    <font color="#000000">cross</font> <font color="#0000C0">=</font> <font color="#000000">zeros</font><font color="#0000C0">(</font><font color="#0080C0">3</font><font color="#0000C0">,</font><font color="#000000">a</font><font color="#0000C0">.</font><font color="#000000">typecode</font><font color="#0000C0">(</font><font color="#0000C0">)</font><font color="#0000C0">)</font>
    <font color="#000000">code</font> <font color="#0000C0">=</font> \
<font color="#004080">""" 
cross[0] = a[1]*b[2]-a[2]*b[1];
cross[1] = a[2]*b[0]-a[0]*b[2];
cross[2] = a[0]*b[1]-a[1]*b[0];
"""</font>
    <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'a'</font><font color="#0000C0">,</font><font color="#004080">'b'</font><font color="#0000C0">,</font><font color="#004080">'cross'</font><font color="#0000C0">]</font><font color="#0000C0">)</font>

    <font color="#C00000">return</font> <font color="#000000">cross</font>

<font color="#008000">#-----------------------------------------------------------------------------
</font><font color="#C00000">def</font> <font color="#000000">dot_product</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">,</font><font color="#000000">b</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"""Dot product of two vectors.

    Implemented in a funny (ridiculous) way to use support_code.

    I want to see if we can call another function from inside our own
    code. This would give us a crude way to implement better modularity by
    having global constants which include the raw code for whatever C
    functions we need to call in various places. These can then be included
    via support_code.

    The overhead is that the support code gets compiled in *every* dynamically
    generated module, but I'm not sure that's a big deal since the big
    compilation overhead seems to come from all the fancy C++ templating and
    whatnot.

    Later: ask Eric if there's a cleaner way to do this."""</font>

    <font color="#000000">N</font> <font color="#0000C0">=</font> <font color="#000000">len</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">)</font>
    <font color="#000000">support</font> <font color="#0000C0">=</font> \
<font color="#004080">"""
double mult(double x,double y) {
    return x*y;
}
"""</font>
    <font color="#000000">code</font> <font color="#0000C0">=</font> \
<font color="#004080">"""
double sum = 0.0;
for (int i=0;i&lt;N;++i) {
    sum += mult(a(i),b(i));
}
return_val = sum;
"""</font>
    <font color="#C00000">return</font> <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'a'</font><font color="#0000C0">,</font><font color="#004080">'b'</font><font color="#0000C0">,</font><font color="#004080">'N'</font><font color="#0000C0">]</font><font color="#0000C0">,</font>
                  <font color="#000000">type_converters</font> <font color="#0000C0">=</font> <font color="#000000">converters</font><font color="#0000C0">.</font><font color="#000000">blitz</font><font color="#0000C0">,</font>
                  <font color="#000000">support_code</font> <font color="#0000C0">=</font> <font color="#000000">support</font><font color="#0000C0">,</font>
                  <font color="#000000">libraries</font> <font color="#0000C0">=</font> <font color="#0000C0">[</font><font color="#004080">'m'</font><font color="#0000C0">]</font><font color="#0000C0">,</font>
                  <font color="#0000C0">)</font>

<font color="#008000">#-----------------------------------------------------------------------------
</font><font color="#C00000">def</font> <font color="#000000">sumC</font><font color="#0000C0">(</font><font color="#000000">x</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"""Return the sum of the elements of a 1-d array.
    
