Let’s Challenge SPIDER

Rafael,

You said: “I would dare to say on real life jobs Spider will be between 6% and 0% of optimal with an average of 3%, with a distribution close to 3%.” I wish we know how good our real life schedules are. I am afraid that your numbers are optimistic.

Consider this: there are more difficult benchmark problems to solve, like LA29 with 20 projects and 10 resources. I guess Spider’s schedule might be off by 20-30% in the LA29 case.

It seems to me that when the problem size is small, like FT06, a schedule of good software, like Spider, is very close to the optimum schedule. As the size and complexity of the problem grows, the schedules are further and further from the optimum, even for Spider. And the difference between Spider’s schedules and other software schedules grows and grows, as you said: “The bigger the schedule the more you will notice the difference between Spider and the rest.” I just like your analyses, so I read your posts very carefully.

Can you try LA29? Thanks.

Regards,

George

George,

You can download the viewer from the following link.

http://www.mediafire.com/?g7jc418oz91498c

I downloaded it from the Spider users access, it is allowed to distribute unlimited number of viewers. It is intended mainly for distribution by registered users of Spider. They provide the Demo at their website but not the Viewer, perhaps to avoid too much traffic or maybe because Demo and Viewer should not be installed on the same computer.

You will be able to check my file and let me know if there is any error, even when I compared my results with Vladimir model there is always a possibility of error, a good excuse for you to explore the software.

I have never used the viewer as I jumped from Demo to full version within two weeks. 

I will try LA-29 but on Monday, tomorrow Sunday is for family time, will go to the movies and latter will watch the Dallas Mavericks NBA Finals game on TV. Will keep in touch.

instance la29
 +++++++++++++++++++++++++++++
Lawrence 20x10 instance (Table 8, instance 4); also called (setc4) or (C4)
20 10
8 14 2 38 7 44 0 76 5 97 3 12 4 75 6 66 9 12 1 29
0 43 2 85 3 82 5 38 4 58 9 89 8 92 6 87 7 69 1 80
3 41 7  7 9  5 0 43 2 14 4  8 5 61 1 84 8 66 6 48
2 42 3 74 4 59 6 41 1  8 9 73 8 43 0 96 5 19 7 97
7 23 8 42 4 37 6 55 0  7 5  5 2 70 9 38 3 75 1 48
8  9 6 43 7 31 4 25 5 73 3 95 0 79 2 72 9 60 1 56
1  7 5 21 8 53 6 16 4 94 0 97 3 78 2 64 7 86 9 31
2 65 6 59 7 85 1 33 4 30 8 44 0 61 3 86 9 63 5 32
6 45 2 44 5 61 8 93 1 30 7 90 9 84 4 11 3 16 0 60
4 47 7 36 8 31 1 49 3 20 2 28 6 52 9 35 5 11 0 32
2 77 4 10 9 68 5 17 0 85 1 84 8 20 6 49 7 74 3 34
0 17 5  7 1 85 3 29 2 17 4 76 6 59 8 71 9 13 7 48
6 87 4 39 8 43 7 11 2 15 3 32 5 64 0 19 1 39 9 16
5 33 3 99 6 32 4 91 8 82 2 92 9 99 7 57 1 83 0  8
3 91 5 39 2 69 8 27 7  7 6 21 1 38 9 62 4 88 0 48
2 67 7 80 3 24 0 88 4 18 1 44 8 45 9 64 5 80 6 38
9 59 3 72 6 47 4 40 7 21 5 43 0 51 8 52 1 24 2 15
3 70 2 31 6 20 8 76 1 40 7 43 0 32 5 88 9  5 4 77
4 47 5 64 9 85 3 49 7 58 1 26 0 32 8 80 2 14 6 94
5 59 2 96 0  5 7 79 8 34 4 75 3 26 6  9 9 23 1 11
+++++++++++++++++++++++++++++
Best regards,

Rafael

Rafael,

I downloaded the Viewer, and I cannot find FT10 or FT06 projects. There are 10 demo projects there. I never used this software. Can you help me?

You got it. it is LA29. Just 200 activities. Is it a small project? I guess so, if large projects have hundreds of thousands activities.

