As we discussed in class, a common analytical optimization technique is the first derivative test. In this test, you take the first derivative of a function and solve for its zeroes. Because of the way slope works, we know then that these points will be either a minimum or a maximum.
1. Are these points global or local minima/maximaFirst Derivative provides us LOCAL minimum or maximum values
2. Apply the First Derivative test to the function. How many minima/maxima does this function have? Can you identify which zeroes are a minimum and which are a maximum without graphing the function?Answer:
Let's set f'(x)=0, then we have sin(x)=0.3. Therefore, there are infinite many minima/maxima for this function. Since Sin(x) is an alternating function, therefore x=17.5+2nPi are local Max, and x=17.5+ (2n+1)Pi is local Min, where n is in Z.
3. Apply the fsolve() function, as discussed in class, to write a simple program to find minima and maxima for the above function.from scipy.optimize import fsolveimport mathimport numpy as npdef system(coeff):
b0= coeff
f0=3-10*math.sin(math.radians(b0)) return(f0)
b_guess=(0)
b0=fsolve(system,b_guess)
print("Beta0= {}".format(b0))Beta0= [ 17.45760312]
Part 21. Least-Squares RegressionUsing the least-squares regression module discussed in class, perform a regression analysis upon the data provided in the assignment_6.csv file on Moodle. Split the data provided into training and testing data. Use whatever means you like to determine the appropriate form of the model, , to use.
from scipy.optimize import leastsqimport pandas as pdimport matplotlib.pyplot as plt#Read in the datadata=pd.read_csv("C:/Users/fatan/Downloads/assignment6.csv",names=["X","Y"])
#Show Data structureprint(data[0:10])#Split Training set and testing set #Traning set should be around 70% to 80%train=data[0:78]
test=data[79:100]def residual(b,x,y):
return b[1]*x + b[0]-y
b_guess=[0,0]
line= 12.465*train.X -1.53#calculate the optimized parameters for training setb,_ =leastsq(residual,b_guess,args=(test.X, test.Y))
print(b,_)#data visulizationplt.scatter(test.X, test.Y)
plt.plot(train.X, line,"r", label= "Training Set Linear Reg Line")
plt.xlabel("Test Set X value")
plt.ylabel("Test Set Y value")
plt.title("Linear Model Example")
plt.legend()
plt.show()X Y
0 0.916092 10.973234
1 4.610461 63.649082
2 0.164516 8.143623
3 1.089609 13.759627
4 1.589659 15.190665
5 2.264226 23.217127
6 2.656766 27.918476
7 2.665267 28.458073
8 4.358936 56.519672
9 2.882788 26.703205
[ -0.83044318 12.66276417]
image.png
Part 3¶Naive Bayes Classifier¶In Python, implement a Naïve Bayes Classifier, as discussed in class.
from sklearn.naive_bayes import GaussianNB x= np.array([[-3,7],[1,8], [1,1], [-1,0], [2,3], [-4,4], [-2,3], [1,2], [-1,4], [3,6], [-3,0], [-2,5]]) Y = np.array(["Y", "N", "Y", "Y", "Y", "N", "N", "Y", "Y", "Y", "N", "N"]) model = GaussianNB() model.fit(x, Y) predicted= model.predict([[1,1]]) print (predicted)
['Y']
作者：乌然娅措
链接：https://www.jianshu.com/p/a20ccd3d47b0
