Given the start, stop and step values, where start > stop and step < 0, how can I convert the values so that start < stop and step > 0 and use these values in a for loop that can yield the same index but in a reverse way. In other words, what should be the mathematical formula to use
Tag: math
How is python’s float.__eq__ implemented in the language?
I know that the best way to compare two floats for equality is usually to use math.isclose(float_a, float_b). But I was curious to know how python does it if you simply do float_a == float_b. I suppose it’s implemented in C, but what is the logic behind it ? Answer Here is the source code for float obje…
Round to the next tens in Python
Is there a way to round always up to the next tens? E.g., 0.000000000003 shall become 0.1. 0.1244593249234 shall become 0.2 and 0.9x shall become 1. Negative numbers are not a thing here. Is there a built in or do I need to come up with something? Answer by multiplying the input f to 10, you will map it from
Why is my conical/angle gradient image distorted?
I’m currently trying to create a conical gradient, and it kind of works. However, it doesn’t look quite right and I can’t wrap my hand around to why: The line that goes up from the center is slightly angled to the right and at the bottom there is a visible (not too noticable) line. Code is a…
Unsupported operand types ‘NoneType’
I am very new to Python, and I’m trying to create a software that calculates a series of equations and I keep running into an error. This is the code: My goal is that the code runs these equations until v_i equals 0, while populating the lists with the relevant results, then throwing all the information…
Unexpected result in the numerical calculation – (invalid value encountered in double_scalar )
The result is I am having troubling to understand the problem here. It’s clear that I can print the x, but I cannot take the power of it. Meanwhile when I write the code as I get I am literally shocked. I cannot understand what is going on. If I just put the numbers manually I can calculate the result.
math module not working in a string for eval
Suppose I have this code: but I only get this error: NameError: name ‘math’ is not defined How can I fix this? Answer The second parameter to eval, if present, should reference the global namespace. Here, you explicitely assigned an empty dict to it, so you don’t have any access to the name …
Adding functions y(x) together in python – impossible?
I’m currently trying to solve an engineering problem where I need to solve relatively long differential equations, for which I’m using the method odeint from scipy. I changed my problem to more easy variables and equations to shorten the code below and make it clearer. I want to add two parts of a…
Faster matrix calculation in numpy
Is there some faster variant of computing the following matrix (from this paper), given a nxn matrix M and a n-vector X: ? I currently compute it as follows: This is very slow, but I suspect there is a nicer “numpythonic” way of doing this instead of looping… EDIT: While all answers work and…
Python while loop not working as intended
I don’t know how to get over this problem with while loop. So basically I want to return the number of zeros at the end of a number’s factorial. After the while loop runs only 1 time, it breaks; I don’t know why. Help would be very appreciated. Thanks! Answer After multiplying your value by …