Questions in topic: "optimizer"
https://developer.ibm.com/answers/questions/topics/single/240170.html
The latest questions for the topic "optimizer"Why does Cplex provide feasible solutions with constraints containing slack?
https://developer.ibm.com/answers/questions/499882/why-does-cplex-provide-feasible-solutions-with-con.html
I developed a linear mathematical programming model in Visual Studio (C++) and solved the problem using Cplex (12.7.1). However I noticed some strange behavior of Cplex. For some problem instances, Cplex provides a feasible (non-optimal solution), that could be easily improved. A simplified example of the mathematical model is as follows:
Minimize A
Subject to
cX – dY <= A
dY – cX <= A
X, Y binary, A continuous, c,d parameters
Given the values of X and Y in the provided feasible (non-optimal) solution, there is slack on both constraints. The continuous A variable could be easily reduced given the values of decision variables X and Y. I understand that Cplex provides a solution that is feasible given the constraints of the problem. However when branching and solving the simplex in a branch to create a feasible solution, why does this simplex calculation result in these two non-binding constraints? What can I do to ensure Cplex always provides at least a solution with binding constraints?cplexoptimizerWed, 03 Apr 2019 09:31:16 GMTTeunvanGilsWhy does Cplex provide slack on constraints when providing a feasible solution?
https://developer.ibm.com/answers/questions/499879/why-does-cplex-provide-slack-on-constraints-when-p.html
I developed a linear mathematical programming model in Visual Studio (C++) and solved the problem using Cplex (12.7.1). However I noticed some strange behavior of Cplex. For some problem instances, Cplex provides a feasible (non-optimal solution), that could be easily improved. A simplified example of the mathematical model is as follows:
Minimize A
Subject to
c*X – d*Y <= A
d*Y – c*X <= A
X, Y binary, A continuous, c,d parameters
Given the values of X and Y in the provided feasible (non-optimal) solution, there is slack on both constraints. The continuous A variable could be easily reduced given the values of decision variables X and Y. I understand that Cplex provides a solution that is feasible given the constraints of the problem, but the solution can be easily improved by removing the slack on the constraints and reducing the A variable. Why is Cplex not able to provide this solution without slack on the constraints? What can I do to ensure Cplex always provides at least a solution with binding constraints?cplexoptimizationoptimizerWed, 03 Apr 2019 08:55:06 GMTTeunvanGilsIs the Optimizer that is built into BPM 8.5 included in 8.6 and the new Business Automation Workflow?
https://developer.ibm.com/answers/questions/487484/is-the-optimizer-that-is-built-into-bpm-85-include.html
We are working on upgrading our BPM system, and we have had some inquiries about the optimizer tool. We haven't used it much in the past, but don't want to start using it if it's not going to be available in the new systems.
Thanks.workflowibm bpm 8.5optimizer8.6.Tue, 08 Jan 2019 19:12:10 GMTmbrees86Formulation in Cplex
https://developer.ibm.com/answers/questions/480392/formulation-in-cplex.html
Hi,
Is someone familiar with Cplex and could help me to formulate the attached equation in Cplex.[link text][1]
Xij, is the effective age of component i at the start of period j.
X´ij, is the effective age of component i at the end of period j.
Alpha is the improvement factor.
T: Length of the planning horizon.
J: Number of intervals.
[1]: /answers/storage/temp/25263-model.pdfcplexoptimizationoptimizerWed, 14 Nov 2018 07:51:56 GMTNadLIf statment with bounds in Cplex
https://developer.ibm.com/answers/questions/479976/if-statment-with-bounds-in-cplex.html
Hi, I want to model a production with two machines(m), 6 equiments (w) and 5 products (p), with macro-(t) and microperiods (s) in Cplex. Which i have done so far, now i want to modell the effective age of my equipment, which i calculate as below. I want to undertake maintenance when the equipment comes to a production of w1=500, w2=450...(Maint[w]) but as i modelled it, it does not work. And the cleaning has to be undertaken between 135 and 185 which does not work as well. Additionally the cleaning as an affect of 0.05 on the effective age and the maintenance of 1. I attached my model in the pdf file.