    An example of how weave accesses a Numeric array without blitz.  """</font>

    <font color="#000000">num_types</font> <font color="#0000C0">=</font> <font color="#0000C0">{</font><font color="#000000">Float</font><font color="#0000C0">:</font><font color="#004080">'double'</font><font color="#0000C0">,</font>
                 <font color="#000000">Float32</font><font color="#0000C0">:</font><font color="#004080">'float'</font><font color="#0000C0">}</font>
    <font color="#000000">x_type</font> <font color="#0000C0">=</font> <font color="#000000">num_types</font><font color="#0000C0">[</font><font color="#000000">x</font><font color="#0000C0">.</font><font color="#000000">typecode</font><font color="#0000C0">(</font><font color="#0000C0">)</font><font color="#0000C0">]</font>

    <font color="#000000">code</font> <font color="#0000C0">=</font> <font color="#004080">"""
           double result=0.0;
           double element;

           for (int i = 0; i &lt; Nx[0]; i++){

               // Note the type of the pointer below is computed in python
               //element = *(%s *)(x-&gt;data+i*x-&gt;strides[0]);

               // Weave's magic does the above for us:
               element = x[i];
               
               result += element;
               std::cout &lt;&lt; "Element " &lt;&lt; i &lt;&lt; " = " &lt;&lt; element &lt;&lt; "\\n";
           }
           std::cout &lt;&lt; "size x " &lt;&lt; Nx[0] &lt;&lt; "\\n";

           return_val = result;
           """</font> <font color="#0000C0">%</font> <font color="#000000">x_type</font><font color="#0000C0">;</font>

    <font color="#C00000">return</font> <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'x'</font><font color="#0000C0">]</font><font color="#0000C0">,</font><font color="#000000">verbose</font><font color="#0000C0">=</font><font color="#0080C0">0</font><font color="#0000C0">)</font>

<font color="#008000">#-----------------------------------------------------------------------------
</font><font color="#C00000">def</font> <font color="#000000">Cglobals</font><font color="#0000C0">(</font><font color="#000000">arr</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"""How to pass data from function to function via globals.

    This allows the kind of 'over the head' parameter passing via globals
    which is ugly but necessary for using things like generic integrators in
    Numerical Recipes with aditional parameters.  """</font>

    <font color="#000000">support</font> <font color="#0000C0">=</font> \
<font color="#004080">"""
// Declare globals here

/* These blitz guys must be accessed via pointers to avoid a costly copy.
Note that now the type is hardwired in. All python polymorphism is gone.  I
should look into whether this can be fixed by properly using blitz templating.
*/
blitz::Array&lt;int, 1&gt; *G_arr_pt;

// The global M will be visible in the "code" segment
int M = 99;

void aprint(int N) {
  std::cout &lt;&lt; "In aprint()\\n";
  for (int i=0;i&lt;N;++i)
    std::cout &lt;&lt; "arr[" &lt;&lt; i &lt;&lt; "]=" &lt;&lt; (*G_arr_pt)(i) &lt;&lt; " ";
  std::cout &lt;&lt; std::endl;
}

"""</font>
    <font color="#000000">code</font> <font color="#0000C0">=</font> \
<font color="#004080">"""
// Get the passed array reference so the data becomes global
G_arr_pt = &amp;arr;

std::cout &lt;&lt; "global M=" &lt;&lt; M &lt;&lt; std::endl;
std::cout &lt;&lt; "local N=" &lt;&lt; N &lt;&lt; std::endl;


std::cout &lt;&lt; "First, print using the blitz internal printer:\\n";
std::cout &lt;&lt; "all arr\\n";
std::cout &lt;&lt; arr &lt;&lt; std::endl;

std::cout &lt;&lt; "all G_arr\\n";
std::cout &lt;&lt; *G_arr_pt &lt;&lt; std::endl;

std::cout &lt;&lt; "now by loop\\n";

for (int i=0;i&lt;N;++i)
  std::cout &lt;&lt; "arr[" &lt;&lt; i &lt;&lt; "]=" &lt;&lt; arr(i) &lt;&lt; " ";
std::cout &lt;&lt; std::endl;


std::cout &lt;&lt; "Now calling aprint\\n";

aprint(N);
"""</font>
    <font color="#000000">N</font> <font color="#0000C0">=</font> <font color="#000000">len</font><font color="#0000C0">(</font><font color="#000000">arr</font><font color="#0000C0">)</font>
    <font color="#C00000">return</font> <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'arr'</font><font color="#0000C0">,</font><font color="#004080">'N'</font><font color="#0000C0">]</font><font color="#0000C0">,</font>
                  <font color="#000000">type_converters</font> <font color="#0000C0">=</font> <font color="#000000">converters</font><font color="#0000C0">.</font><font color="#000000">blitz</font><font color="#0000C0">,</font>
                  <font color="#000000">support_code</font> <font color="#0000C0">=</font> <font color="#000000">support</font><font color="#0000C0">,</font>
                  <font color="#000000">libraries</font> <font color="#0000C0">=</font> <font color="#0000C0">[</font><font color="#004080">'m'</font><font color="#0000C0">]</font><font color="#0000C0">,</font>
                  <font color="#000000">verbose</font> <font color="#0000C0">=</font> <font color="#0080C0">0</font><font color="#0000C0">,</font>
                  <font color="#0000C0">)</font>


<font color="#008000">#-----------------------------------------------------------------------------
</font><font color="#008000"># Two trivial examples using the C math library follow.
</font><font color="#C00000">def</font> <font color="#000000">powC</font><font color="#0000C0">(</font><font color="#000000">x</font><font color="#0000C0">,</font><font color="#000000">n</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"""powC(x,n) -&gt; x**n. Implemented using the C pow() function.
    """</font>
    <font color="#000000">support</font> <font color="#0000C0">=</font> \
<font color="#004080">"""
#include &lt;math.h&gt;
"""</font>
    <font color="#000000">code</font> <font color="#0000C0">=</font> \
<font color="#004080">"""
return_val = pow(x,n);
"""</font>
    <font color="#C00000">return</font> <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'x'</font><font color="#0000C0">,</font><font color="#004080">'n'</font><font color="#0000C0">]</font><font color="#0000C0">,</font>
                  <font color="#000000">type_converters</font> <font color="#0000C0">=</font> <font color="#000000">converters</font><font color="#0000C0">.</font><font color="#000000">blitz</font><font color="#0000C0">,</font>
                  <font color="#000000">support_code</font> <font color="#0000C0">=</font> <font color="#000000">support</font><font color="#0000C0">,</font>
                  <font color="#000000">libraries</font> <font color="#0000C0">=</font> <font color="#0000C0">[</font><font color="#004080">'m'</font><font color="#0000C0">]</font><font color="#0000C0">,</font>
                  <font color="#0000C0">)</font>

<font color="#008000"># Some callback examples
</font><font color="#C00000">def</font> <font color="#000000">foo</font><font color="#0000C0">(</font><font color="#000000">x</font><font color="#0000C0">,</font><font color="#000000">y</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
     <font color="#C00000">print</font> <font color="#004080">"In Python's foo:"</font>
     <font color="#C00000">print</font> <font color="#004080">'x'</font><font color="#0000C0">,</font><font color="#000000">x</font>
     <font color="#C00000">print</font> <font color="#004080">'y'</font><font color="#0000C0">,</font><font color="#000000">y</font>
     <font color="#C00000">return</font> <font color="#000000">x</font>

<font color="#C00000">def</font> <font color="#000000">cfoo</font><font color="#0000C0">(</font><font color="#000000">x</font><font color="#0000C0">,</font><font color="#000000">y</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
      <font color="#000000">code</font> <font color="#0000C0">=</font> <font color="#004080">"""
      printf("Attemtping to call back foo() from C...\\n");
      py::tuple foo_args(2);
      py::object z;  // This will hold the return value of foo()
      foo_args[0] = x;
      foo_args[1] = y;
      z = foo.call(foo_args);
      printf("Exiting C code.\\n");
      return_val = z;
      """</font>
      <font color="#C00000">return</font> <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#004080">"foo x y"</font><font color="#0000C0">.</font><font color="#000000">split</font><font color="#0000C0">(</font><font color="#0000C0">)</font> <font color="#0000C0">)</font>

<font color="#000000">x</font><font color="#0000C0">=</font><font color="#0080C0">99</font>
<font color="#000000">y</font><font color="#0000C0">=</font><font color="#004080">"Hello"</font>

<font color="#C00000">print</font> <font color="#004080">"Pure python..."</font>
<font color="#000000">z</font><font color="#0000C0">=</font><font color="#000000">foo</font><font color="#0000C0">(</font><font color="#000000">x</font><font color="#0000C0">,</font><font color="#000000">y</font><font color="#0000C0">)</font>
<font color="#C00000">print</font> <font color="#004080">"foo returned:"</font><font color="#0000C0">,</font><font color="#000000">z</font>
<font color="#C00000">print</font> <font color="#004080">"\nVia weave..."</font>
<font color="#000000">z</font><font color="#0000C0">=</font><font color="#000000">cfoo</font><font color="#0000C0">(</font><font color="#000000">x</font><font color="#0000C0">,</font><font color="#000000">y</font><font color="#0000C0">)</font>
<font color="#C00000">print</font> <font color="#004080">"cfoo returned:"</font><font color="#0000C0">,</font><font color="#000000">z</font>

<font color="#008000"># Complex numbers
</font><font color="#C00000">def</font> <font color="#000000">complex_test</font><font color="#0000C0">(</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#000000">a</font> <font color="#0000C0">=</font> <font color="#000000">zeros</font><font color="#0000C0">(</font><font color="#0000C0">(</font><font color="#0080C0">4</font><font color="#0000C0">,</font><font color="#0080C0">4</font><font color="#0000C0">)</font><font color="#0000C0">,</font><font color="#000000">Complex</font><font color="#0000C0">)</font>
    <font color="#000000">a</font><font color="#0000C0">[</font><font color="#0080C0">0</font><font color="#0000C0">,</font><font color="#0080C0">0</font><font color="#0000C0">]</font> <font color="#0000C0">=</font> <font color="#0080C0">1</font><font color="#0000C0">+</font><font color="#0080C0">2j</font>
    <font color="#000000">a</font><font color="#0000C0">[</font><font color="#0080C0">1</font><font color="#0000C0">,</font><font color="#0080C0">1</font><font color="#0000C0">]</font> <font color="#0000C0">=</font> <font color="#0080C0">2</font><font color="#0000C0">+</font><font color="#0080C0">3.5j</font>
    <font color="#C00000">print</font> <font color="#004080">'Before\n'</font><font color="#0000C0">,</font><font color="#000000">a</font>
    <font color="#000000">code</font> <font color="#0000C0">=</font> \
<font color="#004080">"""
std::complex&lt;double&gt; i(0, 1);
std::cout &lt;&lt; a(1,1) &lt;&lt; std::endl;
a(2,2) = 3.0+4.5*i;
//a(2,2).imag = 4.5;
"""</font>
    <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'a'</font><font color="#0000C0">]</font><font color="#0000C0">,</font><font color="#000000">type_converters</font> <font color="#0000C0">=</font> <font color="#000000">converters</font><font color="#0000C0">.</font><font color="#000000">blitz</font><font color="#0000C0">)</font>
    <font color="#C00000">print</font> <font color="#004080">'After\n'</font><font color="#0000C0">,</font><font color="#000000">a</font>

<font color="#000000">complex_test</font><font color="#0000C0">(</font><font color="#0000C0">)</font>

