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昨天发布了此版本的早期版本,但我似乎无法将此版本添加到该帖子中,因为似乎有人已关闭该帖子进行编辑,所以这是新帖子中的新版本。

我有下面的脚本,它执行以下操作:
1.) 为 S 形数据绘制最佳拟合曲线。
2.) 根据 x 和 y 的新最大和最小坐标重新调整数据大小。
3.) 为调整大小的数据计算并绘制新的最佳拟合曲线。

第 1 步和第 2 步似乎工作正常,但第 3 步却不行。如果您运行该脚本,您将看到它为调整大小的数据绘制了一条完全无效的曲线。

谁能告诉我如何修改下面的代码,以便它为调整大小的数据创建并绘制真正的最佳拟合 sigmoidal 曲线? 当在可能的最大值和最小值范围内重新调整大小时,这需要可重现。

我似乎能够将问题跟踪到 New_p,它在以下代码行中定义:

New_p, New_cov, New_infodict, New_mesg, New_ier = scipy.optimize.leastsq( 
    residuals,New_p_guess,args=(NewX,NewY),full_output=1,warning=True)   

但我不知道如何更深入地解决这个问题。我认为这个问题可能与全局变量和局部变量之间的差异有关,但也许它是别的东西。

这是我的完整代码的当前草稿:

import numpy as np 
import matplotlib.pyplot as plt 
import scipy.optimize 

def GetMinRR(age):
    MaxHR = 208-(0.7*age)
    MinRR = (60/MaxHR)*1000
    return MinRR

def sigmoid(p,x):
    x0,y0,c,k=p 
    y = c / (1 + np.exp(-k*(x-x0))) + y0 
    return y 

def residuals(p,x,y): 
    return y - sigmoid(p,x) 

def resize(x,y,xmin=0.0,xmax=1.0,ymin=0.0,ymax=1.0):
    # Create local variables
    NewX = [t for t in x]
    NewY = [t for t in y]
    # If the mins are greater than the maxs, then flip them.
    if xmin>xmax: xmin,xmax=xmax,xmin 
    if ymin>ymax: ymin,ymax=ymax,ymin
    #----------------------------------------------------------------------------------------------    
    # The rest of the code below re-calculates all the values in x and then in y with these steps:
    #       1.) Subtract the actual minimum of the input x-vector from each value of x
    #       2.) Multiply each resulting value of x by the result of dividing the difference
    #           between the new xmin and xmax by the actual maximum of the input x-vector
    #       3.) Add the new minimum to each value of x
    # Note: I wrote in x-notation, but the identical process is also repeated for y
    #----------------------------------------------------------------------------------------------    
    # Subtracts right operand from the left operand and assigns the result to the left operand.
    # Note: c -= a is equivalent to c = c - a
    NewX -= x.min()

    # Multiplies right operand with the left operand and assigns the result to the left operand.
    # Note: c *= a is equivalent to c = c * a
    NewX *= (xmax-xmin)/NewX.max()

    # Adds right operand to the left operand and assigns the result to the left operand.
    # Note: c += a is equivalent to c = c + a
    NewX += xmin

    # Subtracts right operand from the left operand and assigns the result to the left operand.
    # Note: c -= a is equivalent to c = c - a
    NewY -= y.min()

    # Multiplies right operand with the left operand and assigns the result to the left operand.
    # Note: c *= a is equivalent to c = c * a
    NewY *= (ymax-ymin)/NewY.max()

    # Adds right operand to the left operand and assigns the result to the left operand.
    # Note: c += a is equivalent to c = c + a
    NewY += ymin

    return (NewX,NewY)

# Declare raw data for use in creating logistic regression equation
x = np.array([821,576,473,377,326],dtype='float') 
y = np.array([255,235,208,166,157],dtype='float') 

# Call resize() function to re-calculate coordinates that will be used for equation
MinRR=GetMinRR(50)
MaxRR=1200
minLVET=(y[4]/x[4])*MinRR
maxLVET=(y[0]/x[0])*MaxRR

