least_square_fit/questions.rst
changeset 522 d33698326409
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/least_square_fit/questions.rst	Wed Dec 01 16:51:35 2010 +0530
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+Objective Questions
+-------------------
+
+ 1. What does ones_like([1, 2, 3]) produce
+
+   a. array([1, 1, 1])
+   #. [1, 1, 1]
+   #. [1.0, 1.0, 1.0]
+   #. Error
+   
+   Answer: array([1, 1, 1])
+   
+ 2. What does ones_like([1.2, 3, 4, 5]) produce
+
+   a. [1.2, 3, 4, 5]
+   #. array([1.0, 1.0, 1.0, 1.0])
+   #. array([1, 1, 1, 1])
+   #. array([1.2, 3, 4, 5])
+
+   Answer: array([1.0, 1.0, 1.0, 1.0])
+
+ 3. The plot of ``u`` vs ``v`` is a bunch of scattered points that show a
+    linear trend. How do you find the least square fit line of ``u`` vs ``v``.
+
+   Answer::
+
+      A = array(u, ones_like(u)).T
+      result = lstsq(A, v)
+      m, c = result[0]
+
+      lst_line = m * u + c
+