<font color="#008000">#-----------------------------------------------------------------------------
</font><font color="#C00000">def</font> <font color="#000000">sinC</font><font color="#0000C0">(</font><font color="#000000">x</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#004080">"""sinC(x) -&gt; sin(x). Implemented using the C sin() function.
    """</font>
    <font color="#000000">support</font> <font color="#0000C0">=</font> \
<font color="#004080">"""
#include &lt;math.h&gt;
"""</font>
    <font color="#000000">code</font> <font color="#0000C0">=</font> \
<font color="#004080">"""
return_val = sin(x);
"""</font>
    <font color="#C00000">return</font> <font color="#000000">inline</font><font color="#0000C0">(</font><font color="#000000">code</font><font color="#0000C0">,</font><font color="#0000C0">[</font><font color="#004080">'x'</font><font color="#0000C0">]</font><font color="#0000C0">,</font>
                  <font color="#000000">type_converters</font> <font color="#0000C0">=</font> <font color="#000000">converters</font><font color="#0000C0">.</font><font color="#000000">blitz</font><font color="#0000C0">,</font>
                  <font color="#000000">support_code</font> <font color="#0000C0">=</font> <font color="#000000">support</font><font color="#0000C0">,</font>
                  <font color="#000000">libraries</font> <font color="#0000C0">=</font> <font color="#0000C0">[</font><font color="#004080">'m'</font><font color="#0000C0">]</font><font color="#0000C0">,</font>
                  <font color="#0000C0">)</font>

<font color="#C00000">def</font> <font color="#000000">in_place_multNum</font><font color="#0000C0">(</font><font color="#000000">num</font><font color="#0000C0">,</font><font color="#000000">mat</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#000000">mat</font> <font color="#0000C0">*=</font> <font color="#000000">num</font>

<font color="#C00000">def</font> <font color="#000000">main</font><font color="#0000C0">(</font><font color="#0000C0">)</font><font color="#0000C0">:</font>
    <font color="#C00000">print</font> <font color="#004080">'Printing:'</font>
    <font color="#C00000">print</font> <font color="#004080">'\nPassing an int:'</font>
    <font color="#000000">simple_print</font><font color="#0000C0">(</font><font color="#0080C0">42</font><font color="#0000C0">)</font>
    <font color="#C00000">print</font> <font color="#004080">'\nNow passing a float.'</font>
    <font color="#000000">simple_print</font><font color="#0000C0">(</font><font color="#0080C0">42.1</font><font color="#0000C0">)</font>
    <font color="#C00000">print</font> <font color="#004080">'\nAnd a string.'</font>
    <font color="#000000">simple_print</font><font color="#0000C0">(</font><font color="#004080">'Hello World!'</font><font color="#0000C0">)</font>

    <font color="#000000">A</font> <font color="#0000C0">=</font> <font color="#000000">zeros</font><font color="#0000C0">(</font><font color="#0000C0">(</font><font color="#0080C0">3</font><font color="#0000C0">,</font><font color="#0080C0">3</font><font color="#0000C0">)</font><font color="#0000C0">,</font><font color="#004080">'d'</font><font color="#0000C0">)</font>

    <font color="#000000">A</font><font color="#0000C0">[</font><font color="#0080C0">0</font><font color="#0000C0">,</font><font color="#0080C0">0</font><font color="#0000C0">]</font><font color="#0000C0">,</font><font color="#000000">A</font><font color="#0000C0">[</font><font color="#0080C0">1</font><font color="#0000C0">,</font><font color="#0080C0">1</font><font color="#0000C0">]</font><font color="#0000C0">,</font><font color="#000000">A</font><font color="#0000C0">[</font><font color="#0080C0">2</font><font color="#0000C0">,</font><font color="#0080C0">2</font><font color="#0000C0">]</font> <font color="#0000C0">=</font> <font color="#0080C0">1</font><font color="#0000C0">,</font><font color="#0080C0">2.5</font><font color="#0000C0">,</font><font color="#0080C0">3.3</font>