#x,y=resize(x,y,xmin=0.3, ymin=0.3) 
NewX,NewY=resize(x,y,xmin=MinRR,xmax=MaxRR,ymin=minLVET,ymax=maxLVET) 
print 'x is:  ',x 
print 'y is:  ',y
print 'NewX is:  ',NewX
print 'NewY is:  ',NewY

# p_guess is the starting estimate for the minimization
p_guess=(np.median(x),np.median(y),1.0,1.0) 
New_p_guess=(np.median(NewX),np.median(NewY),1.0,1.0) 

# Calls the leastsq() function, which calls the residuals function with an initial
# guess for the parameters and with the x and y vectors.  The full_output means that
# the function returns all optional outputs.  Note that the residuals function also
# calls the sigmoid function.  This will return the parameters p that minimize the
# least squares error of the sigmoid function with respect to the original x and y
# coordinate vectors that are sent to it.
p, cov, infodict, mesg, ier = scipy.optimize.leastsq( 
    residuals,p_guess,args=(x,y),full_output=1,warning=True)   

New_p, New_cov, New_infodict, New_mesg, New_ier = scipy.optimize.leastsq( 
    residuals,New_p_guess,args=(NewX,NewY),full_output=1,warning=True)   

# Define the optimal values for each element of p that were returned by the leastsq() function.
x0,y0,c,k=p 
print('''Reference data:\ 
x0 = {x0} 
y0 = {y0} 
c = {c} 
k = {k} 
'''.format(x0=x0,y0=y0,c=c,k=k)) 

New_x0,New_y0,New_c,New_k=New_p 
print('''New data:\ 
New_x0 = {New_x0} 
New_y0 = {New_y0} 
New_c = {New_c} 
New_k = {New_k} 
'''.format(New_x0=New_x0,New_y0=New_y0,New_c=New_c,New_k=New_k))

# Create a numpy array of x-values
xp = np.linspace(x.min(), x.max(), x.max()-x.min())
New_xp = np.linspace(NewX.min(), NewX.max(), NewX.max()-NewX.min())
# Return a vector pxp containing all the y values corresponding with the x-values in xp
pxp=sigmoid(p,xp)
New_pxp=sigmoid(New_p,New_xp)

# Plot the results 
plt.plot(x, y, '>', xp, pxp, 'g-')
plt.plot(NewX, NewY, '^',New_xp, New_pxp, 'r-')
plt.xlabel('x')
plt.ylabel('y',rotation='horizontal')
plt.grid(True)
plt.show()
4

1 回答 1

2

尝试这个:

import numpy as np 
import matplotlib.pyplot as plt 
import scipy.optimize 

def GetMinRR(age):
    MaxHR = 208-(0.7*age)
    MinRR = (60/MaxHR)*1000
    return MinRR

def sigmoid(p,x):
    x0,y0,c,k=p 
    y = c / (1 + np.exp(-k*(x-x0))) + y0 
    return y 

def residuals(p,x,y): 
    return y - sigmoid(p,x) 

def resize(arr,lower=0.0,upper=1.0):
    # Create local copy
    result=arr.copy()
    # If the mins are greater than the maxs, then flip them.
    if lower>upper: lower,upper=upper,lower
    #----------------------------------------------------------------------------------------------    
    # The rest of the code below re-calculates all the values in x and then in y with these steps:
    #       1.) Subtract the actual minimum of the input x-vector from each value of x
    #       2.) Multiply each resulting value of x by the result of dividing the difference
    #           between the new xmin and xmax by the actual maximum of the input x-vector
    #       3.) Add the new minimum to each value of x
    #----------------------------------------------------------------------------------------------    
    # Subtracts right operand from the left operand and assigns the result to the left operand.
    # Note: c -= a is equivalent to c = c - a
    result -= result.min()

