The beginning of infinity in JavaScript

By -
Infinity begins relatively early in JavaScript:

    > Math.pow(2, 1024)
    Infinity
    > Math.pow(2, 1023)
    8.98846567431158e+307

What is going on here?


All numbers in JavaScript are floating point numbers and (roughly) encoded internally [1] as


1.f × 2p

This is the most common way of representing floating point numbers. The left-hand side of the multiplication comprises the digits, the right-hand side moves the dot to the correct position (to the left if it is negative, to the right if it is positive).


The mantissa is a binary 1, followed by a binary dot, followed by a 52 bit fraction f. The 11 bit exponent p has to be in the range


−1023 < p < 1024

Thus, the exponent of Math.pow(2, 1024) is out of range and Infinity is an error result.


Consult [1] if you want to know more about how numbers are encoded in JavaScript.

Reference




  1. How numbers are encoded in JavaScript


Comments

Post a Comment

Popular posts from this blog

Joy*

By -
Image
The quiet, old, musty-smelling, echoes of history. The library has survived fires, earthquakes, floods. This makes it biblical, mythological, the field of Elysium for the mind life. I have come to this library in late spring to read, to write, to consider where my life is going. All the students have left, and I am alone with my thoughts, and the thoughts of those lining the shelves. Mute testimonies from another age. I hear the voices calling me . I walk between the stacks, selecting random volumes: 1909, 1921, 1894, 1910. The spines are creased and lined, the type worn away. I open the books and find some have not been checked out since the 1950s. There they sit, waiting patiently for someone to come along and bring them to life again by reading. The library is a four-story affair built on the side of a hill. You enter on the third floor. Spanish colonial architecture, all arches and vaulted ceilings. This is the reading area, now filled with computer stations. Above is a sort of ba...
Keep reading

Maya Angelou

By -
Image
The thing I most appreciate about celebrated writer, Maya Angelou , is her bravery.   She spoke and wrote what was on her mind, never mincing words.   In today’s world of empty praise and false positive affirmation, this poet is a fresh ocean breeze in the heat of summer.   I love her poetry and I teach it often along with her memoir, I Know Why The Caged Bird Sings .   Her work connects back to the Harlem Renaissance writers and other African-American artists.   The title of her memoir comes from a poem by Paul Lawrence Dunbar (1872-1906).   However, she is not an artist addressing a particular race; she is a poet for the ages and for all people, a true American treasure. The Washington Post published a piece yesterday by Valerie Strauss that made clear Angelou’s ability to speak the truth.   She was exuberant about the election of President Obama, and he in turn awarded her the Presidential Medal of Freedom in 2011.   However, she often spo...
Keep reading

No Strangers To Tragedy

By -
Image
Courtesy CBS News Two recent stories continue to haunt me, as I’m sure they haunt the rest of the nation. At a Pennsylvania high school , young Alex Hribal, age 16, greeted his fellow students one morning last week by stabbing 21 of them with a set of kitchen knives.   He also attacked a school security officer.   Four of his victims remain in critical condition. Tomorrow, the school will reopen so parents and students can do a walk-through.   The school plant has been cleaned and sanitized of the blood and gore, but the fear, I’m afraid, will be much harder to clean away.   Classes begin on Wednesday, but it is safe to say no one in the community will be the same again. Hribal did not stand out as a troubled teen before the rampage.   Mental illness does not necessarily broadcast its presence to the world before bullets fly or steel flashes, bloodstained and corroded, in a school hallway.   There are sleepers out there, psychologists warn us.   Some...
Keep reading