Page - 25 - in Programming for Computations – Python - A Gentle Introduction to Numerical Simulations with Python 3.6, Volume Second Edition

1.6 Plotting,PrintingandInputData 25 t = np.linspace(-2, 2, 100) # choose 100 points in time interval f_values = t**2 g_values = np.exp(t) plt.plot(t, f_values, ’r’, t, g_values, ’b--’) plt.xlabel(’t’) plt.ylabel(’f and g’) plt.legend([’t**2’, ’e**t’]) plt.title(’Plotting of two functions (t**2 and e**t)’) plt.grid(’on’) plt.axis([-3, 3, -1, 10]) plt.show() In thiscode,yourecognizethecommandsexplainedjust above.Their impacton theplotmaybe seen inFig.1.3,which is producedwhen theprogramisexecuted. Fig. 1.3 The functionsf(t)= t2 andg(t)= et Inaddition,yousee how plt.plot(t, f_values, ’r’, t, g_values, ’b--’) causesbothcurves tobe seen in the sameplot.Notice thestructurehere,within the parenthesis, we first describe plotting of the one curve with t, f_values, ’r’, before plotting of the second curve is specified by t, g_values, ’b--’. These two “plot specifications” are separated by a comma. Had there been more curves to plot in the same plot, we would simply extend the list in a similar way. For each curve,colorandlinestyleisspecifiedindependentlyoftheothercurvespecifications in the plot command(no specification givesdefault appearance).Furthermore,you noticehow plt.legend([’t**2’, ’e**t’]) creates the right labelling of the curves. Note that the order of curve specifications in the plot command must be the same as the order of legend specifications in