提取`scipy.optimize.newton()`结果的收敛布尔值。

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英文:

Extracting the converged? bool of scipy.optimize.newton() result

问题

Sure, here is the translated code part:

我正在尝试使用scipy.optimize.newton()找到函数的根我使用的函数非常复杂因此我决定进行一定次数的迭代并在精度不被满足时保留最终答案因此我想知道何时发生了收敛何时没有在一个布尔变量中表示

我遇到的问题是newton()返回一个二维数组其中根的结果是第一个值第二个值是一个具有多个值的对象我似乎无法提取出收敛的值

我尝试只查看newton返回函数的第二个值这是我的代码

from scipy.optimize import newton

def function(x):
    return x**2-1

def fprime(x):
    return 2*x

x0=5

test = newton(function, x0, fprime=None, args=(), tol=1.48e-08, maxiter=5, fprime2=None, x1=None, rtol=0.0, full_output=True, disp=False)

print(test[1])

这将产生以下输出:

      converged: False
           flag: 'convergence error'
 function_calls: 7
     iterations: 5
           root: 1.0103336911991998

你想要的是一个仅包含'False'的变量(对于这个示例)。

英文:

I'm trying to find the <strike>minimum</strike> root of a function using scipy.optimize.newton(). The function I'm using is very complicated, and as a result I decided to have a set number of iterations and to keep the final answer even if the precision asked is not respected. As such, I would like to know when convergence happened and when it didn't, in one single bool variable.

The problem I'm running in is that newton() returns a 2 dimensional array with the root result as the first value, and the second value is an object with several values, of which I can't seem to extract the converged one.

I tried to look only at the second value of the newton return function. This is my code:

from scipy.optimize import newton

def function(x):
    return x**2-1

def fprime(x):
    return 2*x

x0=5

test = newton(function, x0, fprime=None, args=(), tol=1.48e-08, maxiter=5, fprime2=None, x1=None, rtol=0.0, full_output=True, disp=False)


print(test[1])

Which gives

      converged: False
           flag: &#39;convergence error&#39;
 function_calls: 7
     iterations: 5
           root: 1.0103336911991998

and what I would like is just one variable with 'False' in it (for this example)

答案1

得分: 0

在调用 scipy.optimize.newton 时,newton 返回一个包含两个元素的元组,第一个元素是根,第二个元素是一个 RootResults 对象。如果你想获取 RootResults 对象的 converged 属性,只需使用点表示法,即 some_obj.attribute

root, r = newton(function, x0, fprime=None, args=(), tol=1.48e-08, maxiter=5, fprime2=None, x1=None, rtol=0.0, full_output=True, disp=False)
converged_flag = r.converged
print(converged_flag)
英文:

In your way of calling scipy.optimize.newton, newton returns a 2-element tuple, and the first element is the root, the second is a RootResults object. If you want to get the converged attribute of the RootResults object, you just need to
use dot notation, some_obj.attribute.

root, r = newton(function, x0, fprime=None, args=(), tol=1.48e-08, maxiter=5, fprime2=None, x1=None, rtol=0.0, full_output=True, disp=False)
converged_flag = r.converged
print(converged_flag)

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  • 本文由 发表于 2023年6月26日 16:28:56
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