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diff --git a/doc/rrdgraph_rpn.1 b/doc/rrdgraph_rpn.1
index 9feb50cd89df604b41537af903eb6b8c73855413..9c600720fd5847476e80e82f5cf7cb986ea959ad 100644 (file)
--- a/doc/rrdgraph_rpn.1
+++ b/doc/rrdgraph_rpn.1
-.\" Automatically generated by Pod::Man v1.37, Pod::Parser v1.32
+.\" Automatically generated by Pod::Man 2.25 (Pod::Simple 3.16)
.\"
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.\" ========================================================================
-.de Sh \" Subsection heading
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+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\"
.\" If the F register is turned on, we'll generate index entries on stderr for
-.\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index
+.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
.\" entries marked with X<> in POD. Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
-.if \nF \{\
+.ie \nF \{\
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-.\" way too many mistakes in technical documents.
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-.if n .na
+.el \{\
+. de IX
+..
+.\}
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.IX Title "RRDGRAPH_RPN 1"
-.TH RRDGRAPH_RPN 1 "2008-03-15" "1.3.0" "rrdtool"
+.TH RRDGRAPH_RPN 1 "2013-05-23" "1.4.8" "rrdtool"
+.\" For nroff, turn off justification. Always turn off hyphenation; it makes
+.\" way too many mistakes in technical documents.
+.if n .ad l
+.nh
.SH "NAME"
rrdgraph_rpn \- About RPN Math in rrdtool graph
.SH "SYNOPSIS"
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
If you have ever used a traditional \s-1HP\s0 calculator you already know
-\&\fB\s-1RPN\s0\fR. The idea behind \fB\s-1RPN\s0\fR is that you have a stack and push
+\&\fB\s-1RPN\s0\fR (Reverse Polish Notation).
+The idea behind \fB\s-1RPN\s0\fR is that you have a stack and push
your data onto this stack. Whenever you execute an operation, it
takes as many elements from the stack as needed. Pushing is done
implicitly, so whenever you specify a number or a variable, it gets
.Sp
Pop two elements from the stack, compare them for the selected condition
and return 1 for true or 0 for false. Comparing an \fIunknown\fR or an
-\&\fIinfinite\fR value will always result in 0 (false).
+\&\fIinfinite\fR value will result in \fIunknown\fR returned ... which will also be
+treated as false by the \fB\s-1IF\s0\fR call.
.Sp
\&\fB\s-1UN\s0, \s-1ISINF\s0\fR
.Sp
.Sp
Example: \f(CW\*(C`A,B,C,IF\*(C'\fR should be read as \f(CW\*(C`if (A) then (B) else (C)\*(C'\fR
.Sp
-\&\&
+
.IP "Comparing values" 4
.IX Item "Comparing values"
\&\fB\s-1MIN\s0, \s-1MAX\s0\fR
Example: \f(CW\*(C`CDEF:a=alpha,0,100,LIMIT\*(C'\fR will return \fIunknown\fR if
alpha is lower than 0 or if it is higher than 100.
.Sp
-\&\&
+
.IP "Arithmetics" 4
.IX Item "Arithmetics"
\&\fB+, \-, *, /, %\fR
\& <\-\-\-\-\-\-\-\-\-\-\-\-\-\-\->
\& delay t2
\& <\-\-\-\-\-\-\-\-\-\-\-\-\-\-\->
-.Ve
-.Sp
-.Vb 3
+\&
+\&
\& Value at sample (t0) will be the average between (t0\-delay) and (t0)
\& Value at sample (t1) will be the average between (t1\-delay) and (t1)
\& Value at sample (t2) will be the average between (t2\-delay) and (t2)
.Ve
.Sp
-\&\s-1TRENDNAN\s0 is \- in contrast to \s-1TREND\s0 \- NAN\-safe. If you use \s-1TREND\s0 and one
+\&\s-1TRENDNAN\s0 is \- in contrast to \s-1TREND\s0 \- NAN-safe. If you use \s-1TREND\s0 and one
source value is \s-1NAN\s0 the complete sliding window is affected. The \s-1TRENDNAN\s0
operation ignores all NAN-values in a sliding window and computes the
average of the remaining values.
