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Is it possible to mark the intersection point of two tkz-fct functions and print it's coordinates?
For example in this case:
\documentclass{article}
\usepackage{tkz-fct}
\begin{document}
\begin{tikzpicture}
\tkzInit[ymax=15,xmax=4,ystep=5]
\tkzAxeXY
\tkzFct[color=red,domain=0:4]{2*x**2+5}
\tkzFct[color=blue,domain=0:4]{-x**3+15}
\end{tikzpicture}
\end{document}
No there is nothing specific in tkz-fct. You need to use TikZ to do that. With simple functions like in your example, you can use fp.
I think when you have complex functions , it's better to get the intersection with a real mathematics soft.
Actually tkz-fct works only with gnuplot and perhaps it's possible to use tables created by gnuplot to find an approximation of the intersection.
Now perhaps with lua, it's possible to find a fine method.
Update
But I find a solution ! I modified my package but I don't know if there are bad effects:
I used id for 'name path' and I modified \def\tkz@fct
\documentclass{article}
\usepackage{tkz-fct}
\usetikzlibrary{%
arrows,
calc,intersections
}
\makeatletter
\def\tkz@fct[#1]#2{%
\pgfkeys{/tkzfct/.cd,
domain = \tkz@dmin:\tkz@dmax,
samples = 200,
fp = true,
id = tkzfct}
\pgfqkeys{/tkzfct}{#1}%
\iftkz@init@NO%
\FPdiv{\tkz@x@delta}{\tkz@init@xorigine}{\tkz@init@xstep}%
\FPdiv{\tkz@y@delta}{\tkz@init@yorigine}{\tkz@init@ystep}%
\else
\FPset{\tkz@x@delta}{0}%
\FPset{\tkz@y@delta}{0}%
\fi%
% stockage
\advance\tkz@tkzf@fct by 1 %
\FPdiv\tkz@ba{\tkz@min}{\tkz@init@xstep}%
\FPdiv\tkz@bb{\tkz@max}{\tkz@init@xstep}%
\def\x{(x*\tkz@init@xstep)}%
\expandafter\edef\csname tkzFctgnu\@alph\tkz@tkzf@fct \endcsname{#2}%
\expandafter\edef\csname tkzFctgnuLast\endcsname{#2}
\clip (\tkz@xa,\tkz@ya) rectangle (\tkz@xb,\tkz@yb);
\draw[name path =\tkz@fct@id,xshift = -\tkz@x@delta cm,yshift = -\tkz@y@delta cm,/tkzfct/.cd,#1 ]%
plot[id=\tkz@fct@id,domain= \tkz@ba:\tkz@bb,samples = \tkz@fct@samples]%
function{(#2)/\tkz@init@ystep};%
%\end{scope}
\let\tkz@tmp@xstep\tkz@init@xstep
\def\tkz@init@xstep{1}
\iftkz@fp%
\ReplaceSubStrings{\tkz@tempa}{#2}{log}{ln}
\ReplaceSubStrings{\tkz@tempb}{\tkz@tempa}{**}{^}
\ReplaceSubStrings{\tkz@tempa}{\tkz@tempb}{\x}{x}
\ReplaceSubStrings{\tkz@tempb}{\tkz@tempa}{asin}{arcsin}
\ReplaceSubStrings{\tkz@tempa}{\tkz@tempb}{acos}{arccos}
\ReplaceSubStrings{\tkz@tempb}{\tkz@tempa}{atan}{arctan}
\expandafter\edef\csname tkzFct\@alph\tkz@tkzf@fct\endcsname{\tkz@tempb}%
\expandafter\edef\csname tkzFctLast\endcsname{\tkz@tempb}%
\fi
\let\tkz@init@xstep\tkz@tmp@xstep
\catcode`\:=\tkzTWOPTCode\relax
}%
\makeatother
\begin{document}
\begin{tikzpicture}
\tkzInit[ymax=15,xmax=4,ystep=5]
\tkzAxeXY
\tkzFct[id=f,color=red,domain=0:4]{2*x**2+5}
\tkzFct[id=g,color=blue,domain=0:4]{-x**3+15}
\fill [red, opacity=0.5, name intersections={of=f and g}]
(intersection-1) circle (2pt) node {};
\end{tikzpicture}
\end{document}
todo
With some calculations you can get the coordinate system values like Jakes writes.
I need to create a specific macro because sometimes the system is translate and the units can change with xstep and ystep.
Here a solution before a new macro
\begin{document}
\begin{tikzpicture}
\tkzInit[ymax=15,xmax=4,ystep=5]
\tkzAxeXY
\tkzFct[id=f,color=red,domain=0:4]{2*x**2+5}
\tkzFct[id=g,color=blue,domain=0:4]{-x**3+15}
\makeatletter
\draw [name intersections={of=f and g, by=fxg}] let \p1=(fxg) in
(fxg) circle (1pt) \pgfextra{\pgfmathsetmacro\xc{\x1/28.45}\pgfmathsetmacro\yc{\y1/28.45*\tkz@init@ystep}} node [right,align=left] {a=\xc\\ b=\yc};
\end{tikzpicture}
name plot/.style={every path/.style={name path global=#1}} because you can avoid to add a big piece of code. Another possibility is to modify directly the package but it's preferable to wait a new version.
– Alain Matthes
Apr 30 '12 at 22:24
every path/.style={name path global=A}
– Alain Matthes
May 1 '12 at 20:19
It is possible if you use TikZ directly to plot and combine it with the intersections library.
