(* :Title: Histograf*)
(* :Author: Miroslava Dubcova, VSCHT *)

(* :Summary: Vykresleni histografu pro danou funkci f(x)
*)
(* :Context: Matematika`Histgr` *)
(* :Package Version: 1.0 *)
(* :Mathematica Version: 2.2 *)
(* :Copyright: Copyright Miroslava Dubcova *)
(* :History:
*)
(* :Keywords:
     Histgr
*)
(* :Warning:  *)

BeginPackage["Matematika`Histgr`"]
Histgr::usage=
      "Histgr[f,{x,a,b},x0,iter,options] Histograf realne funkce. f je realna fce,x je nazavisle promenna, a, b jsou koncove body intervalu, x0 je pocatecni hodnota, iter je pocet iteraci, options jsou parametry. Zde je parametr Points, Typ, PlotRange, implicitni hodnota je Points->100, Typ->1, PlotRange->All.";

Points::usage=
      "Points->n, parametr pouzity ve funkci Histgr, n znaci pocet delicich bodu intervalu <a,b>. Implicitni hodnota je Points->100";
Typ::usage=
      "Typ->n, parametr pouzity ve funkci Histgr, n znaci typ histpgramu, 1 - spojity, 2 - nspojity.";

Begin["`Private`"]
     Options[Histgr]={Points->100,Typ->1,PlotRange->All};
     Histgr[f_,{x_,a_,b_},x0_,iter_,options___]:=
       Module[{n,pole,i,xn,j,h,d,graf,typgr,range},
	      n=Points /. {options} /. Options[Histgr];
              typgr=Typ /. {options} /. Options[Histgr];
              range=PlotRange /. {options} /. Options[Histgr];
	      xn=x0;
              h=(b-a)/n;
              d=1/(b-a);
	      pole=Table[0,{n+1}];
	      For[i=0,i<=iter,i++,
		  {xn=f/.x->xn,
		   j=Floor[(xn-a)*d*n],
		   If[j>=0 && j<=n-1,
		     pole[[j+1]]++]}];
              pole[[n+1]]=pole[[n]]; 
        (*    graf=Table[{a+i*h,pole[[i+1]]},{i,0,n-1} ];*)
              If[typgr==1,
                cara=Table[Graphics[Line[{{a+i*h,pole[[i+1]]},{a+(i+1)*h,pole[[i+1]]},
                     {a+(i+1)*h,pole[[i+2]]}}]],{i,0,n-1}];
                Show[cara,Axes->True,PlotRange->range]];
              If[typgr==2,
                cara=Table[
                       Rectangle[{a+i*h,0},{a+(i+1)*h,pole[[i+1]]}],{i,0,n-1}];
                Show[Graphics[cara],Axes->True,PlotRange->range]];
	(*    ListPlot[graf,PlotJoined->True];  *)
              pole;]
       
End[]
EndPackage[]