+- Python Forum (https://python-forum.io)
+-- Forum: Python Coding (https://python-forum.io/forum-7.html)
+--- Forum: Data Science (https://python-forum.io/forum-44.html)
+--- Thread: Creating step function (/thread-34369.html)
Creating step function - erdemath - Jul-25-2021
Hi,
For some time dependent biophysical model, I´m trying to visualize the certain
impulses occured on certain time. I define some step function below called as
>> The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
I do so, but then the results is not what I want. I just want to get the value 150.0 and 50. at specific
time range.
# ............................... The Code ........................................#
import matplotlib.pyplot as plt
import numpy as np
# Start and end time (in milliseconds)
tmin = 0.0
tmax = 50.0
# Time values
T = np.linspace(tmin, tmax, 5000)
# Input stimulus
def Id(t):
if 0.0 < t < 1.0:
return 150.0
elif 10.0 < t < 11.0:
return 50.0
return 0.0
# Input stimulus
Idv = Id(T)
#Idv = [Id(t) for t in T]
fig, ax = plt.subplots(figsize=(12, 7))
ax.plot(T, Idv)
ax.set_xlabel('Time (ms)')
ax.set_ylabel(r'Current density (uA/$cm^2$)')
ax.set_title('Stimulus (Current density)')
plt.grid()
# .................................................................................................#
RE: Creating step function - Gribouillis - Jul-25-2021
Occasional numpy user here, the following example may help
>>> import numpy as np
>>> t = np.linspace(0, 12, 30)
>>> t
array([ 0. , 0.4137931 , 0.82758621, 1.24137931, 1.65517241,
2.06896552, 2.48275862, 2.89655172, 3.31034483, 3.72413793,
4.13793103, 4.55172414, 4.96551724, 5.37931034, 5.79310345,
6.20689655, 6.62068966, 7.03448276, 7.44827586, 7.86206897,
8.27586207, 8.68965517, 9.10344828, 9.51724138, 9.93103448,
10.34482759, 10.75862069, 11.17241379, 11.5862069 , 12. ])
>>> np.where(np.logical_and(0 < t, t < 1), 150.0, 0.0) + np.where(np.logical_and(10.0 < t, t < 11.0), 50.0, 0.0)
array([ 0., 150., 150., 0., 0., 0., 0., 0., 0., 0., 0.,
0., 0., 0., 0., 0., 0., 0., 0., 0., 0., 0.,
0., 0., 0., 50., 50., 0., 0., 0.])