math - Read For Learn

How do you find the rightmost digit of an integer?

x % 10 looks like the correct answer. But is not. -2 % 10 is either -2 or 8 depending on language/implementation/whatever. And neither is actually “last digit”. So the correct answer is abs(x) % 10.

Lua replacement for the % operator

It’s not ideal, but according to the Lua 5.2 Reference Manual: a % b == a – math.floor(a/b)*b

How to round a number to significant figures in Python

You can use negative numbers to round integers: Thus if you need only most significant digit: You’ll probably have to take care of turning float to integer if it’s bigger than 1.

Infinite integer in Python

Taken from here: https://www.gnu.org/software/libc/manual/html_node/Infinity-and-NaN.html IEEE 754 floating point numbers can represent positive or negative infinity, and NaN (not a number) That is, the representation of float and Decimal can store these special values. However, there is nothing within the basic type int that can store the same. As you exceed the limit of 2^32 in an unsigned 32-bit int, you simply roll … Read more

Clamping floating numbers in Python?

There’s no such function, but will do the trick.

How can I convert radians to degrees with Python?

Python includes two functions in the math package; radians converts degrees to radians, and degrees converts radians to degrees. To match the output of your calculator you need: Note that all of the trig functions convert between an angle and the ratio of two sides of a triangle. cos, sin, and tan take an angle in radians as input and return … Read more

How can I use numpy.correlate to do autocorrelation?

To answer your first question, numpy.correlate(a, v, mode) is performing the convolution of a with the reverse of v and giving the results clipped by the specified mode. The definition of convolution, C(t)=∑ -∞ < i < ∞ aivt+i where -∞ < t < ∞, allows for results from -∞ to ∞, but you obviously can’t store an infinitely long array. So it has to … Read more