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Good day,
I have a DB, that have a 3000 strings and 40 integer columns, each of them describe something about 1 piece of product, for example, cost, resource, etc.
User type end sum for each column.
I need a feedback, what stack of 5 types of instruments fits max by each column to the user number.
For example, 7 hammers, 2 presses, 3 crowbar, 4 gloves, 5 glasses all together cost 154000 money, user input 150000, have a resource of 923000 hours, user input 920000 etc.
I don't know, how to google that question or use search for it, but if you can help me with it's name or, more of it, with building, i will release my end program under Open Source. Thank you very much for your time, sorry, if my English bad.
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Knapsack problem? Bin packing?
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It is looking like HomeWork !
I think some details are missing in the problem to fully understand what is the request?
It look like a simple counting problem.
What have you tried ? What is your problem ?
Patrice
“Everything should be made as simple as possible, but no simpler.” Albert Einstein
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Good day,
You can solve this problem by integer linear programming.![Rose | [Rose]](https://www.codeproject.com/script/Forums/Images/rose.gif)
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It is more like counting things.
like making a list of all names, and counting each you see a name
and printing the top 5 names.
Patrice
“Everything should be made as simple as possible, but no simpler.” Albert Einstein
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What have you tried so far in solving this?
"I've seen more information on a frickin' sticky note!" - Dave Kreskowiak
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Consider a warehouse with a number of shelves(Bins) that have number, length, width, height and limit Weight capacity.
The Items that place in this warehouse are a number of cubes that have number, length, width, height and weight.
The algorithm must find the right place for Items so Bins have the lowest waste of space. and sum of weight of Items in each bin must not be more than its weight capacity.
Items are placed at the edge of Bins. Namely, any Items can't be placed on Items, behind Items and in front of Items.
____________
I tried to write my problem as an integer linear programming model.
I can't Upload Image Of My Linear Model So I Insert This Link: Here Is the link
[Click Here]
______________
I tried this algorithm:
1_ Sort list of bins Smallest To Biggest.
2_ Sort list of items Biggest To Smallest.
3_ insert each item in first bin that have free space, by best fit algorithm.
It worked but can't swap bins when it's necessary. In other words it is not an optimized algorithm.
please help me 
modified 19-Aug-15 5:34am.
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Please don't repost the same message if it doesn't appear immediately.
All three of your posts went to moderation, and required a human to decide if they were or were not spam.
I have deleted the "spares".
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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The ILP model allows items to overlap inside a bin, is that supposed to be possible?
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Make copies of every item, one copy per "way it could fit in the bin", then ban combinations that overlap (for ex. in a 2x2x2 bin if you have an 1x1x2 item and a 1x2x2 item, then the case where the 1x2x2 is flat on the ground and the 1x1x2 item is standing upright is illegal). Also have a constraint that says that in total you will take the item exactly once (sum of all copies is 1).
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Hi,
Already seen this question somewhere
What about giving your actual code and explain where you have a problem ?
Patrice
“Everything should be made as simple as possible, but no simpler.” Albert Einstein
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Hi
This is about my "project course".
The project almost completed by c#.
[^]
______________
I used a greedy algorithm to placing items in bins so it is not a optimized algorithm. 