The minimum makespan for LA29 is 1157.

Are Dallas Mavericks as good as…..   let’s say…..    Spider?

Regards,

George

From a previous posting.

Spider Demo is limited to 40 activities but if you want to explore the 10x10 schedule maybe using the Free Spider viewer you can explore the files. You can download the file from the following link.

http://www.mediafire.com/?65yqw27jtx48ys4

Just download and open to explore the file.

About NBA basketball my team is the Boston Celtics, they did not make it into the finals so I am following Dallas Maverick because a local plays with them, JJ Barea, is not a regular player but still a good bench player.

http://www.youtube.com/watch?v=lV9z8czMTLg

Good things in life are not expensive, going to the movies is not, a hamburger on the BBQ is not, watching a game on TV is not, even watching bikinis on the beach is not, here it is a 12 month a year pastime.

Regards,

Rafael

Rafael,

For minimum makespans of the benchmarks, see, for example,

http://www2.research.att.com/~mgcr/doc/hgajss.pdf, Table 3, column BKS (3^rd) or

http://faculty.bus.olemiss.edu/crego/papers/FF-JSSP.pdf, Table 1, column BKS (best known solution) and Table 2, column Opt.

I like your humor: “PS 54% off by P6 out of the box is not bad, I had worst expectations.” And people pay for it? Can you imagine their project savings if Spider was used? Is P6 an average software or there are some much worse? I think that is why we need comparisons, Olympic Games. We could have a simple-and-small-size set of PM problems, more-complex-and-average-size set of PM problems, and very-complex-and-big-size set of PM problems. And some medals for all competitors. No, I am not Spider’s salesman.

I got your FT10 file, thanks. And where is your youtube video of bikinis on the beach? I cannot find it in your post.

Regards,

George

Vladimir,

About your “I am curious about the results produced for the same schedules by production scheduling programs.” As far as I know, the quality of production schedules is similar like in project scheduling because of similar algorithms (heuristic rules) dominate the field.

About your “Comparing Spider schedules with optimal we can find the ways for further improvements.” Spider’s optimization algorithm “is rather complex iterative heuristics”, you said. Iterative heuristics, such as tabu search, genetic algorithm, ant colony optimization, or bee colony optimization, have several parameters to tune the algorithm. The number of iteration can be one such parameter. The higher the number of iteration the shorter the schedule; however, at the expense of calculation time.

In Spider, this parameter might be set too low in order to produce schedules fast at the expense of the quality of the schedules. This might be even necessary for very large schedules. For smaller schedules, however, we (user or Spider) could set the parameter higher to get much better schedules yielding big project savings. Dynamic tuning the parameters of Spider’s optimization algorithm: What do you think about this simple Spider’s improvement? If it is possible to dynamically tune Spider then I have some more ideas for improvements.

Sorry guys,

I must correct the optimum makespan for LA29. The optimum makespan is not known yet. Only the best known solution found so far is available, and it is 1130, if it is not an error. I have some papers reporting 1130 (like http://docsdrive.com/pdfs/ansinet/itj/2007/222-226.pdf, Table 1 and Table 2, column Optimum, or www.soc.napier.ac.uk/~benp/dream/dreampaper13.pdf , Table 1, column Optimum), some 1132, 1134, and some 1137. As far as FT06 and FT10, the optimum makespans are 55 and 930, respectively. Amen.

Regards,

George

George,

we use an approach that is similar to your proposal:

Standard option is traditional when the user selects resource allocation priorities,

Advanced is the first level, Optimization is the second level, Optimization Plus is the third level of optimization that do more and more iterations. When the standard or advanced option produce satisfactory schedules people can use them because the scheduling is faster.

We also added Previous Version Support to save time for further calculations and to make the schedules stable. When this option is selected the order of activity execution is kept like in selected previous version of the same project. Optimizing once you can use this option until the initial data changes become large saving time in project schedule calculation.

I entered initial information in days instead of minutes to be able to compare the schedules with the other PM softwares that do not schedule in minutes. The 5 days/week calendar is used.

