小于1的数的参数变化

Question

我正在用下面的代码解一个方程：

from numpy import arange
wt=647
wp=119000
e0=10983849
w = arange(0, 1000)
e = e0-(wp**2/(w*2+wt))
plot(w, e)

不过，我希望w的变化不是从0到1000或100，而是从5到6，每个数字之间有100步

变量应该有100个步骤，例如，w变量为[5.01，5.02，5.03，5.04，5.05。。。[第5.98、5.99、6.00段]

有人知道怎么做吗

Answer 1

使用^{}：

In [217]: np.linspace(5.01, 6, 100)
Out[217]: 
array([ 5.01,  5.02,  5.03,  5.04,  5.05,  5.06,  5.07,  5.08,  5.09,
        5.1 ,  5.11,  5.12,  5.13,  5.14,  5.15,  5.16,  5.17,  5.18,
        5.19,  5.2 ,  5.21,  5.22,  5.23,  5.24,  5.25,  5.26,  5.27,
        5.28,  5.29,  5.3 ,  5.31,  5.32,  5.33,  5.34,  5.35,  5.36,
        5.37,  5.38,  5.39,  5.4 ,  5.41,  5.42,  5.43,  5.44,  5.45,
        5.46,  5.47,  5.48,  5.49,  5.5 ,  5.51,  5.52,  5.53,  5.54,
        5.55,  5.56,  5.57,  5.58,  5.59,  5.6 ,  5.61,  5.62,  5.63,
        5.64,  5.65,  5.66,  5.67,  5.68,  5.69,  5.7 ,  5.71,  5.72,
        5.73,  5.74,  5.75,  5.76,  5.77,  5.78,  5.79,  5.8 ,  5.81,
        5.82,  5.83,  5.84,  5.85,  5.86,  5.87,  5.88,  5.89,  5.9 ,
        5.91,  5.92,  5.93,  5.94,  5.95,  5.96,  5.97,  5.98,  5.99,  6.  ])

np.arange和np.linspace通常用于返回等距数字arange显式指定step，而linspace使用(stop-start)/(num-1)隐式计算步长

Answer 2

^{} function采用可选的step参数：

>>> arange(5, 6.01, .01)
array([ 5.  ,  5.01,  5.02,  5.03,  5.04,  5.05,  5.06,  5.07,  5.08,
        5.09,  5.1 ,  5.11,  5.12,  5.13,  5.14,  5.15,  5.16,  5.17,
        5.18,  5.19,  5.2 ,  5.21,  5.22,  5.23,  5.24,  5.25,  5.26,
        5.27,  5.28,  5.29,  5.3 ,  5.31,  5.32,  5.33,  5.34,  5.35,
        5.36,  5.37,  5.38,  5.39,  5.4 ,  5.41,  5.42,  5.43,  5.44,
        5.45,  5.46,  5.47,  5.48,  5.49,  5.5 ,  5.51,  5.52,  5.53,
        5.54,  5.55,  5.56,  5.57,  5.58,  5.59,  5.6 ,  5.61,  5.62,
        5.63,  5.64,  5.65,  5.66,  5.67,  5.68,  5.69,  5.7 ,  5.71,
        5.72,  5.73,  5.74,  5.75,  5.76,  5.77,  5.78,  5.79,  5.8 ,
        5.81,  5.82,  5.83,  5.84,  5.85,  5.86,  5.87,  5.88,  5.89,
        5.9 ,  5.91,  5.92,  5.93,  5.94,  5.95,  5.96,  5.97,  5.98,
        5.99,  6.  ])

Answer 3

您只需要指定np.arange的step参数。例如：

>>> np.arange(0, 1, .1)
[ 0.   0.1  0.2  0.3  0.4  0.5  0.6  0.7  0.8  0.9]

或者，可以使用np.linspace，指定在给定的间隔中需要多少数字：

>>> np.linspace(0, 0.9, 10)
[ 0.   0.1  0.2  0.3  0.4  0.5  0.6  0.7  0.8  0.9]

有关更多信息，请参阅Numpy文档

• http://docs.scipy.org/doc/numpy/reference/generated/numpy.linspace.html
• http://docs.scipy.org/doc/numpy/reference/generated/numpy.arange.html