\documentclass{article}
\usepackage{tkz-fct}
\usetikzlibrary{intersections}
\tikzset{
name plot/.style={every path/.style={name path global=#1}}
}
\begin{document}
\begin{tikzpicture}
\tkzInit[ymax=15,xmax=4,ystep=5]
\tkzAxeXY
%
\tkzFct[name plot=A,color=red,domain=0:4]{2*x**2+5}
%
\tkzFct[name plot=B,color=blue,domain=0:4]{-x**3+15}
%
\draw [name intersections={of=A and B, by=AxB}] (AxB) circle (2pt);
\end{tikzpicture}
\end{document}
With the following line you can read out the absolute coordinates of the intersection point as it is placed in the resulting picture. With some calculations you can get the coordinate system values I guess …
\draw [name intersections={of=A and B, by=AxB}] let \p1=(AxB) in
(AxB) circle (1pt) node [right] {\x1,\y1};
File list
*File List*
article.cls 2007/10/19 v1.4h Standard LaTeX document class
size10.clo 2007/10/19 v1.4h Standard LaTeX file (size option)
tkz-fct.sty 2011/06/01 1.16 c function
tkz-base.sty 2011/06/01 1.16 c tkz-base
etex.sty 1998/03/26 v2.0 eTeX basic definition package (PEB)
tikz.sty 2010/10/13 v2.10 (rcs-revision 1.76)
pgf.sty 2008/01/15 v2.10 (rcs-revision 1.12)
pgfrcs.sty 2010/10/25 v2.10 (rcs-revision 1.24)
everyshi.sty 2001/05/15 v3.00 EveryShipout Package (MS)
pgfrcs.code.tex
pgfcore.sty 2010/04/11 v2.10 (rcs-revision 1.7)
graphicx.sty 1999/02/16 v1.0f Enhanced LaTeX Graphics (DPC,SPQR)
keyval.sty 1999/03/16 v1.13 key=value parser (DPC)
graphics.sty 2009/02/05 v1.0o Standard LaTeX Graphics (DPC,SPQR)
trig.sty 1999/03/16 v1.09 sin cos tan (DPC)
graphics.cfg 2010/04/23 v1.9 graphics configuration of TeX Live
pdftex.def 2011/05/27 v0.06d Graphics/color for pdfTeX
infwarerr.sty 2010/04/08 v1.3 Providing info/warning/message (HO)
ltxcmds.sty 2011/04/18 v1.20 LaTeX kernel commands for general use (HO)
pgfsys.sty 2010/06/30 v2.10 (rcs-revision 1.37)
pgfsys.code.tex
pgfsyssoftpath.code.tex 2008/07/18 (rcs-revision 1.7)
pgfsysprotocol.code.tex 2006/10/16 (rcs-revision 1.4)
xcolor.sty 2007/01/21 v2.11 LaTeX color extensions (UK)
color.cfg 2007/01/18 v1.5 color configuration of teTeX/TeXLive
pgfcore.code.tex
pgfcomp-version-0-65.sty 2007/07/03 v2.10 (rcs-revision 1.7)
pgfcomp-version-1-18.sty 2007/07/23 v2.10 (rcs-revision 1.1)
pgffor.sty 2010/03/23 v2.10 (rcs-revision 1.18)
pgfkeys.sty
pgfkeys.code.tex
pgffor.code.tex
tikz.code.tex
numprint.sty 2008/02/17 v1.38 Print numbers (HH)
array.sty 2008/09/09 v2.4c Tabular extension package (FMi)
fp.sty 1995/04/02
defpattern.sty 1994/10/12
fp-basic.sty 1996/05/13
fp-addons.sty 1995/03/15
fp-snap.sty 1995/04/05
fp-exp.sty 1995/04/03
fp-trigo.sty 1995/04/14
fp-pas.sty 1994/08/29
fp-random.sty 1995/02/23
fp-eqn.sty 1995/04/03
fp-upn.sty 1996/10/21
fp-eval.sty 1995/04/03
tkz-tools-utilities.tex
tkz-tools-arith.tex
tkz-tools-base.tex
tkz-tools-misc.tex
tkz-tools-math.tex
tkz-obj-points.tex
tkz-obj-segments.tex
tkz-obj-marks.tex
supp-pdf.mkii
pdftexcmds.sty 2011/04/22 v0.16 Utilities of pdfTeX for LuaTeX (HO)
ifluatex.sty 2010/03/01 v1.3 Provides the ifluatex switch (HO)
ifpdf.sty 2011/01/30 v2.3 Provides the ifpdf switch (HO)
epstopdf-base.sty 2010/02/09 v2.5 Base part for package epstopdf
grfext.sty 2010/08/19 v1.1 Managing graphics extensions (HO)
kvdefinekeys.sty 2011/04/07 v1.3 Defining keys (HO)
kvoptions.sty 2010/12/23 v3.10 Keyval support for LaTeX options (HO)
kvsetkeys.sty 2011/04/07 v1.13 Key value parser (HO)
etexcmds.sty 2011/02/16 v1.5 Prefix for e-TeX command names (HO)
epstopdf-sys.cfg 2010/07/13 v1.3 Configuration of (r)epstopdf for TeX Live
***********
name path to \tkzFct? I tried it but it doesn’t work – I guess the options of \tkzFct are send to plot and not to \draw or something like that …
– Tobi
Apr 30 '12 at 21:30
every path/.style={name path global=A} in the options of the \tkzFct.
– Jake
Apr 30 '12 at 21:35
global with name path globaland it's why I remove a scope but perhaps I can remove it without problem.
– Alain Matthes
Apr 30 '12 at 22:26
Package tikz Error: I do not know the path named A'`
– student
May 1 '12 at 19:52