Spider default schedule for 20 projects problem lasts 1337 work days, 15.5% longer than optimal:

Applying priorities the schedule can be improved. Next slide shows Project Resource Structure where activities belong to the same phase if they shall be done by the same resource. Applying phase priorities we can get better schedule like the next one with 1313 days duration:

P6 default schedule lasts 1707 days, 47.5% longer:

The best schedule of P6 achieved with Late Start priority lasts 1469 days that is 23% longer than optimal:

Spider file can be downloaded from http://www.mediafire.com/?77aq2txhyk35ci3

We could add further optimization if our users will demand it. But usually initial information in project management is much more uncertain than in manufacturing. The schedule shall be close to optimal and will be adjusted many times when additional information will become available. I expected that the demand for good scheduling engine in manufacturing is much more urgent. Genetic and similar algorithms are too slow for using in large project models but could be used in production scheduling where the number of activities is measured in hundreds, not thousands like in projects.

Best Regards,

Vladimir

Vladimir,

I like the idea of “Previous Version Support” to save time. I must remember it and use it in my software one day. I am a software developer of production scheduling systems with a similar optimization algorithm like Spider. My production scheduling system uses discrete event simulation for modeling and an iterative heuristic for optimization. I use a different name for iterative heuristics - metaheuristics.

How long did Spider calculate LA29?

You said: “I expected that the demand for good scheduling engine in manufacturing is much more urgent.” Well, I thought the opposite is true. As I know, manufacturing people want, in average, any fast schedule with no worry about the quality of the schedules.

As for your: “Genetic and similar algorithms are too slow for using in large project models but could be used in production scheduling where the number of activities is measured in hundreds, not thousands like in projects.” I thought that Spider is in the group of genetic and similar algorithms – iterative heuristics, metaheuristics. Why should other iterative heuristics be too slow for using in large project models? They can decrease the number of iterations too, like Spider. Even my iterative heuristic can do it and can be very fast with good schedules. Am I missing something?

I would say that an average production facility does not have thousands of activities; however, an average semiconductor wafer fabrication facility has hundreds of machines, thousands of orders/batches and thousands of activities all the time. But such facility is an extreme, very large and very complex. I worked for Japanese Sharp corporation developing scheduling software for their wafer fabrication facility in Japan. I used a parallel computer for faster scheduling.

Vladimir, there are more difficult benchmark problems than LA29. Other researchers are claiming that the most difficult benchmarks are ABZ7, ABZ8, and ABZ9. From my own testing, I must agree. In fact, I hate them because I tried very hard, and still I cannot get better results. You just want to improve your ugly schedules a bit, just a bit, but no mercy. Very, very frustrating.  Try those suckers, but I warn you do not get discouraged by the schedules.

Next time, let’s try some very easy problems like LA8-LA15.

Regards,

George

George,

Might be of your interest;

CANDIDATE RULES FOR MINIMIZING THE PROJECT DURATION

http://dde.teilar.gr/attachments/581/trautmann%5B2010a%5D.pdf

Unfortunately Spider is not included and the resource leveling capabilities under these sample jobs cannot test how these algoritms perform under other real life modeling needs like variable partial assignments or other type of links. I understand only FS no lag relationship is used on these samples jobs, not even different calendars with different non-work days are considered. 

Real life is quite complicated.

As you can see in this report, bad performance by P6 is not as bad among the even worst performance of the others. I agree with the conclusion, among the tested software, none is good.

Vladimir,

Just in case you did not noticed, George said, "I must correct the optimum makespan for LA29. The optimum makespan is not known yet. Only the best known solution found so far is available, and it is 1130, if it is not an error."

I understand for different schedules the "best" algorithm might differ, precisely this is what I like about Spider, it provides several options that allow for prioritization and others that look for optimal. Because my jobs are usually on the range of 500 to 700 activities and US$20,000,000.00 not big jobs but very frequent in our construction market, I would say computing time in these jobs should not be much of an issue, not even on a laptop.

If there are other algorithms that should be added because they are better under certain circumstances, why not adding these options. I have no problem with having many algorithm options, prioritization is what confuses me.