    # Multiplies right operand with the left operand and assigns the result to the left operand.
    # Note: c *= a is equivalent to c = c * a
    result *= (upper-lower)/result.max()

    # Adds right operand to the left operand and assigns the result to the left operand.
    # Note: c += a is equivalent to c = c + a
    result += lower
    return result


# Declare raw data for use in creating logistic regression equation
x = np.array([821,576,473,377,326],dtype='float') 
y = np.array([255,235,208,166,157],dtype='float') 

# Call resize() function to re-calculate coordinates that will be used for equation
MinRR=GetMinRR(50)
MaxRR=1200
# x[-1] returns the last value in x
minLVET=(y[-1]/x[-1])*MinRR
maxLVET=(y[0]/x[0])*MaxRR

print(MinRR, MaxRR)
#x,y=resize(x,y,xmin=0.3, ymin=0.3) 
NewX=resize(x,lower=MinRR,upper=MaxRR)
NewY=resize(y,lower=minLVET,upper=maxLVET) 
print 'x is:  ',x 
print 'y is:  ',y
print 'NewX is:  ',NewX
print 'NewY is:  ',NewY

# p_guess is the starting estimate for the minimization
p_guess=(np.median(x),np.min(y),np.max(y),0.01) 
New_p_guess=(np.median(NewX),np.min(NewY),np.max(NewY),0.01) 

# Calls the leastsq() function, which calls the residuals function with an initial
# guess for the parameters and with the x and y vectors.  The full_output means that
# the function returns all optional outputs.  Note that the residuals function also
# calls the sigmoid function.  This will return the parameters p that minimize the
# least squares error of the sigmoid function with respect to the original x and y
# coordinate vectors that are sent to it.
p, cov, infodict, mesg, ier = scipy.optimize.leastsq( 
    residuals,p_guess,args=(x,y),full_output=1,warning=True)   

New_p, New_cov, New_infodict, New_mesg, New_ier = scipy.optimize.leastsq( 
    residuals,New_p_guess,args=(NewX,NewY),full_output=1,warning=True)   

# Define the optimal values for each element of p that were returned by the leastsq() function.
x0,y0,c,k=p 
print('''Reference data:\ 
x0 = {x0} 
y0 = {y0} 
c = {c} 
k = {k} 
'''.format(x0=x0,y0=y0,c=c,k=k)) 

New_x0,New_y0,New_c,New_k=New_p 
print('''New data:\ 
New_x0 = {New_x0} 
New_y0 = {New_y0} 
New_c = {New_c} 
New_k = {New_k} 
'''.format(New_x0=New_x0,New_y0=New_y0,New_c=New_c,New_k=New_k))

# Create a numpy array of x-values
xp = np.linspace(x.min(), x.max(), x.max()-x.min())
New_xp = np.linspace(NewX.min(), NewX.max(), NewX.max()-NewX.min())
# Return a vector pxp containing all the y values corresponding with the x-values in xp
pxp=sigmoid(p,xp)
New_pxp=sigmoid(New_p,New_xp)

# Plot the results 
plt.plot(x, y, '>', xp, pxp, 'g-')
plt.plot(NewX, NewY, '^',New_xp, New_pxp, 'r-')
plt.xlabel('x')
plt.ylabel('y',rotation='horizontal')
plt.grid(True)
plt.show()

替代文字

您的其他相关问题尚未结束,您似乎已经注册了两次,并且 stackoverflow 不允许您编辑其他问题,因为它无法识别此用户与此用户 相同。

主要是我在上面的代码中所做的就是改变New_p_guess. 为初始猜测找到正确的值是一种艺术。如果可以通过算法完成,scipy 就不会要求您这样做。一点点分析以及对数据的“感觉”都会有所帮助。提前知道解决方案应该大致是什么样子,因此在问题的上下文中什么值是合理的也有帮助。(这只是说我猜到了我选择 k=0.01 的方式。)

于 2010-12-02T00:41:07.263 回答