forall(s in S,p in P, t in T, w in W) if(t == 1 && s == 1){
ea[w][t][s]>=sum(p in P, m in M)r_x[m][w][p][t][s]*0.001;
}else if(t > 1 && s < 2){
ea[w][t][s]>=(ea[w][t-1][3]+sum(p in P, m in M)r_x[m][w][p][t][s]*0.001)-b_maint[w][t-1][3]-(b_clean [w][t-1][3]*0.05);
}else if (s > 1){
ea[w][t][s]>=(ea[w][t][s-1]+sum(p in P, m in M)r_x[m][w][p][t][s] *0.001)-b_maint[w][t][s-1]-(b_clean[w][t][s-1]*0.05); }
forall(w in W, t in T, s in S)
(Maint[w]<=sum(p in P, m in M)r_x[m][w][p][t][s])<=(b_maint[w][t][s]<=1);
forall(w in W, t in T, s in S)
(135<=sum(p in P, m in M)r_x[m][w][p][t][s] && sum(p in P, m in M)r_x[m][w][p][t][s] <=185)==(b_clean[w][t][s]==1);
[1]: /answers/storage/temp/25222-model-opl-12.pdfcplexfunctionoploptimizationoptimizerMon, 12 Nov 2018 12:23:28 GMTNadLCplex function
https://developer.ibm.com/answers/questions/479945/cplex-function.html
Hi,
I have the following objection function for a production line, with m=2, p=5, w=6, t=3 and s=3:
dexpr float obj_production_cost=sum (m in M, p in P,t in T, s in S, w in W) c_prod[m][w][p] * r_x[m][w][p][s][t];
forall(t in T, p in P)
if(t<2){
INV0[p] + Backorder0[p]+sum(m in M, s in S, w in W)(r_x[m][w][p][t][s]*b_x[p][w][m])-r_INV[p][t]-r_Backorder[p][t]==dem[p][t];
}else { r_INV[p][t-1] - r_Backorder[p][t]+sum(m in M, s in S, w in W)(r_x[m][w][p][t][s]*b_x[p][w][m])-r_INV[p][t]+r_Backorder[p][t-1] ==dem[p][t];}
I want now to set t=7 but Cplex then tells me that my r_x is out of bound?cplexfunctionoploptimizationoptimizerMon, 12 Nov 2018 08:51:10 GMTNadLUnable to download IBM CPLEX Free Edition
https://developer.ibm.com/answers/questions/478672/unable-to-download-ibm-cplex-free-edition.html
Trying to download the IBM CPLEX Free Edition, but running into this error:
*This product is subject to strict US export control laws. Prior to providing access, we must validate whether you are eligible to receive it under an available US export authorization.
Your request is being reviewed.
Upon completion of this review, you will be contacted if we are able to give access. We apologize for any inconvenience.
message code: 53e*
I am trying to download it in the US, and have checked that the location is set to United States - English. What's going wrong?cplexilogoptimizerSun, 04 Nov 2018 16:20:32 GMTNTrieuMinimize Max Value - CPLEX Matlab Toolbox
https://developer.ibm.com/answers/questions/476782/minimize-max-value-cplex-matlab-toolbox.html
Dear community,
how do I formulate a minmax problem with the CPLEX Matlab Toolbox?
I would like to formulate the following expression:
Min Dmax, with D being a vector (dimension 1x336).
... in the form of a cplexmilp problem as described [here][1].
Thanks and regards,
Mathias
[1]: https://www.ibm.com/support/knowledgecenter/en/SSSA5P_12.6.2/ilog.odms.cplex.help/refmatlabcplex/html/cplexmilp-m.htmlcplexoptimizationoptimizermatlabTue, 23 Oct 2018 07:49:49 GMTMathias_RWTHcplexlsqmilp - bad results, but why?!
https://developer.ibm.com/answers/questions/476319/cplexlsqmilp-bad-results-but-why.html
Dear community,
based on a previous question I applied a cplexlsqmilp solver (toolbox, Matlab API) to a problem as follows:
MIN (SUM [ (R+X)^2 ])
,with R being a given scalar vector.
This should to my understanding result in X always having the opposite sign of R to minimize the total sum. However, the solver gives back bad results. The code goes as follows (I will not post the constraints, as these are already proven to be correct in a cplexmilp probelm):
The optimization function:
C = eye(length(R)); % miqcp problem: min norm(C*x-d)^2
d = -R;
My constraints (already proven to be correct in a cplexmilp problem):
a1 = eye(length(R));
a2 = a1*-1;
tril1 = tril(ones(length(R)/2));
tril1 = tril1 * eta_c;
tril2 = tril(ones(length(R)/2));
tril2 = tril2 * eta_d;
a3 = [tril1, tril2];
a4 = a3*-1;
b1(1:2*length(R),1) = Pmax; % Power constraint
b2(1:length(R),1) = Smax/2; % Energy constraint
lb1(1:length(R)/2,1) = 0; % sign of x (charging cannot be negative)
lb2(1:length(R)/2,1) = -inf; % sign of x (discharging can be negative)
ub1(1:length(R)/2,1) = inf; % sign of x (charging can be positive)
ub2(1:length(R)/2,1) = 0; % sign of x (discharging cannot be positive)
Aineq = [a1; a2; a3; a4]; % Linear inequality constraint: Aineq*x <= bineq.
bineq = [b1; b2];
Aeq = []; % Linear Equality constraint: Aeq*x = beq
beq = [];
lb = [lb1; lb2]; % Lower and upper bounds
ub = [ub1; ub2];
A set of SOS constraints (I basically split the X vector in two halfs, the first one is either 0 or positive, the second one either 0 or negative. This has also been proven beforehand):
sostype = repmat('1', [1, length(R)/2]); % Replicate 1 time vertically, n times horizontally.
v1 = 1:length(R); % Create Vector
v2 = reshape(v1, [], 2)'; % Reshape Vector To 2-Row Matrix
sosind = mat2cell(v2, 2, ones(1,size(v2,2))); % Create Cell Array
v3(1:length(R)/2,1) = 0;
v4(1:length(R)/2,1) = 1;
v5 = [v3 v4]';
soswt = mat2cell(v5, 2, ones(1,size(v5,2)));
ctype = repmat('C', [1, length(R)]); % Replicate 1 time vertically, n times horizontally.
And my solver call:
options = cplexoptimset;
options.Display = 'on';
[x,resnorm] = cplexlsqmilp(C,d,Aineq,bineq,Aeq,beq,sostype,sosind,soswt,lb,ub,ctype,[],options);
Does anybody see the flaw in here?! For an exemplary set of R see below:
0,0713293650793651; 0,0508184523809524; 0,0384176587301587; 0,0359871031746032;
0,0406250000000000; 0,0593005952380952; 0,0930555555555556; 0,121701388888889; 0,028050595238095; -0,230606150793651; -0,372969246031746; -0,423435515873016; -0,389230158730159; -0,279453373015873; -0,0548750000000000; 0,0879742063492064; 0,104836309523810; 0,142881944444444; 0,167261904761905; 0,175570436507937; 0,155778769841270; 0,132316468253968; 0,127058531746032; 0,094692460317460; 0,071329365079365;cplexoptimizationoptimizermatlabFri, 19 Oct 2018 07:16:36 GMTMathias_RWTHFormulation of CPLEX Optimization Function
https://developer.ibm.com/answers/questions/475984/formulation-of-cplex-optimization-function.html
Dear community,
I am currently and repeatedly struggling with the formulation of an optimization function for Matlab's CPLEX API.
I am trying to formulate the following function in CPLEX syntax:
MIN ( SUM [ (P+X)^2 ])
, with P being a given scalar vector in the dimension of 1x8760 and X being the variable to be optimized (same dimension).
It seems to me that this must be simple. However, I just can't find an approach here. I must confess that I have very little experience in optimization, even less with CPLEX.
Thankful for every bit of help.
