What's a good way to add a large number of small floats together?

Posted by splicer on Stack Overflow See other posts from Stack Overflow or by splicer
Published on 2010-03-16T16:49:25Z Indexed on 2010/03/16 16:51 UTC
Read the original article Hit count: 162

Filed under:

floating-point

|

float

|

numerical

|

algorithm

Say you have 100000000 32-bit floating point values in an array, and each of these floats has a value between 0.0 and 1.0. If you tried to sum them all up like this

result = 0.0;
for (i = 0; i < 100000000; i++) {
    result += array[i];
}

you'd run into problems as result gets much larger than 1.0.

So what are some of the ways to more accurately perform the summation?

© Stack Overflow or respective owner

Related posts about floating-point

understanding floating point variables

as seen on Stack Overflow - Search for 'Stack Overflow'
There is some problem, i can't understand anyway. look at this code please <script type="text/javascript"> function math(x) { var y; y = x*10; alert(y); } </script> <input type="button" onclick="math(0.011)"> What must be alerted after i click on button? i think 0.11… >>> More
Comparing floating point values

as seen on Stack Overflow - Search for 'Stack Overflow'
I just read a statement about the floating point value comparison Floating point values shall not be compared using either the == or != operators. Most floating point values have no exact binary representation and have a limited precision. If so what is the best method for comparing two floating… >>> More
floating point hex octal binary

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I am working on a calculator that allows you to perform calculations past the decimal point in octal, hexadecimal, binary, and of course decimal. I am having trouble though finding a way to convert floating point decimal numbers to floating point hexadecimal, octal, binary and vice versa. The… >>> More
What is a Bias Value of Floating Point Numbers?

as seen on Stack Overflow - Search for 'Stack Overflow'
In learning how floating point numbers are represented in computers I have come across the term "bias value" that I do not quite understand. The bias value in floating point numbers has to do with the negative and positiveness of the exponent part of a floating point number. The bias value of a… >>> More
Why are floating point values so prolific?

as seen on Stack Overflow - Search for 'Stack Overflow'
So, title says it all. Why are floating point values so prolific in computer programming. Due to problems like rounding errors, and not being able to even accurately represent numbers such as 0.1, I really can't see how they got as far as they did. I understand that the computation is faster… >>> More

Related posts about float

Simplex Noise Help

as seen on Game Development - Search for 'Game Development'
Im Making A Minecraft Like Gae In XNA C# And I Need To Generate Land With Caves This Is The Code For Simplex I Have /// <summary> /// 1D simplex noise /// </summary> /// <param name="x"></param> /// <returns></returns> public static float… >>> More
IE7 div boxes with clear: right and float: left - float to top

as seen on Stack Overflow - Search for 'Stack Overflow'
Hey, lately i've been slamming my head against my desk to solve this Problem. Didn't work out. I know it can be solved by editing the contents with some clearing elements. Sadly there is some javascript sorting beeing used and the Sourcode is being generated by CMS Components so that would be my… >>> More
Help with Collision Resolution?

as seen on Game Development - Search for 'Game Development'
I'm trying to learn about physics by trying to make a simplified GTA 2 clone. My only problem is collision resolution. Everything else works great. I have a rigid body class and from there cars and a wheel class: class RigidBody extends Entity { //linear private Vector2D velocity = new Vector2D(); … >>> More
Point inside Oriented Bounding Box?

as seen on Game Development - Search for 'Game Development'
I have an OBB2D class based on SAT. This is my point in OBB method: public boolean pointInside(float x, float y) { float newy = (float) (Math.sin(angle) * (y - center.y) + Math.cos(angle) * (x - center.x)); float newx = (float) (Math.cos(angle) * (x - center.x) - Math.sin(angle)… >>> More
Solving a difficult incomplete type error

as seen on Stack Overflow - Search for 'Stack Overflow'
I get an incomplete type error when trying to compile my code. I know that it is related to includes, but my project is large and it uses several templates so I can't find which type is actually incomplete. The error message doesn't help either: Compiling: ../../../addons/ofxTableGestures/src/Graphics/objects/CursorFeedback… >>> More