Package tikz error giving up on this path did you forget a semicolon

The general syntax of TikZ is to enter the stuff you want to be drawn in a format matching something like:

command [ options ] ( location ) { stuff } ;

Where almost everything might not be needed. Just the command (e.g. draw) and the trailing ; to limit the scope of the command, are important. You forgot that ; in the last line of your tikzpicture and therefore get this error. And you forgot a at beginning of draw in the unidirectionAssociation renaming block.
Use draw[umlcd style, ->] (#1) -- (#4) instead of draw[umlcd style, ->] (#1) -- (#4)

The following compiles:

documentclass{standalone}
usepackage{pgf-umlcd}

renewcommand{unidirectionalAssociation}[4]
{
  draw[umlcd style, ->] (#1) -- (#4)% <------
  node[near end, auto]{#2}
  node[near end, auto,swap]{#3};
}

begin{document}
begin{tikzpicture}

  begin{abstractclass}[text width = 6cm]{FileStore}{0,0}
    attribute{$sim$ com.alhelal.textpad}
    operation{+ orderFile(file : File) : EditableFile} 
    operation[0]{# createFile(file : File) : EditableFile}
  end{abstractclass}

  begin{class}[text width = 6cm,anchor = west,xshift = 5cm]{ProgrammFileFactory}{FileStore.east}
    inherit{FileStore}
    attribute{$sim$ com.alhelal.textpad}
    operation{+ orderFile(file : File) : EditableFile} 
  end{class}

  begin{class}[text width = 11cm, yshift = -2cm]{EditableFile}{ProgrammFileFactory.south}
    attribute{$sim$ com.alhelal.textpad}
    attribute{+ languageBehavior : LanguageBehavior} 
    operation{+ options : Options} 
    operation{+ getCodeAreaFromTab(tb : Tab) : CodeArea} 
    operation{+ saveFile(fileTabArrayList : ArrayList$<$FileTab$>$, option : Options)}
    operation{+ printFile(node : Node)}
    operation{+ toggleLineNumber(cd : CodeArea)}
    operation{+ setLanguageBehavior(langBehavior : LanguageBehavior)}
    operation{+ performRunCode(file : File)}
    operation{+ performBuildCode(file : File)}
    operation{+ performSetHighlightableText()}
    operation{+ performSetAutocompletableText()}
  end{class}

  begin{class}[text width = 3.5cm,anchor=north east,yshift = -2cm, xshift=-6cm]{TextFile}{EditableFile.south west}
    inherit{EditableFile}
    attribute{$sim$ com.alhelal.textpad}
  end{class}

  begin{class}[text width = 3.5cm,anchor=north east,yshift = -2cm, xshift = -1.5cm]{CFile}{EditableFile.south west}
    inherit{EditableFile}
    attribute{$sim$ com.alhelal.textpad}
    attribute{-path : String}
  end{class}

  begin{class}[text width=3.5cm,anchor=north west,yshift = -2cm,xshift=-3cm]{CplusFile}{EditableFile.south}
    inherit{EditableFile}
    attribute{$sim$ com.alhelal.textpad}
  end{class}

  begin{class}[text width  = 3.5cm, anchor = north west, yshift = -2cm, xshift = -4cm]{JavaFile}{EditableFile.south east}
    inherit{EditableFile}
    attribute{$sim$ com.alhelal.textpad}
  end{class}

  begin{class}[text width = 3.5cm,yshift = -2cm,xshift = 1cm]{PythonFile}{EditableFile.south east}
    inherit{EditableFile}
    attribute{$sim$ com.alhelal.textpad}
  end{class}

  begin{class}[text width = 3.5cm, anchor = north west, yshift =-2cm,xshift = 5cm]{LaTeXFile}{EditableFile.south east}
    inherit{EditableFile}
    attribute{$sim$ com.alhelal.textpad}
  end{class}
  unidirectionalAssociation{ProgrammFileFactory}{}{$<<$instantiate$>>$}{EditableFile}
  node [above=3mm] at (current bounding box.north) {Factory Method Pattern};% <-------
end{tikzpicture}
end{document}

I marked the lines I changed with % <-------.

EDIT: I’ve updated the above code to include the correct redefinition of unidirectionalAssociation thanks to the clarifications provided by @TorbjørnT.