I would welcome a table, to select several algorithms and prioritization options of their own, and the computer, while I am having a coffee, will run them all and output on the table the durations obtained under each option. Maybe even some suggested prioritization order can be displayed in parenthesis as an assistance for us to select these. If I can checkmark on the table the algorithms to be run then I can un-mark some and continue with only a few until I decide not to go further, but I will have a summary of my options and their results. Of course the idea about the table can be further developed, a table similar to other tables in Spider, where even directly parameters can be changed directly, where line would be loaded or recalled from the resource leveling dialog box, even un-statusing and sequential runs can be scheduled, and so on ..., just a practical table, nothing really new.

Best regards,
Rafael

George,

LA29 scheduling took a second or two.

The schedules we tried are not typical for projects and it makes Spider optimization less effective. In projects we always have converging paths and Spider iterative scheduling looks for these points (intermediate results) trying to achieve these results faster. In production scheduling benchmarks paths are independent. There are features that are necessary for production scheduling (like planning set-ups) and not for project planning, there are project management requirements that are not critical in production scheduling (many different calendars, part time assignments, complex dependencies, data uncertainties, etc.). But Previous Version Support is useful for both. It not only minimizes recalculation time. When new schedule is quite different than the one that was earlier approved the problems of resource reassignments, creating different supply schedule, etc. make the changes too expensive to be implemented.

If you will look at PP discussions you will find that few planners are trying to optimize project schedules, most do not load resources in their schedules at all. So project planning culture is even worse than in manufacturing. Spider is very popular in Russia and some other East Europe countries but when I speak about schedule optimization abroad very few people understand what I am talking about.

I will try most difficult benchmarks on return from my current business trip. We are involved in many projects and I am travelling a lot. Easy problems are not attractive.

Best Regards,

Vladimir

Rafael,

Thanks for “CANDIDATE RULES FOR MINIMIZING THE PROJECT DURATION” paper. I will read it soon. I just spent 10 minutes reading the beginning of it. I read many papers. If you have an interesting one, send it to me (george.mejtsky@yahoo.com). I am interested in production/project scheduling, resource allocation, simulation,  optimization, and bikinis.

I have a question about your “I would say computing time in these jobs should not be much of an issue, not even on a laptop.”  In what timeframe would you expect to get your solution/schedule? How long are you/others willing to wait? 2-3 hours? More? The longer you wait the better the schedule can be found.

As for your “If there are other algorithms that should be added because they are better under certain circumstances, why not adding these options.”  How do you want to find a better algorithm? By testing, right? We are now doing some testing of Spider. What tests would you recommend?

I think Spider is better than most project scheduling software in many, if not all, circumstances. Do you know a situation where Spider would be worse? If an optimization software is better than others in one situation, it is probably as well better in most other situations.  Spider is even better than most production scheduling software, I believe. It is the iterative heuristic of Spider that is significantly better than priority/heuristic rules of the others.

I would bet that the schedule found by a priority/heuristic rule is very close, if not worse, to a randomly picked schedule. That’s why, I proposed to include in Spider the random/average priority. Not for use by the users of Spider, only for internal Spider’s referential use to calculate an “average” schedule in order to see how far from the “average” schedule the normal/optimized schedule is. I would like to compare the “average” schedule with the schedules of competitors.

Regards,

George

George,

Because of the rain, bikinis are temporarily out of service. Last year average rain was 40% over yearly average, 12 months of rain my friend, this year seems like another 12 months of even more rain, this is an Island so floodings are not big, water goes to sea very fast.  Tomorrow Barack Obama is coming to Puerto Rico, most probably he will get wet.

About resource leveling time I am willing to wait up to an hour if need be, so there is time to run a few schedule leveling on a day. We are talking about applications for the industry, on special occasions might be willing to wait more time. When we have a job in trouble many times the only way to compress the schedule is not by squeezing the resource leveling algorithm but by changing technology-logic and or preferential-logic, increasing resource availability, adding shifts and the like. Still no doubt efficient resource leveling algorithms are handy, ideally the optimal as they can make a substantial difference. As Vladimir said they can improve the quality of our schedules, with the use of these we can reduce idle time of planned resources.

