Question

我试图运行一个项目，但无法运行Java文件Utility.java。无法在以下语句中导入包。

(-1, 1)

由于我在cp中应该包含哪个路径来执行jar文件感到困惑，我尝试使用2条路径命令

# Needs: python -m pip install numpy matplotlib
import math, sys
import numpy as np, matplotlib.pyplot as plt, matplotlib.animation as animation
from matplotlib.animation import FuncAnimation


x_range = (0., math.pi, 0.1) # (xmin, xmax, xstep)
y_range = (-0.2, 1.2) # (ymin, ymax)
num_iterations = 50

def f(x):
    return np.sin(x)

def derr(iteration):
    return 0.7 ** (iteration + 15)
    
    
def MSE(a, b):
    return (np.abs(np.array(a) - np.array(b)) ** 2).mean()

def quadraticRegression(*, x, data, dErr):
    x, data = np.array(x), np.array(data)
    assert x.size == data.size, (x.size, data.size)

    a = 1 #Starting values
    b = 1
    c = 1

    a_momentum = 0.1 #Momentum to counter steady state error
    b_momentum = 0.1
    c_momentum = 0.1

    estimate = a*x**2 + b*x + c #Estimate curve
    error = MSE(data, estimate) #Get errors 'n stuff
    errorOld = 0.

    lr = 10. ** -4 #learning rate
    while abs(error - errorOld) > dErr:
        #Fit a (dE/da)
        deda = np.sum(2*x**2 * (a*x**2 + b*x + c - data))/len(data)
        correction = deda*lr
        a_momentum = (a_momentum)*0.99 + correction*0.1 #0.99 is to slow down momentum when correction speed changes
        a = a - correction - a_momentum
    
        #fit b (dE/db)
        dedb = np.sum(2*x*(a*x**2 + b*x + c - data))/len(data)
        correction = dedb*lr
        b_momentum = (b_momentum)*0.99 + correction*0.1
        b = b - correction - b_momentum

        #fit c (dE/dc)
        dedc = np.sum(2*(a*x**2 + b*x + c - data))/len(data)
        correction = dedc*lr
        c_momentum = (c_momentum)*0.99 + correction*0.1
        c = c - correction - c_momentum

        #Update model and find errors
        estimate = a*x**2 +b*x + c
        errorOld = error
        #print(error)
        error = MSE(data, estimate)

    return a, b, c, error


        
fig, ax = plt.subplots()
fig.set_tight_layout(True)

x = np.arange(x_range[0], x_range[1], x_range[2])
#ax.scatter(x, x + np.random.normal(0, 3.0, len(x)))
line0, line1 = None, None

do_save = len(sys.argv) > 1 and sys.argv[1] == 'save'

def g(x, derr):
    a, b, c, error = quadraticRegression(x = x, data = f(x), dErr = derr)
    return a * x ** 2 + b * x + c
    
def dummy(x):
    return np.ones_like(x, dtype = np.float64) * 100.

def update(i):
    global line0, line1
    
    de = derr(i)
    
    if line0 is None:
        assert line1 is None
        line0, = ax.plot(x, f(x), 'r-', linewidth=2)
        line1, = ax.plot(x, g(x, de), 'r-', linewidth=2, color = 'blue')
        ax.set_ylim(y_range[0], y_range[1])
        
    if do_save:
        sys.stdout.write(str(i) + ' ')
        sys.stdout.flush()

    label = 'iter {0} derr {1}'.format(i, round(de, math.ceil(-math.log(de) / math.log(10)) + 2))
    line1.set_ydata(g(x, de))
    ax.set_xlabel(label)
    return line1, ax

if __name__ == '__main__':
    anim = FuncAnimation(fig, update, frames = np.arange(0, num_iterations), interval = 200)
    if do_save:
        anim.save('line.gif', dpi = 200, writer = 'imagemagick')
    else:
        plt.show()

Here is the screenshot of the folders depicting location of files

Screenshot of commons-math-1.2 folder

根据我的说法，文件位置错误。附言我是Java的初学者。操作系统是ubuntu

Answer 1

按照以下步骤编译和执行独立的Java程序。

我想您将在target-directory = /home/vidhi/Downloads/explorerChain/explorerchain-master处执行代码。

将jar文件commons-math-1.2.jar复制到位置target-directory。

Command : # cp /source-directory/commons-math-1.2.jar target-directory/

下一步转到目标目录。

Command : # cd <target-directory>

下一步编译您的Java文件。：

Command : # javac -cp commons-math-1.2.jar . Utility.java

接下来运行已编译的java文件：

Command : # java Utility

错误：软件包org.apache.commons.math.distribution不存在

1 个答案: