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Added Artisan #3 (solved) and #4 (unsolved)

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Nicolas Rougier 2014-07-20 11:48:36 +02:00
parent 8647fc74fd
commit 5c5f62c582
2 changed files with 50 additions and 0 deletions
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23
README.html
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@ -469,6 +469,29 @@ np.bincount(A) == C ?</p>
<span class="keyword">print</span> <span class="name">np</span><span class="operator">.</span><span class="name">unpackbits</span><span class="punctuation">(</span><span class="name">I</span><span class="punctuation">[:,</span> <span class="name">np</span><span class="operator">.</span><span class="name">newaxis</span><span class="punctuation">],</span> <span class="name">axis</span><span class="operator">=</span><span class="literal number integer">1</span><span class="punctuation">)</span> <span class="keyword">print</span> <span class="name">np</span><span class="operator">.</span><span class="name">unpackbits</span><span class="punctuation">(</span><span class="name">I</span><span class="punctuation">[:,</span> <span class="name">np</span><span class="operator">.</span><span class="name">newaxis</span><span class="punctuation">],</span> <span class="name">axis</span><span class="operator">=</span><span class="literal number integer">1</span><span class="punctuation">)</span>
</pre> </pre>
</li> </li>
<li><p class="first">Consider 2 sets of points P0,P1 describing lines (2d) and a point p, how to
compute distance from p to each line i (P0[i],P1[i]) ?</p>
<pre class="code python literal-block">
<span class="keyword">def</span> <span class="name function">distance</span><span class="punctuation">(</span><span class="name">P0</span><span class="punctuation">,</span> <span class="name">P1</span><span class="punctuation">,</span> <span class="name">p</span><span class="punctuation">):</span>
<span class="name">T</span> <span class="operator">=</span> <span class="name">P1</span> <span class="operator">-</span> <span class="name">P0</span>
<span class="name">L</span> <span class="operator">=</span> <span class="punctuation">(</span><span class="name">T</span><span class="operator">**</span><span class="literal number integer">2</span><span class="punctuation">)</span><span class="operator">.</span><span class="name">sum</span><span class="punctuation">(</span><span class="name">axis</span><span class="operator">=</span><span class="literal number integer">1</span><span class="punctuation">)</span>
<span class="name">U</span> <span class="operator">=</span> <span class="operator">-</span><span class="punctuation">((</span><span class="name">P0</span><span class="punctuation">[:,</span><span class="literal number integer">0</span><span class="punctuation">]</span><span class="operator">-</span><span class="name">p</span><span class="punctuation">[</span><span class="literal number integer">0</span><span class="punctuation">])</span><span class="operator">*</span><span class="name">T</span><span class="punctuation">[:,</span><span class="literal number integer">0</span><span class="punctuation">]</span> <span class="operator">+</span> <span class="punctuation">(</span><span class="name">P0</span><span class="punctuation">[:,</span><span class="literal number integer">1</span><span class="punctuation">]</span><span class="operator">-</span><span class="name">p</span><span class="punctuation">[</span><span class="literal number integer">1</span><span class="punctuation">])</span><span class="operator">*</span><span class="name">T</span><span class="punctuation">[:,</span><span class="literal number integer">1</span><span class="punctuation">])</span> <span class="operator">/</span> <span class="name">L</span>
<span class="name">U</span> <span class="operator">=</span> <span class="name">U</span><span class="operator">.</span><span class="name">reshape</span><span class="punctuation">(</span><span class="name builtin">len</span><span class="punctuation">(</span><span class="name">U</span><span class="punctuation">),</span><span class="literal number integer">1</span><span class="punctuation">)</span>
<span class="name">D</span> <span class="operator">=</span> <span class="name">P0</span> <span class="operator">+</span> <span class="name">U</span><span class="operator">*</span><span class="name">T</span> <span class="operator">-</span> <span class="name">p</span>
<span class="keyword">return</span> <span class="name">np</span><span class="operator">.</span><span class="name">sqrt</span><span class="punctuation">((</span><span class="name">D</span><span class="operator">**</span><span class="literal number integer">2</span><span class="punctuation">)</span><span class="operator">.</span><span class="name">sum</span><span class="punctuation">(</span><span class="name">axis</span><span class="operator">=</span><span class="literal number integer">1</span><span class="punctuation">))</span>
<span class="name">P0</span> <span class="operator">=</span> <span class="name">np</span><span class="operator">.</span><span class="name">random</span><span class="operator">.</span><span class="name">uniform</span><span class="punctuation">(</span><span class="operator">-</span><span class="literal number integer">10</span><span class="punctuation">,</span><span class="literal number integer">10</span><span class="punctuation">,(</span><span class="literal number integer">100</span><span class="punctuation">,</span><span class="literal number integer">2</span><span class="punctuation">))</span>
<span class="name">P1</span> <span class="operator">=</span> <span class="name">np</span><span class="operator">.</span><span class="name">random</span><span class="operator">.</span><span class="name">uniform</span><span class="punctuation">(</span><span class="operator">-</span><span class="literal number integer">10</span><span class="punctuation">,</span><span class="literal number integer">10</span><span class="punctuation">,(</span><span class="literal number integer">100</span><span class="punctuation">,</span><span class="literal number integer">2</span><span class="punctuation">))</span>
<span class="name">p</span> <span class="operator">=</span> <span class="name">np</span><span class="operator">.</span><span class="name">random</span><span class="operator">.</span><span class="name">uniform</span><span class="punctuation">(</span><span class="operator">-</span><span class="literal number integer">10</span><span class="punctuation">,</span><span class="literal number integer">10</span><span class="punctuation">,(</span> <span class="literal number integer">1</span><span class="punctuation">,</span><span class="literal number integer">2</span><span class="punctuation">))</span>
<span class="keyword">print</span> <span class="name">distance</span><span class="punctuation">(</span><span class="name">P0</span><span class="punctuation">,</span> <span class="name">P1</span><span class="punctuation">,</span> <span class="name">p</span><span class="punctuation">)</span>
</pre>
</li>
<li><p class="first">Consider 2 sets of points P0,P1 describing lines (2d) and a set of point P,
how to compute distance from each point j (P[j]) to each line i (P0[i],P1[i]) ?</p>
<pre class="code python literal-block">
<span class="name">Answer</span> <span class="name">needed</span> <span class="name">actually</span>
</pre>
</li>
</ol> </ol>
</div> </div>
<div class="section" id="adept"> <div class="section" id="adept">

27
README.rst
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@ -560,6 +560,33 @@ Artisan
print np.unpackbits(I[:, np.newaxis], axis=1) print np.unpackbits(I[:, np.newaxis], axis=1)
3. Consider 2 sets of points P0,P1 describing lines (2d) and a point p, how to
compute distance from p to each line i (P0[i],P1[i]) ?
.. code-block:: python
def distance(P0, P1, p):
T = P1 - P0
L = (T**2).sum(axis=1)
U = -((P0[:,0]-p[0])*T[:,0] + (P0[:,1]-p[1])*T[:,1]) / L
U = U.reshape(len(U),1)
D = P0 + U*T - p
return np.sqrt((D**2).sum(axis=1))
P0 = np.random.uniform(-10,10,(100,2))
P1 = np.random.uniform(-10,10,(100,2))
p = np.random.uniform(-10,10,( 1,2))
print distance(P0, P1, p)
4. Consider 2 sets of points P0,P1 describing lines (2d) and a set of point P,
how to compute distance from each point j (P[j]) to each line i (P0[i],P1[i]) ?
.. code-block:: python
Answer needed actually
Adept Adept
===== =====