Re: [Help-glpk] Beware of using Access and Excel tables with ODBC (SQL statement) in MathProg

[Noli Sicad]

Hi Andrew,

Yes, you are right. The coefficient in the distance between San Diego
- New York and San Diego Chichago were interchanged in Access and
Excel. I hand coded the Access data early morning (1AM) and export to
Excel the data the next day. While in sqlite I modified the SQL
statement from mysql for sqlite and run the sql statements.

I corrected the Access and Excel data. However, the Excel model still
persistent to have the wrong solution. I rebooted my computer. I do
again the ODBC setup for excel, to refresh the link. Still the excel
model got the wrong solution.

This is still solution to Excel

LOC1    LOC2    QUANTITY
San Diego       New York        325
San Diego       Topeka  275
Seattle Chicago 300

No entry for Seatle to New York.

Noli




On 2/12/10, Andrew Makhorin <address@hidden> wrote:
>> However, when converted
>> the 3 models into CPLEX format, the 3 models are exactly the same,
>> just ordering of the variables and constraints
>>  (see converted models below).
>
> Not the same.
>
>> \* Problem: transp_odbc_sqlite3 *\
>
>> Minimize
>>  cost: + 0.225 x(Seattle,'New_York') + 0.153 x(Seattle,Chicago)
>>  + 0.162 x(Seattle,Topeka) + 0.225 x('San_Diego','New_York')
>>  + 0.162 x('San_Diego',Chicago) + 0.126 x('San_Diego',Topeka)
>
>> \* Problem: transp_odbc_xls *\
>> Minimize
>>  cost: + 0.225 x('San_Diego',Chicago) + 0.162 x('San_Diego','New_York')
>>  + 0.126 x('San_Diego',Topeka) + 0.153 x(Seattle,Chicago)
>>  + 0.225 x(Seattle,'New_York') + 0.162 x(Seattle,Topeka)
>
> transp_odbc_sqlite3:
> 0.225 x('San_Diego','New_York')
>
> transp_odbc_xls:
> 0.162 x('San_Diego','New_York')
>
>