Thank you for the response. I am a beginner in LATEX. I have learnt just a few things and trying it by just typing a sample article. In my article, I am trying to draw a block diagram after text in a subsection. I am trying it using tikz package.
The script is shared below. I am running this script with INTERNET OFF, getting the errors as :

! Package pgf Error: No shape named `N-point FFT’ is known.See the pgf package documentation for explanation.Type H <return> for immediate help….

! Package tikz Error: Giving up on this path. Did you forget a semicolon?.See the tikz package documentation for explanation.Type H <return> for immediate help…. end{tikzpicture}

! Undefined control sequence.<argument> pgf@baseline end{tikzpicture}

With the INTERNET ON, Neither Error nor Output is being displayed.

I am looking for some assistance please.

Script:

documentclass[10pt,onecolumn,a4paper]{article}
linespread{1.5}
title{PAPR reduction and non-linearity alleviation using hybrid of precoding and companding in a visible light communication (VLC) system}
%author{Nishant Sharan\S.K Ghorai}
usepackage{amssymb,amsmath}
usepackage{graphicx} % dvips destroys the tikzpicture to a mess
usepackage{tikz}
usetikzlibrary{shapes.geometric,arrows}
tikzstyle{startstop} = [rectangle, rounded corners, text centered, draw=black, fill=blue!10]
tikzstyle{process} = [rectangle, minimum width=2cm, minimum height=1cm, text centered, draw=black, fill=orange!10]
tikzstyle{decision} = [diamond, aspect=3, minimum width=3cm, minimum height=1cm, text centered, draw=black, fill=red!10]
% define arrow style
tikzstyle{compute} = [rectangle, minimum width=2cm, minimum height=1cm, text centered, draw=black, fill=green!10]
tikzstyle{estimate} = [rectangle, rounded corners, minimum width=2cm, minimum height=1cm, text centered, draw=black, fill=yellow!10]
tikzstyle{arrow} = [thick,->,>=stealth]
tikzstyle{block}=[draw,rectangle,node distance=8em]
begin {document}
%begin{flushleft}
maketitle
section*{Abstract}A hybrid technique using a precoder and a $mu$ law compander is proposed to alleviate light emitting diode(LED) non-linearity as well as peak-to average power ratio (PAPR) reduction in a VLC system.A $mu$ law compander is used to compress the peak valued signal and enhances small amplitudes to lower the PAPR. The work attains optimal PAPR and improves bit error rate (BER) of the system at low signal to noise values. The non-linear characteristic of a LED used as the transmitter in a VLC system leads to damaging effect whiole using OFDM in an optical system. The combination scheme improves LED non-linearity for low input backoff power(IBO). In the work,non-linearity is characterised using error vector magnitude (EVM) in percentage. The proposed method shows a 5 $%$ EVM improvement for 0dB IBO.The paper provides a choice for a trade-off among PAPR reduction,BER and reduced non-linearity.
section*{Keywords}OFDM,VLC,PAPR,Precodeing,Companding,BER
section{Introduction}
The high-speed wireless services such as high definition(HD)video and picture transmission, internet protocol (IP) based voice calls,online games and videos,e-commerce transactions,etc urge for the fast speed mobile data network.
section{Optical Modulation Schemes}
In this section,conventional ACO-OFDM,PAM-DMT and DCO-OFDM schemes as well as hybrid modulation schemes such as HACO-OFDM,ADO-OFDM and LACO-OFDM are described.
subsection{Conventional Schemes}
subsubsection{ACO-OFDM}In ACO-OFDM,only the odd sub-carriers carry data while the even sub carriers are set to zeros in the frequency domain.The input signal to the textit{N}-point IFFT,textbf{X},consists of only odd components and satisfies the Hermitian symmetry as textbf{X}=[0,Xtextsubscript{1},0,Xtextsubscript{3}…..,Xtextsubscript{N/2-1},0,Xtextsuperscript{*}textsubscript{N/2-1}….,Xtextsubscript{3},Xtextsubscript{1}].The time-domain signal xtextsubscript{n} has the antisymmetric property as xtextsubscript{n}= -xtextsubscript{n+N/2},(0$leq$ ntextless N/2).The ACO-OFDM signal, xtextsubscript{ACO,n},is ensured non-negative by clipping the negative part without losing any information as
begin{equation}

x_{Aco,n}=
begin{cases} x_{n}, &text{ $x_{n} geq 0$,}\
0, &text{ $ x_{n} < 0$.}\
end{cases}

end{equation}
In [11], it has been proved that the clipping noise only falls on the even sub-carriers,which will not affect the demodulation of the transmitted data.
subsubsection{PAM-DMT:}In PAM-DMT, signals drawn from PAM are used to modulate the imaginary part of each sub-carrier except the 0-th and N/2-th sub-carriers. The input to the IFFT block can be represented as
$textbf{Y}=0,Y_{1},Y_{2},ldots,Y_{N/2-1},0,Y^*_{n/2-1},ldots,Y^*_{1}$,
where $Y_{k}=ib_{k},b_{k}(k=1,2,ldots,N/2-1)$ is the real valued PAM signal and $i^2=-1$. As shown in [15], the time domain signal $y_{n}$ follows the symmetry as $y_{n}=-Y_{N-n},(0leqslant n < N/2)$.Therefore, PAM-DMT signal $y_{PAM,n}$ can be clipped at zero without any loss of information as
begin{equation}

y_{PAM,n}=
begin{cases} y_{n}, &text{ $y_{n} geq 0$,}\
0, &text{ $ y_{n} < 0$.}\
end{cases}

end{equation}
subsubsection{DCO-OFDM:}In DCO-OFDM,the signal $Z_{n}$ is generated by the IFFT is guaranteed is guaranteed to be positive by adding a DC bias, $B_{Dc}$. After the superposition, the remaining negative signal will be clipped at zero, leading to a clipping noise,ctextsubscript{n} which depends on DC bias. Then the transmitted DC-OFDM signal $Z_{DCO,n}$ is given by
begin{equation}
Z_{DCO,n}=
z_{n}+B_{DC}+C_{n}.
end{equation}
Moreover, $B_{DC}$ is usually relative to the electrical power of the signal $z_{n}$, and $B_{DC}=musqrt{E{Z_{n}^2}}$,where $mu$ is a proportional constant and $B_{DC}$ is defined as 10logtextsubscript{10}$(mu^2+1)$ dB.
subsection{Hybrid Schemes}
Figs.1 and 2 illustrate the transmitters and receivers of HACO-OFDM, ADO-OFDM and LACO-OFDM, respectively.

%begin{figure}centering
%the par is necessary after each text to make the baselineskip take effect
begin{tikzpicture}[node distance=1.5cm, auto]

node (start) [block] {N-point FFT};
node[block,right of= N-point FFT](process1){Process1}

end{tikzpicture}

%caption{Block diagram of Alfvenic aurora detection algorithm.}
label{fig:blockcv}
%end{figure}
end {document}

Solution 1

The following solution uses the plot command to draw the curved lines. The chessboard like fields are created by drawing each second stripe in horizontal and vertical direction and the even odd rule for filling.

documentclass{article}
usepackage{tikz}

begin{document}
  begin{tikzpicture}[
    x=10mm,
    y=10mm,
    z={(2.5mm, 0)},
  ]
    newcommand*{CylinderLength}{5}
    newcommand*{CylinderRadius}{1}
    newcommand*{HorizontalStripes}{5}
    newcommand*{VerticalStripes}{10}
    pgfmathsetmacro{HorizontalStripeAngle}{180/HorizontalStripes}
    draw
      (CylinderLength, CylinderRadius) 
      -- plot[domain=90:270, smooth, variable=t]
         (0, {CylinderRadius*sin(t)}, {CylinderRadius*cos(t)})
      -- ++(CylinderLength, 0) 
      plot[domain=0:360, smooth cycle, variable=t]
      (CylinderLength, {CylinderRadius*sin(t)}, {CylinderRadius*cos(t)})
    ;
    fill[black, even odd rule]
      % Vertical stripes
      foreach x in {2, 4, ..., VerticalStripes} { 
        plot[domain=90:270, smooth, variable=t] 
        ({(x-1)*CylinderLength/VerticalStripes},
          {CylinderRadius*sin(t)}, {CylinderRadius*cos(t)})  
        -- ++(CylinderLength/VerticalStripes, 0)
        -- plot[domain=90:270, smooth, variable=t]  
           (x*CylinderLength/VerticalStripes,
             {CylinderRadius*sin(-t)}, {CylinderRadius*cos(-t)})
        -- cycle
      }
      % Horizontal stripes
      foreach y in {2, 4, ..., HorizontalStripes} {
        plot[domain=90+(y-1)*HorizontalStripeAngle:
                    90+y*HorizontalStripeAngle,
             smooth, variable=t]
        (0, {CylinderRadius*sin(t)}, {CylinderRadius*cos(t)})
        -- ++(CylinderLength, 0)
        -- plot[domain=-90-y*HorizontalStripeAngle:
                       -90-(y-1)*HorizontalStripeAngle,
                smooth, variable=t]
           (CylinderLength, {CylinderRadius*sin(-t)},
             {CylinderRadius*cos(-t)})
        -- cycle
      }
    ;  
  end{tikzpicture}
end{document}

