Using own package problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg16150] Using own package problem*From*: Jan Krupa <krupa at alpha.sggw.waw.pl>*Date*: Sat, 27 Feb 1999 03:23:13 -0500*Organization*: http://news.icm.edu.pl/*Sender*: owner-wri-mathgroup at wolfram.com

I have defined the following a little bit extension of LinearProgramings function which works only with the inequalities (*) A.x>=b but I need to solve problems when some of the inequalities are replaced by equalities an myLinearProgramming function can solve such problems. Here is the definition I made: ---- myLinearProgramming[c_,A_,b_,d_]:= Module[{k,A1,A2,b1,b2,x0,Fx0},k=Length[d]; A1=Table[Part[A,d[[i]]],{i,1,k}]; A2=Join[-A,A1]; b1=Table[Part[b,d[[i]]],{i,1,k}]; b2=Join[-b,b1]; x0=LinearProgramming[c,A2,b2]; Fx0=c.x0;{Fx0,x0}] ---- Vector d tells which of the inequalities of A.x >=b are replaced by equalities. It seems to works very well, e.g.: In[1]:= c={1,-2,3,2}; A={{1,1,1,1},{3,1,-2,-1},{3,-2,4,-1},{2,3,-5,-1}}; b={1,10,3,-4}; d={1,4}; In[2]:= myLinearProgramming[c,A,b,d] Out[2]={41/16, {0, 1/16, 13/16, 1/8}} I would like to put the definition of myLinearProgramming in a Package form so following the chapter 2.6.10 Setting Up Mathematica Packages (pages 376-..) in The Mathematica Book I have tried the following file: BeginPackage["ExLinearProgramming`"] ExLinearProgramming::usage = "LinearProgramming[c,A,b] finds the vector x which minimizes the quantity c.x subject to the constraints A.x >= b and x >= 0. ExLinearProgramming[c,A,b,d] may be used when the inequalities in A.x >=b numbered by d[[1]],d[[2]],...,d[[Length[d]]] are replaced by equalities." Begin["`Private`"] ExLinearProgramming[c_,A_,b_,d_]:= Module[{k,A1,A2,b1,b2,x0,Fx0},k=Length[d]; A1=Table[Part[A,d[[i]]],{i,1,k}]; A2=Join[-A,A1]; b1=Table[Part[b,d[[i]]],{i,1,k}]; b2=Join[-b,b1]; x0=LinearProgramming[c,A2,b2]; Fx0=c.x0;{Fx0,x0}] End[] EndPackage[] I saved it: File/Save As Special/Package Format using the name ExLinearProgramming.m and put it in the directory /usr/local/mathematica/AddsOn/Applications Then in the Mathematica X Front end I type: In[1]:=<<ExLinearProgramming.m (shift enter) then In[2]:= ExLinearProgramming[c,A,b,d] Out[2]=ExLinearProgramming[{1,-2,3, 2},{{1,1,1,1},{3,1,-2,-1},{3,-2,4,-1},{2,3,-5,-1}},{1,10,3,-4},{1,4}] In[3]:=ExLinearProgramming[{1,-2,3, 2},{{1,1,1,1},{3,1,-2,-1},{3,-2,4,-1},{2,3,-5,-1}},{1,10,3,-4},{1,4}] Out[3]=ExLinearProgramming[{1,-2,3, 2},{{1,1,1,1},{3,1,-2,-1},{3,-2,4,-1},{2,3,-5,-1}},{1,10,3,-4},{1,4}] So the function ExLinearProgramming in the Package ExLinearProgramming.m does not work. I have tried also the following: In[4]:=$Packages Out[4]={"ExLinearProgramming`","Global`","System`"} In[5]:=?ExLinearProgramming Out[5]=Global`ExLinearProgramming The last command should give the description of usage of the package from the file ExLinearProgramming.m: "LinearProgramming[c,A,b] finds the vector x which minimizes the quantity c.x subject to the constraints A.x >= b and x >= 0. ExLinearProgramming[c,A,b,d] may be used when the inequalities in A.x >=b numbered by d[[1]],d[[2]],...,d[[Length[d]]] are replaced by equalities." but it gives only Out[5]=Global`ExLinearProgramming. How to get the description of usage appeared after command: In[]:=?ExLinearProgramming ? Int[6]:=$ContextPath Out[6]={"ExLinearProgramming`","Graphics`Animation`","Global`","System`"} In[7]:=Context[ExLinearProgramming] Out[7]=Global` In[8]:=?ExLinearProgramming`Private`* Out[8]=ExLinearProgramming`Private`A ExLinearProgramming`Private`A1 ExLinearProgramming`Private`A1$ ExLinearProgramming`Private`A2 ExLinearProgramming`Private`A2$ ExLinearProgramming`Private`b ExLinearProgramming`Private`b1 ExLinearProgramming`Private`b1$ ExLinearProgramming`Private`b2 ExLinearProgramming`Private`b2$ ExLinearProgramming`Private`c ExLinearProgramming`Private`d ExLinearProgramming`Private`Fx0 ExLinearProgramming`Private`Fx0$ ExLinearProgramming`Private`i ExLinearProgramming`Private`k ExLinearProgramming`Private`k$ ExLinearProgramming`Private`x0 ExLinearProgramming`Private`x0$ I have tried to use the example Collatz.m from the page 378 of The Mathematica Book but had similar problem with it. Could you please give some suggestion how to get the package worked? How to get the description and example of usage be available via the Help Browser and Help Index from the X Front End? Thank you in advance, Jan