Spider creates resource dependencies, perhaps this can be used to temporarily lock the schedule so schedule runs for logic without resource leveling can be performed fast, then after all logic modifications the resource dependencies can be released as to run true resource leveling without artificial links that might interfere. This functionality, perhaps unique of Spider, you might be interested to look at.

Agree resource leveling shall be developed by testing, I cannot see other way, in order for the testing not taking much time I believe relatively few activities schedules that create enough confusion to the algorithms shall be enough. Algorithms for our project type schedules as well as algorithms for production type schedules shall be developed and available on a single scheduling software as there is no such thing as the Universal Algorithm that works best for all schedules, to make it harder sometimes schedules combine both types of process. For the moment no such thing exists and even finding best prioritization strategy differs among the different software and even among different schedules within same software.

I am just a regular user that can use the tool as developed by the mathematical minds, I believe resource leveling algorithms can be improved, though not a simple task. I recognize sometimes by random I got some improvements, this is why I am asking for some way to record my settings and results as to make it easier to make some search by some kind of educated trial and error.

I believe Spider schedules and any software shall be compared to the other software, not against itself.

Sorry for not going any further but optimization methods is not my specialty, give me the tools and I will use them, by testing the tool and comparing to other software we will know how good it is.

Regards,

Rafael

Rafael,

Did Barack Obama get wet? And what about the Mavericks on Sunday? Barea is goooood!

Can you try to solve LA01 and LA16 by Spider? These are very easy to solve (easy to get the optimal schedules). Vladimir says: “Easy problems are not attractive.” So he will not solve easy problems. I think they could be important for us. If Spider finds the optimal schedules, or very close to the optimum (< 2% like FT06) then it is fine. However, if it is 3% or more then we have a small problem - to improve the schedule.

Vladimir,

I think Spider could be allowed to calculate schedules for FT10 or LA29 longer and find much better schedule. Why only 1, 2 seconds? As far as I know, the iterative heuristics, metaheuristics, work like this: they find the first schedule fast, in less than one second or so. They save the schedule, and continue in search for a better one. They search hundreds of schedules, until they find a better one, and save it, etc. In this way, they search and keep finding better and better schedules. They keep searching until a stopping criterion is reached. The stopping criterion can be the number of iterations, calculation time, or something else.

Vladimir, why not to allow users to select the calculation time as a stopping criterion? Rafael said: “About resource leveling time I am willing to wait up to an hour if need be, …” In this way on Resource Constrained Scheduling Options form, I could select 10 minutes or 30 minutes calculation time, and let Spider calculate for that time. I should get a much shorter schedule than with only 1, 2 seconds of calculation time. And we know the significant benefits for the company from this much shorter schedule.

In my job shop scheduling software, I do not have the calculation time criterion. I let the scheduling program run and run and search for a better and better schedule. I watch how fast the schedules keep improving. When I see that the rate of improving is slowing down too much, or I get tired waiting, I kill/stop the search for better schedules.

Regards,

George

There was no rain today, the next photo is just after his arrival. The Next photo just before his departure, he parked his vehicle in the wrong spot and lost the wheels.

But local mechanics fixed it and even revamped it to his specs as follows, he left very happy.

http://www.youtube.com/watch?v=Vf-ZiAC5mIs

LA01 duration out of the box 11.55 hours, got 11.30 hours if after optimization the advanced option is applied with super float as main prioritization rule.

For LA16 I got 17hours and 27minutes, out of the box.

Regards,

Rafael

Rafael,

I love the Obama’s revamped vehicle. But that gold inside is a bit too much, right?

How long did Spider calculate the schedules? Is it again “The calculation time is always at a blink of the eye, as soon as resource leveling icon is clicked” as you said?

The optimum makespan for LA01 is 666. So Spider’s 715 (11.55 hours, 11x60+55=715) is +7%, or 690 (11.30 hours, 11x60+30=690) is +4%.

The optimum makespan for LA16 is 945. So Spider’s 1047 (17 hours 27 minutes, 17x60+27=1047) is +11%.

For optimum (or the best found) makespans of the benchmarks, see for example

http://www.informs-sim.org/wsc08papers/088.pdf, Table 1 and 2, column OPT.

There is enough space for improvement in the schedules for these very small and easy problems. Perhaps, the calculation time of several more blinks of the eye will do it.

