exponentiation

Iterative logarithmic exponentiation

。_饼干妹妹 提交于 2021-02-08 02:01:55
问题 I bombed an interview (phone screen with collabedit) recently. Here is the question: Write an interative O(lg n) algorithm for finding the power of x^y (x is a double, y>0 is an int). I first did the recursive divide and conquer one and tried to convert it to iterative... and I couldn't :S Is there a method to convert recursion to iterative (it is easy for tail recursion, but how about recursive functions with two possible recursive calls which depend on conditions to decide which call will

Iterative logarithmic exponentiation

六眼飞鱼酱① 提交于 2021-02-08 02:01:36
问题 I bombed an interview (phone screen with collabedit) recently. Here is the question: Write an interative O(lg n) algorithm for finding the power of x^y (x is a double, y>0 is an int). I first did the recursive divide and conquer one and tried to convert it to iterative... and I couldn't :S Is there a method to convert recursion to iterative (it is easy for tail recursion, but how about recursive functions with two possible recursive calls which depend on conditions to decide which call will

Why does Python `**` use for exponentiation instead of the `^` operator? [duplicate]

假如想象 提交于 2021-02-04 21:59:30
问题 This question already has answers here : What do these operators mean (** , ^ , %, //)? [closed] (3 answers) Closed 2 years ago . Why is ^ not squaring in Python? I know exponentiation is ** instead, but what exactly is ^ and why wasn't that operator used instead? For example 2^2=0 , 3^2=1 . 回答1: The ^ operator was already used for bitwise xor. >>> x = 42; format(x, '08b') '00101010' >>> y = 137; format(y, '08b') '10001001' >>> z = x ^ y; format(z, '08b') '10100011' That leaves the old

Why does Python `**` use for exponentiation instead of the `^` operator? [duplicate]

前提是你 提交于 2021-02-04 21:58:30
问题 This question already has answers here : What do these operators mean (** , ^ , %, //)? [closed] (3 answers) Closed 2 years ago . Why is ^ not squaring in Python? I know exponentiation is ** instead, but what exactly is ^ and why wasn't that operator used instead? For example 2^2=0 , 3^2=1 . 回答1: The ^ operator was already used for bitwise xor. >>> x = 42; format(x, '08b') '00101010' >>> y = 137; format(y, '08b') '10001001' >>> z = x ^ y; format(z, '08b') '10100011' That leaves the old

Exponentiation in Fortran/gfortran to high precision

时光总嘲笑我的痴心妄想 提交于 2021-01-28 04:45:34
问题 How does gfortran handle exponentiation with a integer vs a real? I always assumed it was the same, but consider the example: program main implicit none integer, parameter :: dp = selected_real_kind(33,4931) real(kind=dp) :: x = 82.4754500815524510_dp print *, x print *, x**4 print *, x**4.0_dp end program main Compiling with gfortran gives 82.4754500815524510000000000000000003 46269923.0191143410452125643548442147 46269923.0191143410452125643548442211 Now clearly these numbers almost agree -

Difference between ECMAScript 2016 exponentiation operator and Math.pow()

天涯浪子 提交于 2020-12-25 01:38:55
问题 What is the benefit to using the ECMAScript 2016 exponentiation operator over the current Math.pow() ? In other words, besides reducing key strokes, what is the difference between Math.pow(2, 2) => 4 and 2 ** 2 => 4 回答1: None. As you can read in the ES7 spec, both Math.pow and the ** exponentation operator cast their arguments/operands to numbers and use the very same algorithm to determine the result. Addendum : this changed with the introduction of the BigInt type in ES2020, whose values

Difference between ECMAScript 2016 exponentiation operator and Math.pow()

≯℡__Kan透↙ 提交于 2020-12-25 01:38:33
问题 What is the benefit to using the ECMAScript 2016 exponentiation operator over the current Math.pow() ? In other words, besides reducing key strokes, what is the difference between Math.pow(2, 2) => 4 and 2 ** 2 => 4 回答1: None. As you can read in the ES7 spec, both Math.pow and the ** exponentation operator cast their arguments/operands to numbers and use the very same algorithm to determine the result. Addendum : this changed with the introduction of the BigInt type in ES2020, whose values

R: Exponent returning infinity

只谈情不闲聊 提交于 2020-08-12 01:29:28
问题 I need to remove logarithms of my data and thus am taking e to the power of the values which are logarithmed. My issue is that when I have e to the power of more than 709 R returns the value of infinity. How can I surpass this? e^710 [1] Inf Thanks :) 回答1: If you really want to work with numbers that big you can use a Rmpfr package. library('Rmpfr') x <- mpfr(710, precBits = 106) exp(x) 1 'mpfr' number of precision 106 bits [1] 2.233994766161711031253644458116e308 来源: https://stackoverflow