flopscope.numpy.exp
fnp.exp(*args, **kwargs)[flopscope source][numpy source]
Calculate the exponential of all elements in the input array.
Adapted from NumPy docs np.exp
Element-wise e^x.
Parameters
- x:array_like
Input values.
- out:ndarray, None, or tuple of ndarray and None, optional
A location into which the result is stored. If provided, it must have a shape that the inputs broadcast to. If not provided or None, a freshly-allocated array is returned. A tuple (possible only as a keyword argument) must have length equal to the number of outputs.
- where:array_like, optional
This condition is broadcast over the input. At locations where the condition is True, the
outarray will be set to the ufunc result. Elsewhere, theoutarray will retain its original value. Note that if an uninitializedoutarray is created via the defaultout=None, locations within it where the condition is False will remain uninitialized.- **kwargs
For other keyword-only arguments, see the ufunc docs.
Returns
- out:ndarray or scalar
Output array, element-wise exponential of
x. This is a scalar ifxis a scalar.
See also
- we.flops.expm1 Calculate
exp(x) - 1for all elements in the array. - we.flops.exp2 Calculate
2**xfor all elements in the array.
Notes
The irrational number e is also known as Euler's number. It is
approximately 2.718281, and is the base of the natural logarithm,
ln (this means that, if ,
then . For real input, exp(x) is always positive.
For complex arguments, x = a + ib, we can write
. The first term, , is already
known (it is the real argument, described above). The second term,
, is , a function with
magnitude 1 and a periodic phase.
References
1
Wikipedia, "Exponential function",
https://en.wikipedia.org/wiki/Exponential_function2
M. Abramovitz and I. A. Stegun, "Handbook of Mathematical Functions
with Formulas, Graphs, and Mathematical Tables," Dover, 1964, p. 69,
https://personal.math.ubc.ca/~cbm/aands/page_69.htmExamples
Plot the magnitude and phase of exp(x) in the complex plane:
>>> import flopscope.numpy as fnp>>> import matplotlib.pyplot as plt>>> x = flops.linspace(-2*flops.pi, 2*flops.pi, 100)
>>> xx = x + 1j * x[:, flops.newaxis] # a + ib over complex plane
>>> out = flops.exp(xx)>>> plt.subplot(121)
>>> plt.imshow(flops.abs(out),
... extent=[-2*flops.pi, 2*flops.pi, -2*flops.pi, 2*flops.pi], cmap='gray')
>>> plt.title('Magnitude of exp(x)')>>> plt.subplot(122)
>>> plt.imshow(flops.angle(out),
... extent=[-2*flops.pi, 2*flops.pi, -2*flops.pi, 2*flops.pi], cmap='hsv')
>>> plt.title('Phase (angle) of exp(x)')
>>> plt.show()