Least Square Line

[Mikf]

hi!
i'm writing a patch to use the LSL (least square line) of rrdtool ( http://oss.oetiker.ch/rrdtool/doc/rrdgraph_rpn.en.html )
Only for rrdtool version 1.2.x

I have created 4 new 'Special Data Source' for CDEF function :

• CURRENT_DS_LSLSLOPE : return the LSLSCOPE variable of rrdtool
  CURRENT_DS_LSLINT : return the LSLINT variable of rrdtool
  CURRENT_DS_LSLCORREL : return the LSLCORREL variable of rrdtool (not tested)
  CURRENT_DS_LSLFUNCTION : return the y=ax+b function (y=LSLSCOPE * x + LSLINT)

To use the LSL function, VDEF definitions must be created in the rrdgraph command. This is what my path is doing.


CURRENT_DS_LSLFUNCTION can be used alone in a CDEF function, this will trace the line, but if the datasource is used with a CDEF function (like 'turn byte into bits'), you may create a CDEF with CURRENT_DS_LSLFUNCTION and the same operation.

exemple : if your graph is using "Turn Bytes into bits"
"Turn Bytes into bits" cdef=CURRENT_DATA_SOURCE,8,*
then , to trace the LSL line, create a cdef function like this:
"LSL Turn Bytes into bits" cdef=CURRENT_DS_LSLFUNCTION,8,*

note: LSL's functions cannot be used alone, in a CDEF function, a data_source must be present.
(exepted the CURRENT_DS_LSLFUNCTION that include automaticaly a datasource and POP it (remove from the stack in cdef))

to display the percent of evolution of the graphed period, create a cdef function
cdef=CURRENT_DATA_SOURCE,POP,CURRENT_DS_LSLSLOPE,COUNT,*,CURRENT_DS_LSLINT,0,LE,0.1,CURRENT_DS_LSLINT,IF,/,100,*
and use a GPRINT with "LAST" as Consolidation Function


Patch is for cacti 0.8.6j without official patch
copy the patch file in cacti directory
be in cacti directory to apply the patch
if you want to test before :
patch -p1 -N --dry-run < lsl.patch

patch:
patch -p1 -N < lsl.patch

-
Jerome

Sorry for my english

EDIT: version 1.1 : trace line even if data value is unknown (cf picture 2)
EDIT : version 1.2: simplify function

[chrisgapske]

Have you tested this with 0.8.7 beta 4/SVN ?


Would be nice to have added to cacti base.

[rony]

VDEF will be coming, not in 0.8.7. But will be in an upcoming release.

[Mikf]

Have you tested this with 0.8.7 beta 4/SVN ?

No, only with 0.8.6j

VDEF will be coming, not in 0.8.7. But will be in an upcoming release.

[samcpeak]

I’ve been looking for a way to make a trend line that changes based on the time frame that is shown. Someone from my company had previously used your patch to accomplish this, but they have left the company. I’m trying to install this patch on my server, but I am having some trouble.

I copied uploaded the patch into my cacti directory (/var/www/html) and then did

[root@localhost emsadmin]# cd /var/www/html
[root@localhost html]# patch -p1 -N <lsl-1.2.patch
can't find file to patch at input line 4
Perhaps you used the wrong -p or --strip option?
The text leading up to this was:
--------------------------
|diff -ruBbd cacti-0.8.6j.test/include/config_arrays.php cacti-0.8.6j-patch/include/config_arrays.php
|--- cacti-0.8.6j.test/include/config_arrays.php 2007-10-17 20:49:36.000000000 +0200
|+++ cacti-0.8.6j-patch/include/config_arrays.php 2007-10-17 20:51:32.000000000 +0200
--------------------------
File to patch:

And then it waited for a response at ‘File to patch:’ I’m not sure what to put there.

Maybe I am doing it wrong. Could you explain to me how to correctly patch your file?

Btw I'm using v0.8.7g.

Thank you!

[noname]

That patch is for quite older version (0.8.6j) of Cacti. There isn't "include/config_arrays.php" now.

I tried to create new one (but nothing changed).
This patch is for Cacti 0.8.7g with official patch.

lsl-1.2_087g.patch

for 0.8.7g with official patch

(4.35 KiB) Downloaded 429 times

(You'll see "Hunk ..." if you have installed PA. But probably it will succeed to apply.)

And I followed as Mikf mentioned, make a graph template.
Here is a example.

(sample)cacti_graph_template_interface_traffic_with_lsl.zip

sample graph template: "Interface - Traffic (bits/sec) with LSL"

(3.36 KiB) Downloaded 353 times

Import results:

Graph:


They say Least Squares is elementary method in Classical Econometrics,
but anyway it is interesting when drawing graph...

[noname]

P.S.
This modification uses LSLSLOPE, LSLINT, and LSLCORREL on VDEF= statement as Mikf mentioned at the above.
I'm guessing, these RRDtool options (and others?) will be able to use in 088 release...

[gandalf]

P.S.
This modification uses LSLSLOPE, LSLINT, and LSLCORREL on VDEF= statement as Mikf mentioned at the above.
I'm guessing, these RRDtool options (and others?) will be able to use in 088 release...

Correct
R.

[gandalf]

Function has been postponed to 089
R.

[kdmillerii]

I upgraded from 087g to 088a and this patch no longer works. Is someone working on a 088a patch?

What is the timeframe of 089? I saw on the roadmap that 1.0.0 is planned for a few months. Is that still correct?

What I'm trying to do is take a daily 95th percentile and LSL that over time.

[gandalf]

VDEF is already part of 089. This is currently in alpha state, which means, that bug hunting is in progress now.
Here's the deal:
In case you help testing this feature with 089, I will do the coding for this feature, if sth is still missing.
In case you agree, please download 089 code from SVN to a test machine. Open a new thread for your issues in the announcement forum
R.

[artms]

Here is the patch for cacti 0.8.8a. Everything else is the same as Mikf wrote...

[artiflo]

Thanks for the patch.