# [PD] [OT] "processing" application

Mathieu Bouchard matju at artengine.ca
Sun Oct 15 13:42:09 CEST 2006

```On Sat, 14 Oct 2006, Martin Peach wrote:

>> It's an integer multiplied by a power of two. That's about as layman as it
>> can reasonably get. In Pd the integer is between 2^23 and 2^24 and the
>> power of two is between 2^-149 and 2^106.
> It's not exactly an integer since it's supposed to be a fixed point number
> between 1 and just less than 2,  multiplied by a power of two.

did you realize that your definition and my definition are equivalent ?

why do you think that i say that the multiplicator is between 2^-149 and
2^106, instead of 2^-127 to 2^129 ? (note: that is an off-by-one error,
so I really meant 2^-150 to 2^105)

> In the float the binary point starts out at the left and the
> power effectively moves it.

It can "start" anywhere you want, provided that the relation between
"characteristic" and "exponent" is appropriately chosen...

> The thing about the laity is that they are free to learn on their own
> and can thereby acquire even more knowledge than those who have gone
> through the system which only tells them what it wants them to know.

Exactly. This allows me to teach floats in an alternative way that doesn't
involve putting the binary point to the left.

> For example this is the representation of the number 1.5 X 2^20 = 1572864
> (aka UNITBIT32) in
> IEEE Standard 754 Double Precision Storage Format (double):

I was only talking about single precision floats, because that's the only
thing that PureData supports today.

_ _ __ ___ _____ ________ _____________ _____________________ ...
| Mathieu Bouchard - tél:+1.514.383.3801 - http://artengine.ca/matju
| Freelance Digital Arts Engineer, Montréal QC Canada
```