+.Sp
+\&\fB\s-1PREDICT\s0, \s-1PREDICTSIGMA\s0\fR
+.Sp
+Create a \*(L"sliding window\*(R" average/sigma of another data series, that also
+shifts the data series by given amounts of of time as well
+.Sp
+Usage \- explicit stating shifts:
+CDEF:predict=<shift n>,...,<shift 1>,n,<window>,x,PREDICT
+CDEF:sigma=<shift n>,...,<shift 1>,n,<window>,x,PREDICTSIGMA
+.Sp
+Usage \- shifts defined as a base shift and a number of time this is applied
+CDEF:predict=<shift multiplier>,\-n,<window>,x,PREDICT
+CDEF:sigma=<shift multiplier>,\-n,<window>,x,PREDICTSIGMA
+.Sp
+Example:
+CDEF:predict=172800,86400,2,1800,x,PREDICT
+.Sp
+This will create a half-hour (1800 second) sliding window average/sigma of x, that
+average is essentially computed as shown here:
+.Sp
+.Vb 10
+\& +\-\-\-!\-\-\-!\-\-\-!\-\-\-!\-\-\-!\-\-\-!\-\-\-!\-\-\-!\-\-\-!\-\-\-!\-\-\-!\-\-\-!\-\-\-!\-\-\-!\-\-\-!\-\-\-!\-\-\-!\-\-\->
+\& now
+\& shift 1 t0
+\& <\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\->
+\& window
+\& <\-\-\-\-\-\-\-\-\-\-\-\-\-\-\->
+\& shift 2
+\& <\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\->
+\& window
+\& <\-\-\-\-\-\-\-\-\-\-\-\-\-\-\->
+\& shift 1 t1
+\& <\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\->
+\& window
+\& <\-\-\-\-\-\-\-\-\-\-\-\-\-\-\->
+\& shift 2
+\& <\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\->
+\& window
+\& <\-\-\-\-\-\-\-\-\-\-\-\-\-\-\->
+\&
+\& Value at sample (t0) will be the average between (t0\-shift1\-window) and (t0\-shift1)
+\& and between (t0\-shift2\-window) and (t0\-shift2)
+\& Value at sample (t1) will be the average between (t1\-shift1\-window) and (t1\-shift1)
+\& and between (t1\-shift2\-window) and (t1\-shift2)
+.Ve
+.Sp
+The function is by design NAN-safe.
+This also allows for extrapolation into the future (say a few days)
+\&\- you may need to define the data series whit the optional start= parameter, so that
+the source data series has enough data to provide prediction also at the beginning of a graph...
+.Sp
+Here an example, that will create a 10 day graph that also shows the
+prediction 3 days into the future with its uncertainty value (as defined by avg+\-4*sigma)
+This also shows if the prediction is exceeded at a certain point.
+.Sp
+rrdtool graph image.png \-\-imgformat=PNG \e
+ \-\-start=\-7days \-\-end=+3days \-\-width=1000 \-\-height=200 \-\-alt\-autoscale\-max \e
+ DEF:value=value.rrd:value:AVERAGE:start=\-14days \e
+ LINE1:value#ff0000:value \e
+ CDEF:predict=86400,\-7,1800,value,PREDICT \e
+ CDEF:sigma=86400,\-7,1800,value,PREDICTSIGMA \e
+ CDEF:upper=predict,sigma,3,*,+ \e
+ CDEF:lower=predict,sigma,3,*,\- \e
+ LINE1:predict#00ff00:prediction \e
+ LINE1:upper#0000ff:upper\e certainty\e limit \e
+ LINE1:lower#0000ff:lower\e certainty\e limit \e
+ CDEF:exceeds=value,UN,0,value,lower,upper,LIMIT,UN,IF \e
+ TICK:exceeds#aa000080:1
+.Sp
+Note: Experience has shown that a factor between 3 and 5 to scale sigma is a good
+discriminator to detect abnormal behavior. This obviously depends also on the type
+of data and how \*(L"noisy\*(R" the data series is.