Best,
MathiascplexoptimizationoptimizermatlabWed, 17 Oct 2018 18:50:36 GMTMathias_RWTHUnable to download IBM ILOG CPLEX Optimization Studio Free Edition
https://developer.ibm.com/answers/questions/468778/unable-to-download-ibm-ilog-cplex-optimization-stu.html
Hello,
I have been trying to download the IBM ILOG CPLEX Optimization Studio Free Edition this whole afternoon, but I couldn't because I kept receiving this message:
This product is subject to strict US export control laws. Prior to providing access, we must validate.... Upon completion of this review, you will be contacted if we are able to give access. We apologize for any inconvenience. message code: 53e
I don't live in the US, and it's the first time that I encounter such a problem while trying to download a software.
I actually need to work with this software as soon as possible, Has anybody already encountered such a problem? Does anybody know how can I accelerate this process please? or if the reviewing process takes days to be complete?
PS: I have tried to contact the IBM support, they told me that this is a technical problem but they can't help because I am not using the paid version, also for some reason I couldn't open a case to state my problem.cplexilogoptimizerWed, 05 Sep 2018 14:17:50 GMTsarussSpeaking of the Process Optimizer... Will it be ported to support the new BPM V8.6.x process diagrams?
https://developer.ibm.com/answers/questions/429704/speaking-of-the-process-optimizer-will-it-be-porte.html
Right now the Process Designer Desktop is deprecated, that is also true for the Process Optimizer. None of them are able to work with the new process diagrams of BPM 8.6.x. I've been searching in the knowledgecenter and developerworks site but there is no word of a future path for that part of the process designer. Will the process optimizer be removed from BPM?bpmmigrationprocess designeroptimizerWed, 07 Feb 2018 17:14:14 GMTAleToledoExplain plan Query Cost Vs Time taken by the query
https://developer.ibm.com/answers/questions/349024/explain-plan-query-cost-vs-time-taken-by-the-query.html
One of my queries runs for 30 mins with Opt level 3 and it completes in 2 mins with Opt level 5.
However, Explain plan with Opt level 3 shows query cost as 557773 and
explain plan with Opt level 5 shows query cost as 1.03584e+06.
Would like to understand if there is any relation between "Explain plan Query Cost' and 'Time taken by the query'. Please help me to understand.optimizerexplainTue, 24 Jan 2017 21:32:47 GMTPMJ_NISWhy query with High query cost runs faster and with less cost runs longer ?
https://developer.ibm.com/answers/questions/349019/why-query-with-high-query-cost-runs-faster-and-wit.html
I have a query which runs for more than 30 mins with Opt level 3 set. Explain plan shows query cost of 557773.
Same query with Opt level set to 5 shows query cost in the explain plan as 1.03584e+06 but completes within 5 mins.
Would like to understand the reason for the same ?queryoptimizerexplainTue, 24 Jan 2017 21:09:31 GMTPMJ_NISHow can I influence Netezza query optimizer?
https://developer.ibm.com/answers/questions/307364/how-can-i-influence-netezza-query-optimizer.html
The Netezza query optimizer is a cost-based optimizer; that is, it determines the cost for the various execution alternatives and chooses the path with the least cost as the optimal execution path for a particular query. The execution plan with the lowest cost among all candidate plans is considered the most efficient. However, in certain situations the Netezza optimizer might not provide the best query plan that leads to the best query performance. How can I tweak the Netezza query optimizer so it produces batter query performance?nzpdanetezzanzsupportpdanpsqueryoptimizerThu, 29 Sep 2016 16:52:41 GMTSanjitChakrabortyCan we apply Transaction logs from DR
https://developer.ibm.com/answers/questions/301804/can-we-apply-transaction-logs-from-dr.html
We have full online backup of prod of pre DR shifting.
1. Can we restore the database with that backup image in our testing server and rollforward with the logs of DR database once we are shifted to DR as Log sequence of both the databases will be the same (Same database replicated using Storage Replication from PROD to DR) ?