Rafael, did you notice that as the problem size (number of activities) grows, the difference between Spider’s schedule and the optimum grows even for easy problems?  

Let’s not forget that Spider’s competitors need much more improvements just to catch up with Spider.

Regards,

George

George,

Again calculations at the blink of the eye. Not all of our jobs are made up of thousands of activities. My jobs are usually around 600 activities.

Our scenarios usually are such that a single dominant chain makes up the critical path and the other parallel chains do have enough float as to even allow us to reduce the availability of resources as to reduce idle time, then as there is progress the job starts to lag we increase the availability of resources up to a practical limit, here the resource leveling algorithm becomes very relevant. In our jobs parallel process that share many resources usually have the same resource demand sequence such as it would be the case of 10 independent buildings on a housing complex, we usually offset them in a way resources move smoothly on a controlled way.

Our job are different but some improvement will always be welcomed.

You can download la16 from the following link.

http://www.mediafire.com/?ottbgt5q7gqxv99

Got la16 with a duration of 17.21 hrs (17:13) or 9% (17.21/15.75-1) over best known solution by applying individual activity priorities.

Best regards,

Rafael

George,

I did not find the optimal duration for abz7.

Spider schedule lasts 12 hours and 36 minutes:

The schedules created by Spider shall be stable. If somebody will calculate project schedule with the same initial data and the same options the results shall be the same also. Don't forget that the schedules may live several years and recalculated at least each week. That is why we cannot afford anything random. But our testing was very useful and we will strengthen Optimization Plus option. As I wrote earlier the samples are not usual for projects and Spider did not use its full potential for schedule optimization but they were still very useful and showed some ways for future improvements.

I transfered minutes to days and calculated the schedule both in Spider and P6.

Spider schedule: 756 days,

P6 Default schedule: 1071 days,

P6 Best schedule (Late start): 797 days,

Optimal schedule: ???

Best Regards,

Vladimir

Vladimir,

As I said before (6-15-2011): For optimum (or the best found) makespans/schedules of the benchmarks, see for example my conference paper

http://www.informs-sim.org/wsc08papers/088.pdf, Table 1 and 2, column OPT.

The optimum or the best found makespan/schedule for ABZ7 is 656 (time units).

Spider schedule: 756 days, +15% (756x100/656 - 100).

P6 Default schedule: 1071 days, +63%.

P6 Best schedule (Late start): 797 days, +21%.

Vladimir, did you read my post from 6-14-2011? In the part for you, I suggested to allow the users to select calculation time for Spider. Rafael is willing to wait for a Spider schedule up to an hour. What do you think of the suggestion? Is it practical or useful?

Can you try ABZ8 and ABZ9? They are as difficult as ABZ7.

Best Regards,

George

Thank you, George.

Yes, I have read your post and answered.

Spider Project shall produce certain schedules with the same sets of initial data and the same methods chosen. It is project management requirement. If the Contractor submits some schedule to the Client both shall be sure that if anybody will run the scheduling again the result will be the same. So we could not afford anything uncertain (like time of the scheduling and the number of iterations). There are other reasons like the need for project trend analysis.

So we can create additional steps for resource constrained scheduling (now there are Standard, Advanced, Optimization, Optimization Plus levels) but cannot afford any uncertainty in the way the schedule is calculated. We already slightly improved Optimization Plus in yesterday release.

And as I wrote earlier the sample projects in the set were specially created to be hard and they are especially hard for Spider because our approach to iterative improvement uses WBS, the points where paths are merged. Your examples remind the portfolio scheduling but for this task optimization does not mean the shortest duration.

For really large projects with complex resource assignments (skills, partial assignments, conditions on continious work, resource production and consumption, etc.) Spider scheduling may take hours. So algorithms that find the best result for the benchmark schedules taking minutes of calculation could not be used at all in the real life.

I will try other samples later or will ask somebody in our office to do it. For me it is not easy to find the time for entering data.

Best Regards,

Vladimir

Vladimir,

First, I must apologize for my misunderstanding of your answer. I do not have a deep knowledge of project scheduling, and mainly, I do not know how professional PM software like Spider works. By now I think I understand your answer. Anyway, thanks for your detailed response to my question.