    <font color="#C00000">print</font> <font color="#004080">'\nMatrix A:\n'</font><font color="#0000C0">,</font><font color="#000000">A</font>
    <font color="#C00000">print</font> <font color="#004080">'Trace by two methods. Second fails, see code for details.'</font>
    <font color="#C00000">print</font> <font color="#004080">'\ntr(A)='</font><font color="#0000C0">,</font><font color="#000000">trace</font><font color="#0000C0">(</font><font color="#000000">A</font><font color="#0000C0">)</font>
    <font color="#C00000">print</font> <font color="#004080">'\ntr(A)='</font><font color="#0000C0">,</font><font color="#000000">trace2</font><font color="#0000C0">(</font><font color="#000000">A</font><font color="#0000C0">)</font>

    <font color="#000000">a</font> <font color="#0000C0">=</font> <font color="#0080C0">5.6</font>
    <font color="#C00000">print</font> <font color="#004080">'\nMultiplying A in place by %s:'</font> <font color="#0000C0">%</font> <font color="#000000">a</font>
    <font color="#000000">in_place_mult</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">,</font><font color="#000000">A</font><font color="#0000C0">)</font>
    <font color="#C00000">print</font> <font color="#000000">A</font>

    <font color="#008000"># now some simple operations with 3-vectors.
</font>    <font color="#000000">a</font> <font color="#0000C0">=</font> <font color="#000000">array</font><font color="#0000C0">(</font><font color="#0000C0">[</font><font color="#0080C0">4.3</font><font color="#0000C0">,</font><font color="#0080C0">1.5</font><font color="#0000C0">,</font><font color="#0080C0">5.6</font><font color="#0000C0">]</font><font color="#0000C0">)</font>
    <font color="#000000">b</font> <font color="#0000C0">=</font> <font color="#000000">array</font><font color="#0000C0">(</font><font color="#0000C0">[</font><font color="#0080C0">0.8</font><font color="#0000C0">,</font><font color="#0080C0">2.9</font><font color="#0000C0">,</font><font color="#0080C0">3.8</font><font color="#0000C0">]</font><font color="#0000C0">)</font>

    <font color="#C00000">print</font> <font color="#004080">'\nPython and C versions follow. Results should be identical:'</font>
    <font color="#C00000">print</font> <font color="#004080">'a ='</font><font color="#0000C0">,</font><font color="#000000">a</font>
    <font color="#C00000">print</font> <font color="#004080">'b ='</font><font color="#0000C0">,</font><font color="#000000">b</font>

    <font color="#C00000">print</font> <font color="#004080">'\nsum(a_i) ='</font><font color="#0000C0">,</font><font color="#000000">sum</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">)</font>
    <font color="#C00000">print</font> <font color="#004080">'sum(a_i) ='</font><font color="#0000C0">,</font><font color="#000000">sumC</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">)</font>

    <font color="#C00000">print</font> <font color="#004080">'\na.b ='</font><font color="#0000C0">,</font><font color="#000000">dot</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">,</font><font color="#000000">b</font><font color="#0000C0">)</font>
    <font color="#C00000">print</font> <font color="#004080">'a.b ='</font><font color="#0000C0">,</font><font color="#000000">dot_product</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">,</font><font color="#000000">b</font><font color="#0000C0">)</font>

    <font color="#C00000">print</font> <font color="#004080">'\na x b ='</font><font color="#0000C0">,</font><font color="#000000">cross_product</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">,</font><font color="#000000">b</font><font color="#0000C0">)</font>
    <font color="#C00000">print</font> <font color="#004080">'a x b ='</font><font color="#0000C0">,</font><font color="#000000">cross_productC</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">,</font><font color="#000000">b</font><font color="#0000C0">)</font>

    <font color="#C00000">print</font> <font color="#004080">'\nIn-place versions.'</font>
    <font color="#C00000">print</font> <font color="#004080">'a x b ='</font><font color="#0000C0">,</font><font color="#000000">cross_productC2</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">,</font><font color="#000000">b</font><font color="#0000C0">)</font>
    <font color="#C00000">print</font> <font color="#004080">'a x b ='</font><font color="#0000C0">,</font><font color="#000000">cross_productC3</font><font color="#0000C0">(</font><font color="#000000">a</font><font color="#0000C0">,</font><font color="#000000">b</font><font color="#0000C0">)</font>