2. Can we apply the transaction logs of post DR in the same rollforwarding sequence?db2optimizermqtThu, 08 Sep 2016 16:02:50 GMTPrashantKapseDb2 connect server licence
https://developer.ibm.com/answers/questions/301794/db2-connect-server-licence.html
We do see DB2 server connect and enterprise server installed on our server. Why DB2 connect server is also installed on all the server where DB2 enterprise server is installed. I have following two queries.
1. Is DB2 Connect server a component of DB2 Enterprise server and comes
along with DB2 Enterprise edition.
2. If no, do you see any Impact of removing this product.db2optimizermqtThu, 08 Sep 2016 15:46:02 GMTPrashantKapseBest practices for backup mechanisam
https://developer.ibm.com/answers/questions/301786/best-practices-for-backup-mechanisam.html
We would like to know backup mechanism and best practice to implement.db2optimizermqtThu, 08 Sep 2016 15:32:03 GMTPrashantKapseBest practices for DB2 Reorg
https://developer.ibm.com/answers/questions/301782/best-practices-for-db2-reorg.html
Can you please provide me best practices to do REORG on LOB Objects? Or how to get it done faster ?db2optimizermqtThu, 08 Sep 2016 15:28:19 GMTPrashantKapseHow to get IP address for user
https://developer.ibm.com/answers/questions/301777/how-to-get-ip-address-for-user.html
WE WANT IN OUR DB TO CAPTURE IP ADDRESS IN ORDER TO FIND OUT THE USER WHO HAS CREATED/MODIFIED ANY OBJECTS IN DB. PLEASE TELL THE PROCESS.db2optimizermqtThu, 08 Sep 2016 15:23:07 GMTPrashantKapseIXSCAN may be chosen in a partitioned database even when there are no predicates on the chosen index's columns
https://developer.ibm.com/answers/questions/301619/ixscan-may-be-chosen-in-a-partitioned-database-eve.html
IXSCAN may be chosen in a partitioned database even when there are no predicates on the chosen index's columnsdb2optimizerThu, 08 Sep 2016 03:22:59 GMTAjayMPatilWhat is 'Optimizer MQT' ? How it differs from other MQT?
https://developer.ibm.com/answers/questions/301616/what-is-optimizer-mqt-how-it-differs-from-other-mq.html
What is 'Optimizer MQT' ? How it differs from other MQT?db2optimizermqtThu, 08 Sep 2016 03:12:34 GMTAjayMPatilHow to fix SQL0437W rc=3 warning?
https://developer.ibm.com/answers/questions/300085/how-to-fix-sql0437w-rc3-warning.html
Sometimes SQL queries return the following warning, even when Runstats and Reorg is done on the underlying tables
SQL0437W Performance of this complex query might be sub-optimal. Reason code: "3".db2db2luwoptimizerThu, 01 Sep 2016 10:43:20 GMTJuileeMy dynamic SQL query performance has deteriorated, what can I check for?
https://developer.ibm.com/answers/questions/272481/my-dynamic-sql-query-performance-has-deteriorated.html
My dynamic SQL query performance has deteriorated, what can I check for?db2luwdbdsupportperformancesqloptimizerFri, 20 May 2016 00:12:33 GMTalvarobWhat Information should I look to collect/investigate for a SQL Performance/Optimizer Issue ?
https://developer.ibm.com/answers/questions/268736/what-information-should-i-look-to-collectinvestiga.html
What Information should I look to collect/investigate for a SQL Performance/Optimizer Issue ?db2luwdbdsupportsqloptimizerThu, 05 May 2016 07:16:28 GMTmercutio1970How can I use the historic analysis of Process Designer when the Process Server is not Online with the Process Center?
https://developer.ibm.com/answers/questions/240171/how-can-i-use-the-historic-analysis-of-process-des.html
One of my clients has a policy in which the Process Center environment (Development) won't be able to connect to the Process Server environment (Production).
Since they have this limitation. Will they be able to use the Process Optimizer module in the Process Designer with the PS in offline mode in the PC?
Is there a way to configure this functionality?bpmdevelopmentofflineproductionoptimizerMon, 23 Nov 2015 13:45:11 GMTAleToledo