diff -r 884d42eff66d -r 39d7c4e14585 day1/cheatsheet6.tex --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/day1/cheatsheet6.tex Tue Nov 10 14:32:32 2009 +0530 @@ -0,0 +1,44 @@ +\documentclass[12pt]{article} +\title{Solving Equations \& ODEs} +\author{FOSSEE} +\begin{document} +\date{} +\vspace{-1in} +\begin{center} +\LARGE{Solving Equations \& ODEs}\\ +\large{FOSSEE} +\end{center} +\section{Solving linear equations} +\begin{verbatim} + In []: A = array([[3,2,-1], + [2,-2,4], + [-1, 0.5, -1]]) + In []: b = array([[1], [-2], [0]]) + In []: x = solve(A, b) + In []: Ax = dot(A,x) + In []: allclose(Ax, b) + Out[]: True +\end{verbatim} +\section{Finding roots} +\begin{verbatim} + In []: coeffs = [1, 6, 13] + In []: roots(coeffs) +\end{verbatim} +Finding the roots of a function +\begin{verbatim} +In []: fsolve(sin(x)+cos(x)**2, 0) +\end{verbatim} +\section{ODE} +\begin{verbatim} + In []: def epid(y, t): + .... k, L = 0.00003, 25000 + .... return k*y*(L-y) + .... + + In []: t = arange(0, 12, 0.2) + + In []: y = odeint(epid, 250, t) + + In []: plot(t, y) +\end{verbatim} +\end{document}