Remark to the comments, that a semicolon is missing. I cannot reproduce this error message with the versions posted below. The fill command contains two foreach loops, for the horizontal and vertical stripes, otherwise the trick with the even odd rule would not work. Thus the semicolon for the fill command is on line 49 right before the closing end{tikzpicture}.

 *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)
    tikz.sty    2013/12/13 v3.0.0 (rcs-revision 1.142)
     pgf.sty    2013/12/18 v3.0.0 (rcs-revision 1.14) 
  pgfrcs.sty    2013/12/20 v3.0.0 (rcs-revision 1.28) 
everyshi.sty    2001/05/15 v3.00 EveryShipout Package (MS)
  pgfrcs.code.tex
 pgfcore.sty    2010/04/11 v3.0.0 (rcs-revision 1.7)
graphicx.sty    2014/04/25 v1.0g Enhanced LaTeX Graphics (DPC,SPQR)
  keyval.sty    2014/05/08 v1.15 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/error messages (HO)
 ltxcmds.sty    2011/11/09 v1.22 LaTeX kernel commands for general use (HO)
  pgfsys.sty    2013/11/30 v3.0.0 (rcs-revision 1.47)
  pgfsys.code.tex
pgfsyssoftpath.code.tex    2013/09/09  (rcs-revision 1.9)
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 v3.0.0 (rcs-revision 1.7)
pgfcomp-version-1-18.sty    2007/07/23 v3.0.0 (rcs-revision 1.1)
  pgffor.sty    2013/12/13 v3.0.0 (rcs-revision 1.25)
 pgfkeys.sty    
 pgfkeys.code.tex
 pgfmath.sty     
 pgfmath.code.tex
  pgffor.code.tex
    tikz.code.tex
supp-pdf.mkii
pdftexcmds.sty    2011/11/29 v0.20 Utility functions 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 Manage graphics extensions (HO)
kvdefinekeys.sty    2011/04/07 v1.3 Define keys (HO)
kvoptions.sty    2011/06/30 v3.11 Key value format for package options (HO)
kvsetkeys.sty    2012/04/25 v1.16 Key value parser (HO)
etexcmds.sty    2011/02/16 v1.5 Avoid name clashes with e-TeX commands (HO)
epstopdf-sys.cfg    2010/07/13 v1.3 Configuration of (r)epstopdf for TeX Live
 ***********

Solution 2

Run with xelatex or latex->dvips->ps2pdf

documentclass[pstricks,border=5pt]{standalone}
usepackage{pst-solides3d}

begin{document}
psset{Decran=15,viewpoint=20 -60 0 rtp2xyz}
begin{pspicture}(-1,-2)(5,2)
pstVerb{ /ELEMENT 0 store }
psSolid[object=cylindrecreux,h=5,r=1.5,RotY=90,ngrid=11 15,
  fcol= 0 2 165 { (black) } for ]% for loop with step 2
end{pspicture}
end{document}

And the same for a 8×8 chessboard :

documentclass[pstricks,border=5pt]{standalone}
usepackage{pst-solides3d}

begin{document}
psset{Decran=15,viewpoint=20 -60 0 rtp2xyz}
begin{pspicture}(-1,-2)(7,2)
pstVerb{ /Element 0 store }
psSolid[object=cylindrecreux,h=8,r=1.5,RotY=90,ngrid=8 8,
  fcol= 32 {
    Element (black) /Element Element 2 add store    
    Element 8 mod 0 eq 
      { /Element Element 1 add store } 
      { Element 8 mod 1 eq { /Element Element 1 sub store } if } ifelse } repeat
]
end{pspicture}
end{document}

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