Re: storing floating point data with using float or double
- From: "Greg Young" <DruckDruckGoose@xxxxxxxxxxx>
- Date: Fri, 5 May 2006 12:47:06 -0400
If your data posted is typical of your data ... why not just store
(int16) data * 100
then on the way out just divide by 100 ? :)
Cheers,
Greg
"Steve" <skle@xxxxxxxx> wrote in message
news:uNwCiGGcGHA.864@xxxxxxxxxxxxxxxxxxxxxxx
Hi,
I've developed a testing application that stores formatted results in a
database. Recently it was requested that I add the ability to generate
graphs from the raw, un formatted test results (100,000+ float values)
I don't intend to store all of the 100,000 datapoints, but rather a subset
of say 250. Due to the volume of testing that we need and the volume of
results stored, I need to be VERY careful with data size and keep things
as lean and small as possible.
Given the example data: (-5.2485, 5.9875, -1.2548, 7.5842)
Those samples represent our data value boundaries, they won't get any
bigger than that, they are signed and they are floating point.
I don't need the precision of a float, the above values would be fine to
be stored as:
-5.29
5.99
-1.25
7.58
A couple of ideas I have come up with is to try compressing the array of
250 floats and storing the compressed binary in the DB BLOB field. I also
though about breaking the values into an sbyte and a byte like this:
-5.29
represented as:
sbyte l = -5;
byte r = 29;
This would save me to bytes from using a float. If I then compressed this
"byte data" I could save even more space.
Anyway, I have never done any of this before and wanted to invite you guys
to offer any suggestions or past experiences you might of had with doing
something like this.
As you can see, I'm not real sure what I'm doing ;0)
Thanks for reading,
Steve
.
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