    <font color="#C00000">print</font> <font color="#004080">'\nSimple functions using the C math library:'</font>
    <font color="#C00000">import</font> <font color="#000000">math</font>
    <font color="#000000">x</font> <font color="#0000C0">=</font> <font color="#0080C0">3.5</font>
    <font color="#000000">n</font> <font color="#0000C0">=</font> <font color="#0080C0">4</font>
    <font color="#000000">theta</font> <font color="#0000C0">=</font> <font color="#000000">math</font><font color="#0000C0">.</font><font color="#000000">pi</font><font color="#0000C0">/</font><font color="#0080C0">4.</font>
    <font color="#C00000">print</font> <font color="#004080">'\nx**'</font><font color="#0000C0">+</font><font color="#000000">str</font><font color="#0000C0">(</font><font color="#000000">n</font><font color="#0000C0">)</font><font color="#0000C0">+</font><font color="#004080">'='</font><font color="#0000C0">,</font><font color="#000000">x</font><font color="#0000C0">**</font><font color="#000000">n</font>
    <font color="#C00000">print</font> <font color="#004080">'x**'</font><font color="#0000C0">+</font><font color="#000000">str</font><font color="#0000C0">(</font><font color="#000000">n</font><font color="#0000C0">)</font><font color="#0000C0">+</font><font color="#004080">'='</font><font color="#0000C0">,</font><font color="#000000">powC</font><font color="#0000C0">(</font><font color="#000000">x</font><font color="#0000C0">,</font><font color="#000000">n</font><font color="#0000C0">)</font>
    <font color="#C00000">print</font> <font color="#004080">'\nsin('</font><font color="#0000C0">+</font><font color="#000000">str</font><font color="#0000C0">(</font><font color="#000000">theta</font><font color="#0000C0">)</font><font color="#0000C0">+</font><font color="#004080">')='</font><font color="#0000C0">,</font><font color="#000000">math</font><font color="#0000C0">.</font><font color="#000000">sin</font><font color="#0000C0">(</font><font color="#000000">theta</font><font color="#0000C0">)</font>
    <font color="#C00000">print</font> <font color="#004080">'sin('</font><font color="#0000C0">+</font><font color="#000000">str</font><font color="#0000C0">(</font><font color="#000000">theta</font><font color="#0000C0">)</font><font color="#0000C0">+</font><font color="#004080">')='</font><font color="#0000C0">,</font><font color="#000000">sinC</font><font color="#0000C0">(</font><font color="#000000">theta</font><font color="#0000C0">)</font>

    <font color="#C00000">print</font> <font color="#004080">'\nGlobal variables and explicitly typed blitz arrays.'</font>
    <font color="#000000">x</font> <font color="#0000C0">=</font> <font color="#000000">array</font><font color="#0000C0">(</font><font color="#0000C0">[</font><font color="#0080C0">4</font><font color="#0000C0">,</font><font color="#0080C0">5</font><font color="#0000C0">,</font><font color="#0080C0">6</font><font color="#0000C0">]</font><font color="#0000C0">)</font>
    <font color="#C00000">print</font> <font color="#004080">'x is a Numeric array:\nx='</font><font color="#0000C0">,</font><font color="#000000">x</font>
    <font color="#C00000">print</font> <font color="#004080">'Now using weave:'</font>
    <font color="#000000">Cglobals</font> <font color="#0000C0">(</font><font color="#000000">x</font><font color="#0000C0">)</font>

<font color="#C00000">if</font> <font color="#000000">__name__</font> <font color="#0000C0">==</font> <font color="#004080">'__main__'</font><font color="#0000C0">:</font>
    <font color="#000000">main</font><font color="#0000C0">(</font><font color="#0000C0">)</font><font color="#000000"></font></font></pre>

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