Questions tagged [numerical-analysis]
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6
questions
14
votes
5answers
3k views
Is 2**x faster to compute than exp(x)?
Forgive the naïveté that will be obvious in the way I ask this question as well as the fact that I'm asking it.
Mathematicians typically use $\exp$ as it's the simplest/nicest base in ...
13
votes
1answer
770 views
Overflow safe summation
Suppose I am given $n$ fixed width integers (i.e. they fit in a register of width $w$), $a_1, a_2, \dots a_n$ such that their sum $a_1 + a_2 + \dots + a_n = S$ also fits in a register of width $w$.
...
8
votes
2answers
800 views
Is “ternary search” an appropriate term for the algorithm that optimizes a unimodal function on a real interval?
Suppose that I want to optimize a unimodal function defined on some real interval. I can use the well-known algorithm as described in Wikipedia under the name of ternary search.
In case of the ...
8
votes
2answers
682 views
Detecting overflow in summation
Suppose I am given an array of $n$ fixed width integers (i.e. they fit in a register of width $w$), $a_1, a_2, \dots a_n$. I want to compute the sum $S = a_1 + \ldots + a_n$ on a machine with 2's ...
asked Apr 22 '12 at 1:16
Gilles 'SO- stop being evil'
40.1k7 gold badges108 silver badges171 bronze badges
5
votes
4answers
416 views
Is order of matrix multiplication affecting numerical accuracy of the result?
I have to multiply three matrices of floats: A (100x8000), B (8000x27) and C (27x1).
Is ...
2
votes
1answer
72 views
Proof that a guard digit bound the error of subtraction
I was reading What Every Computer Scientist Should Know About Floating-Point Arithmetic, which is extremely interesting. But I have some troubles understanding the proof of Theorem 9 (page 33).
First ...
