How can a query multiply 2 cell for each row MySQL?
Use this: SELECT Pieces, Price, Pieces * Price as ‘Total’ FROM myTable
multiplication
pandas dataframe multiply with a series [duplicate]
What’s wrong with result = dataframe.mul(series, axis=0) ? https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.mul.html#pandas.DataFrame.mul
Why is division more expensive than multiplication?
CPU’s ALU (Arithmetic-Logic Unit) executes algorithms, though they are implemented in hardware. Classic multiplications algorithms includes Wallace tree and Dadda tree. More information is available here. More sophisticated techniques are available in newer processors. Generally, processors strive to parallelize bit-pairs operations in order the minimize the clock cycles required. Multiplication algorithms can be parallelized quite … Read more
How to multiply individual elements of a list with a number?
In NumPy it is quite simple import numpy as np P=2.45 S=[22, 33, 45.6, 21.6, 51.8] SP = P*np.array(S) I recommend taking a look at the NumPy tutorial for an explanation of the full capabilities of NumPy’s arrays: https://scipy.github.io/old-wiki/pages/Tentative_NumPy_Tutorial
Is integer multiplication really done at the same speed as addition on a modern CPU?
Multiplication of two n-bit numbers can in fact be done in O(log n) circuit depth, just like addition. Addition in O(log n) is done by splitting the number in half and (recursively) adding the two parts in parallel, where the upper half is solved for both the “0-carry” and “1-carry” case. Once the lower half … Read more
How to multiply all integers inside list [duplicate]
Try a list comprehension: l = [x * 2 for x in l] This goes through l, multiplying each element by two. Of course, there’s more than one way to do it. If you’re into lambda functions and map, you can even do l = map(lambda x: x * 2, l) to apply the function … Read more
Multiply rows of matrix by vector?
I think you’re looking for sweep(). # Create example data and vector mat <- matrix(rep(1:3,each=5),nrow=3,ncol=5,byrow=TRUE) [,1] [,2] [,3] [,4] [,5] [1,] 1 1 1 1 1 [2,] 2 2 2 2 2 [3,] 3 3 3 3 3 vec <- 1:5 # Use sweep to apply the vector with the multiply (`*`) function # across … Read more
Catch and compute overflow during multiplication of two large integers
1. Detecting the overflow: x = a * b; if (a != 0 && x / a != b) { // overflow handling } Edit: Fixed division by 0 (thanks Mark!) 2. Computing the carry is quite involved. One approach is to split both operands into half-words, then apply long multiplication to the half-words: uint64_t … Read more
How can I multiply and divide using only bit shifting and adding?
To multiply in terms of adding and shifting you want to decompose one of the numbers by powers of two, like so: 21 * 5 = 10101_2 * 101_2 (Initial step) = 10101_2 * (1 * 2^2 + 0 * 2^1 + 1 * 2^0) = 10101_2 * 2^2 + 10101_2 * 2^0 = 10101_2 … Read more
How to perform element-wise multiplication of two lists? [duplicate]
Use a list comprehension mixed with zip():. [a*b for a,b in zip(lista,listb)]