For a change, I have one resource-constrained project scheduling benchmark problem for Spider. I took it from the PROJECT SCHEDULING PROBLEM LIBRARY (http://129.187.106.231/psplib/). It is the j301_1 instance with the optimal makespan 43. It is small (30 activities) and not too complex (single mode). You can download the j301_1 pdf file from http://www.4shared.com/document/zSX59zRv/j301_1_project_sched_benchmark.html

Vladimir, can you take a look at my software. I developed an optimization method called sweep algorithm. The method is based on discrete event simulation, and it can solve resource-constrained project scheduling problems. I tested the method by developing software, called Sweeper, and solving the job shop scheduling benchmarks with very good results. Sweeper can match the Spider’s results within 1-2 seconds, and as its calculation continues, it finds shorter and shorter schedules.

You can evaluate the method and software, and if you like it we can develop software, based on the method, which would solve your real-world project scheduling problems. Such software can be included in Spider. It would be a good complement to Spider’s other optimization software. As Rafael said (6-13-2011): “If there are other algorithms that should be added because they are better under certain circumstances, why not adding these options. I have no problem with having many algorithm options, prioritization is what confuses me.”

You can download a read_me text file from http://www.4shared.com/document/A5fBzFKS/read_me_Sweeper_exe.html

The read_me file has instructions for downloading, installing, and running Sweeper.exe. It also has links to my conference papers about the method and benchmark testing.

You can download a white paper about the method from http://www.4shared.com/document/mlba3MpK/Sweeper_explained.html

Rafael,

Can you take a look at Sweeper also? I am interested in your thoughts. Perhaps, you will even revamp Sweeper to your specs as local mechanics in San Juan fixed the Obama’s vehicle.

Best Regards,

George

George,

I tried those sample projects earlier. Spider Project j301_1 instance default duration is 43 days (optimal).

I will look at your method and we will discuss this matter further (not in this forum). There are certain requirements to any algorithms that we use for project, program, portfolio scheduling. These requirements include:

- Multiple dependencies between the same activities that link any point of preceding activity with any point of succeding activity with lags that can be positive and negative and measured in time of quantity units,

- Resources, activities, lags may have own unique calendars,

- If skills are assigned the scheduling engine shall select and assign the resources that have necessary skills basing on their availabilities and user defined criteria,

- Activity durations may be calculated basing on quantities of work to be done and assigned resource productivities, if skills were assigned the duration is not known before project scheduling,

- Resource assignments may be partial and variable (when resource workloads or quantities may change during activity execution),

- Not only renewable but also consumable resources shall be considered,

- Project financing shall be considered as one of many schedule constraints,

- Etc. (there are many other requirements that need to be followed).

Sample projects in both production and project sets are too simple in structure though hard for finding optimal solution. The scheduling algorithm shall take into consideration all possible constraints and conditions.

Production scheduling may have different requirements like taking into account set-up durations.

In any case a lot of work is ahead to make an algorithm practical.

Best Regards,

Vladimir

Defining project resources specify if they belong to special subcontractors or can be used by many of them. Spider Project will optimize project schedule taking this into account.

Another case: when subcontractors use the same resource but it does not make sense to move it from one subcontractor to another until certain work was done (due to the distance or other reasons). This is modeled using spatial resources. In particular case when two or more subcontractors work in the one place they can share common space and resource will be used by all of them in the optimized schedule.

Skill means that resources belonging ti Skill can do the same work though with different productivity. You may create skill that includes resources of different subcontractors. In this case Spider Project will select who will do the work basing on resource availability, user defined priorities and user defined criteria (minimal cost, largest productivity or something else).

Let me know if your question was answered.

Safwan,

it depends on how initial model was created.

If at the planning stage it was not assumed that Subcontractor 2 may replace Subcontractor 1 at point C, it will be necessary to replace resource assignments.

If such possibility was considered then it makes sense to assign Skills that include resources of both Subcontractor 1 and Subcontractor 2 and give resources of Subcontractor 1 higher priority. If Subcontractor 2 will be selected for doing this job it is sufficient to change resource priorities.

