131 lines
3.3 KiB
TeX
131 lines
3.3 KiB
TeX
\documentclass[a4paper]{article}
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\usepackage{pst-plot}
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\pagestyle{empty}
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\begin{document}
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\SpecialCoor% importanmt for all examples
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\begin{pspicture}(-6,-6)(6,6)
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\psaxes{<->}(0,0)(-6,-6)(6,6)
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\psset{arrows=->}
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\multido{\ia=-5+1}{11}{%
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\multido{\ib=-5+1}{11}{%
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\pstVerb{/x \ia\space def
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/y \ib\space def
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y 0 eq
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{/ValueTempA 0 def
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/ValueTempB 0.5 def}
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{/ValueTempZ 2 1 x x mul y y mul div add sqrt mul def
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/ValueTempA 1 ValueTempZ div def
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/ValueTempB x y ValueTempZ mul div def}
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ifelse}
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\psline(! x ValueTempA sub y ValueTempB sub)
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(! x ValueTempA add y ValueTempB add)}}
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\end{pspicture}
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\begin{pspicture}(-6,-6)(6,6)
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\psaxes{<->}(0,0)(-6,-6)(6,6)
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\psset{arrows=->}
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\multido{\ia=-5+1}{11}{%
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\multido{\ib=-5+1}{11}{%
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\pstVerb{/x \ia\space def
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/y \ib\space def
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y 0 eq
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{/ValueTempA 0 def
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/ValueTempB 0.5 def}
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{/ValueTempZ 2 1 x x mul y y mul div add sqrt mul def
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/ValueTempA 1 ValueTempZ div def
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/ValueTempB x neg y ValueTempZ mul div def}
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ifelse}
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\psline(! x ValueTempA sub y ValueTempB sub)
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(! x ValueTempA add y ValueTempB add)}}
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\end{pspicture}
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% From Michael Sharpe
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\def\transl#1#2{%
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#1\space 72 2.54 div mul #2\space 72 2.54 div mul translate 0 0 moveto}
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\newif\ifnotbothz
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\begin{pspicture}(-6,-6)(6,6)
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\psaxes{<->}(0,0)(-6,-6)(6,6)
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\multido{\n=-5+1}{11}{%
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\multido{\N=-5+1}{11}{%
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\notbothztrue
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\ifnum\N=0
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\ifnum\n=0
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\notbothzfalse
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\fi
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\fi
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\ifnotbothz
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\psdot(0,0)
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\pstverb{\transl{\n}{\N}\space
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%next line gives a direction vector (y=\n,x=\N)
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\n\space \N\space
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atan rotate -9 0 moveto 18 0 rlineto stroke}
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\fi}}
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\end{pspicture}
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\begin{pspicture}(-6,-6)(6,6)
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\psaxes{<->}(0,0)(-6,-6)(6,6)
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\multido{\n=-5+1}{11}{%
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\multido{\N=-5+1}{11}{%
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\notbothztrue
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\ifnum\N=0
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\ifnum\n=0
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\notbothzfalse
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\fi
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\fi
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\ifnotbothz
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\psdot(0,0)
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\pstverb{\transl{\n}{\N}\space
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%next line gives a direction vector (y=-\n,x=\N)
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\n\space neg \N\space
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atan rotate -9 0 moveto 18 0 rlineto stroke}
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\fi}}
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\end{pspicture}
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\clearpage
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Another solution for a vector field:
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\def\drawseg#1#2{%
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\pscustom{%
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\translate(#1,#2)
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\rotate{(\dirseg{#1}{#2})} % Vector in direction of field at x=#1,y=#2
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\psline(-.25,0)(.25,0)}}
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\def\dirseg#1#2{-#2,#1} % Default direction field ($y'=-x/y$)
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\begin{pspicture}(-6,-6)(6,6)
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\psaxes{<->}(0,0)(-6,-6)(6,6)
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\multido{\n=-5+1}{11}{%
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\multido{\N=-5+1}{11}{%
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\ifnum\N=0
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\ifnum\n=0
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\else
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\drawseg{\n}{\N}
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\fi
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\else
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\drawseg{\n}{\N}
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\fi}}
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\end{pspicture}
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\def\dirseg#1#2{#2,#1} % Direction field example ($y'=x/y$)
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\begin{pspicture}(-6,-6)(6,6)
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\psaxes{<->}(0,0)(-6,-6)(6,6)
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\psset{arrows=->}
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\multido{\n=-5+1}{11}{%
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\multido{\N=-5+1}{11}{%
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\ifnum\N=0
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\ifnum\n=0
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\else
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\drawseg{\n}{\N}
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\fi
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\else
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\drawseg{\n}{\N}
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\fi}}
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\end{pspicture}
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\end{document}
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