<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv=Content-Type content="text/html; charset=windows-1252">
<meta name=Generator content="Microsoft Word 12 (filtered medium)">
<style>
<!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
-->
</style>
<!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang=EN-GB link=blue vlink=purple>
<div class=WordSection1>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Hi Rohith,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'> Normally the generation time should be proportional to the
number of non-zeros – that also seems to apply quite well when going from your
case-1 to case-3. Would it be possible to try cases much bigger than case-5?
One reason for a sudden increase in generation time could be related to memory
consumption.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>There were recently some mails on this list related to
generation time – they might be relevant for you as well. It is possible that
you could speed up things by removing the ‘such_that’ and use sparse sets (I.e.
MP_subset )instead, but it is hard to tell without looking at the complete
model.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Regards, Tim <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'>
<p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:
"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> flopcpp-bounces@list.coin-or.org
[mailto:flopcpp-bounces@list.coin-or.org] <b>On Behalf Of </b>Rohith Kumar.H.C<br>
<b>Sent:</b> Monday, October 04, 2010 10:37 AM<br>
<b>To:</b> flopcpp@list.coin-or.org<br>
<b>Cc:</b> rohitkumar.hc@in.abb.com<br>
<b>Subject:</b> [FlopCpp] FLOP C++ Generation Time Issue<o:p></o:p></span></p>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Hello,<br>
We are incrementally building a complex model using FLOP C++.<br>
It has been noticed that, as new constraints and additional terms for objective
function are added the Flop C++ Generation time increases.<br>
The point to worry is that the increase is quiet sharp with change in problem
size.<br>
<br>
The analysis data has been presented below:<br>
<br>
Case-1 Case-2 Case-3
Case-4 Case-5<br>
Rows
6409
6409 12793
13177 13897<br>
Columns
6433
7657 14089
14233 14953<br>
Non-Zeroes
14729
18401 42081
43881 45465<br>
Generation Time (secs) 0.145
0.150 0.420
0.562 1.049<br>
<br>
We would like to know if this generation time can be reduced?<br>
If yes, then what measure need to be taken to bring this down?<br>
<br>
The constraints modeled use such_that to restrict the range of constraint. Does
this effect the overall performance?<br>
<br>
Also what could be the other possible reasons for increased generation times.<br>
<br>
Regards<br>
Rohith<o:p></o:p></p>
</div>
</body>
</html>