One more solution is creating conditional network. Spider Project has special activities that have zero duration and two states Yes or No. This activity precedes to two network branches. If condition of Switch is Yes one branch will be selected (and other ignored), if No then another. States of the Switch activity may be selected manually or basing on some user defined rule.

In your case it is reasonable to create Switch activity that precedes to start of point C execution and create two branches – one if the job will be done by Subcontractor 1 and second if point C will be done by Subcontractor 2. These branches may include different activities. Then you may set the rule like If the forecast of completing point B by Subcontractor 1 is later than certain date Switch will automatically select the state that means that point C will be done by Subcontractor 2.

It looks like using Switch activity is the best method in your case.

Dear all,

I finally found some time for what I wanted to do long ago - to put some videos on youtube about Spider Project. Nowdays people search most of the information is vedeo format. I myself struggle to understand things if I can't find information on yourtube

so, I created a channel, called Spider Project. Cool features 

At the moment it has only 2 videos, but I am planning to start slowly putting more vedeos there

Thank you Evgeny!

Here https://www.facebook.com/notes/%D0%BA%D0%B0%D0%BB%D0%B5%D0%BD%D0%B4%D0%B0%D1%80%D0%BD%D0%BE-%D1%81%D0%B5%D1%82%D0%B5%D0%B2%D0%BE%D0%B5-%D0%BF%D0%BB%D0%B0%D0%BD%D0%B8%D1%80%D0%BE%D0%B2%D0%B0%D0%BD%D0%B8%D0%B5/%D0%BA%D0%B0%D0%BA-%D1%81%D0%B0%D0%BC%D0%BE%D0%BC%D1%83-%D0%BD%D0%B0%D1%83%D1%87%D0%B8%D1%82%D1%8C%D1%81%D1%8F-%D1%80%D0%B0%D0%B1%D0%BE%D1%82%D0%B0%D1%82%D1%8C-%D0%B2-%D0%BF%D1%80%D0%BE%D0%B3%D1%80%D0%B0%D0%BC%D0%BC%D0%B5-spider-project/105030894237938/?hc_location=ufi you may find the references to Spider video lessons in Russian.

Marcus Possi may add videos that he created in other languages.

It makes sense to find all published videos and create a library.

There is also a channel for the Romanian branch.

https://www.youtube.com/channel/UC5ccl8-T9tlOJ_Cl9eXKqdw

Where Spider Project functionality is presented as a summary overview.

Vladimir - excelent idea. 

video - theme - language - duration

Videos ... Yes there is. (in Portuguese)

Every course we have here, due to our methodology, the online tutor creates a short video to make some comments about students exercises.

So, we have some playlists for our classes, and others for "corrections"

Here some of them.

(1) About Spider Project WEB-PI Spider Project WEB.PI

(2) Abou exercises SpU - revisão 2019

(3) About a private Spider Projectcourse  Spider Project CONAGP

(4) About a complete Spider Course 2017 - without risk analysis Spider SpP - 2017

(5) About a complete Spider Course 2010/2012 - without risk analysis Spider SpP - Curso Original - 2010/2013

(6) About a complete Spider Course 2017HD SpU - em alta resolução 2017

(7) About Spider Project Cost course Spider Project - Custos

(8) About Spider Project Cost Composition Course Spider Project -Composição de Custos

(9) About Spider Project Course CPM only Spider Project - CPM

(10) About Spider Project Support Assessoria Spider Project

(11) About 150h Spider Project Course Project Management Risk Analisys MC and 3 Scenarios  (just support) -here

Being elaborated for 2020.

(12) Mont Carlo for Project Management

(12) 3 Scenario for Project Management

by the way,

this year is completing 10 years of our "Spider Project - Top of Mind" effort.

Here in Brazil if you question a PM about PM tools, they will certain remind Spider Project, not only the popular application MSProject, to solve problems.  

Vladimir,

Spider has ton of features. I must say it is not that reasy to learn, to put it mildly

I think absence or proper video instructions in English really holds it from taking over the world.

My series of Spider Project. Cool features  is really intended to show only remarkable features, not to be a comprehensive step by step guide (I don't have that knowledge yet)