+.Sp
+This prediction can only be used for short term extrapolations \- say a few days into the future\-
.IP "Special values" 4
.IX Item "Special values"
\&\fB\s-1UNKN\s0\fR
.IP "Time" 4
.IX Item "Time"
Time inside RRDtool is measured in seconds since the epoch. The
-epoch is defined to be \f(CW\*(C`Thu\ Jan\ 1\ 00:00:00\ UTC\ 1970\*(C'\fR.
+epoch is defined to be \f(CW\*(C`Thu\ Jan\ \ 1\ 00:00:00\ UTC\ 1970\*(C'\fR.
.Sp
\&\fB\s-1NOW\s0\fR
.Sp
Duplicate the top element, remove the top element, exchange the two
top elements.
.Sp
-\&\&
+
.SH "VARIABLES"
.IX Header "VARIABLES"
These operators work only on \fB\s-1VDEF\s0\fR statements. Note that currently \s-1ONLY\s0 these work for \fB\s-1VDEF\s0\fR.
Example: \f(CW\*(C`VDEF:stdev=mydata,STDEV\*(C'\fR
.IP "\s-1LAST\s0, \s-1FIRST\s0" 4
.IX Item "LAST, FIRST"
-Return the last/first value including its time. The time for
-\&\s-1FIRST\s0 is actually the start of the corresponding interval, whereas
-\&\s-1LAST\s0 returns the end of the corresponding interval.
+Return the last/first non-nan or infinite value for the selected data
+stream, including its timestamp.
.Sp
Example: \f(CW\*(C`VDEF:first=mydata,FIRST\*(C'\fR
.IP "\s-1TOTAL\s0" 4
.IX Item "TOTAL"
Returns the rate from each defined time slot multiplied with the
-step size. This can, for instance, return total bytes transfered
+step size. This can, for instance, return total bytes transferred
when you have logged bytes per second. The time component returns
the number of seconds.
.Sp
Example: \f(CW\*(C`VDEF:total=mydata,TOTAL\*(C'\fR
-.IP "\s-1PERCENT\s0" 4
-.IX Item "PERCENT"
+.IP "\s-1PERCENT\s0, \s-1PERCENTNAN\s0" 4
+.IX Item "PERCENT, PERCENTNAN"
This should follow a \fB\s-1DEF\s0\fR or \fB\s-1CDEF\s0\fR \fIvname\fR. The \fIvname\fR is popped,
another number is popped which is a certain percentage (0..100). The
data set is then sorted and the value returned is chosen such that
\&\fIpercentage\fR percent of the values is lower or equal than the result.
+For \s-1PERCENTNAN\s0 \fIUnknown\fR values are ignored, but for \s-1PERCENT\s0
\&\fIUnknown\fR values are considered lower than any finite number for this
purpose so if this operator returns an \fIunknown\fR you have quite a lot
of them in your data. \fBInf\fRinite numbers are lesser, or more, than the
(NaN < \-INF < finite values < \s-1INF\s0)
.Sp
Example: \f(CW\*(C`VDEF:perc95=mydata,95,PERCENT\*(C'\fR
+ \f(CW\*(C`VDEF:percnan95=mydata,95,PERCENTNAN\*(C'\fR
.IP "\s-1LSLSLOPE\s0, \s-1LSLINT\s0, \s-1LSLCORREL\s0" 4
.IX Item "LSLSLOPE, LSLINT, LSLCORREL"
Return the parameters for a \fBL\fReast \fBS\fRquares \fBL\fRine \fI(y = mx +b)\fR
y\-intercept \fI(b)\fR, which happens also to be the first data point on the
graph. \s-1LSLCORREL\s0 is the Correlation Coefficient (also know as Pearson's
Product Moment Correlation Coefficient). It will range from 0 to +/\-1
-and represents the quality of fit for the approximation.
+and represents the quality of fit for the approximation.
.Sp
Example: \f(CW\*(C`VDEF:slope=mydata,LSLSLOPE\*(C'\fR
.SH "SEE ALSO"
.IX Header "AUTHOR"
Program by Tobias Oetiker <tobi@oetiker.ch>
.PP
-This manual page by Alex van den Bogaerdt <alex@ergens.op.het.net>
+This manual page by Alex van den Bogaerdt <alex@vandenbogaerdt.nl>
+with corrections and/or additions by several people