here is my placing function:
public static string placeItemInBin(Item itemToPlacing)
{
sortBinList();
LinkedListNode<Bin> binNode;
bool isPlaced = false;
int allSideStates = 1;
while (allSideStates <= 2)
{
binNode = listOfBins.First;
while (isPlaced == false && binNode != null)
{
if (binNode.Value.RemainLength >= itemToPlacing.Length)
if (binNode.Value.RemainWeight >= itemToPlacing.Weight
&& binNode.Value.Width >= itemToPlacing.Width
&& binNode.Value.Height >= itemToPlacing.Height)
{
LinkedListNode<Partition> partitionNode;
LinkedListNode<Partition> Best;
Best=null;
partitionNode = binNode.Value.parts.First;
while (partitionNode != null)
{
if (partitionNode.Value.num == -1
&& partitionNode.Value.size >= itemToPlacing.Length
&& (Best == null || partitionNode.Value.size <= Best.Value.size))
{
Best = partitionNode;
if (Best.Value.size == itemToPlacing.Length)
break;
}
partitionNode = partitionNode.Next;
}
if (Best != null)
{
string placingDetail;
if (Best.Value.size == itemToPlacing.Length)
{
Best.Value.num = itemToPlacing.Number;
itemToPlacing.CmPlaceInBin = Best.Value.cmBegin;
}
else
{
Partition newPart = new Partition(itemToPlacing.Length, itemToPlacing.Number,
Best.Value.cmBegin);
Best.Value.cmBegin += itemToPlacing.Length;
Best.Value.size -= itemToPlacing.Length;
binNode.Value.parts.AddBefore(Best, newPart);
itemToPlacing.CmPlaceInBin = newPart.cmBegin;
}
itemToPlacing.BinNumber = binNode.Value.Number;
binNode.Value.RemainLength -= itemToPlacing.Length;
binNode.Value.RemainWeight -= itemToPlacing.Weight;
binNode.Value.RemainVolume -= itemToPlacing.Length
* binNode.Value.Width * binNode.Value.Height;
isPlaced = true;
if (itemToPlacing.IsRotate == true)
placingDetail = "Item: Number: " + itemToPlacing.Number +
" (Rotated), Placed In Bin Number: " + binNode.Value.Number;
else
placingDetail = "Item: Number: " + itemToPlacing.Number +
" (Not Rotated), Placed In Bin Number: " + binNode.Value.Number;
return placingDetail;
}
}
binNode = binNode.Next;
}
itemToPlacing.changeSideState();
allSideStates++;
}
itemToPlacing.BinNumber = -1;
itemToPlacing.CmPlaceInBin = -1;
return "Not Found";
}
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You should update your question with the code, so everyone will see it.
Patrice
“Everything should be made as simple as possible, but no simpler.” Albert Einstein
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How do you define Best fit or Wasted space ?
your optimisation is combinational !
Which mean that to best fit a packet, you may need to move another one, and the move can cascade until you find a combination of placement that is better.
Patrice
“Everything should be made as simple as possible, but no simpler.” Albert Einstein
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BestFit:
Minimize: Item.Length*Bin.Width*Bin.Height
Subject To: Bin.RemainWeight>=Item.Weight & Bin.RemainLength>=Item.Length
___________________
Right,
I Don't know when must replace Items in Bins
so I need an algorithm
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Does this make sense? Shouldn't we just minimize the total amount of bin-space?
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Right,
It has a similar meaning:
"We should maximize the total used amount of bin-space and maximize the used amount of bin-weight-capacity"
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I think your problem is a cross between a few problems:
- it is similar to the knapsack problem with Multiple constraints
https://en.wikipedia.org/wiki/Knapsack_problem[^]
- It is similar to the cutting stock problem with real stock and where the cut don't go back in stock.
And certainly a few others.
What is important is that they are all NP-Hard problems.
Starting from there your optimisation program is more or less a tree exploration program.
On each step, you try to place a packet in the warehouse, if you find a place, go to next packet, otherwise, if you fail to find a place, you backtrack to move previous packet until you success.
To reduce computing time, you sort packets by difficulty to place, starting by the most difficult.
The base of your program will be a recursive tree exploration program.
By the way, your program will fail when a difficult packet comes and the only place is already in use, in this case, you have to backtrack.
Patrice
“Everything should be made as simple as possible, but no simpler.” Albert Einstein
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Strict alternation (using a variable turn that can take the values 0 or 1) can be used to enforce mutual exclusion among two processes p0 and p1.
A. Generalize the idea to get a procedure for mutual exclusion among n processes p0 through
pn−1.
B. Generalize further, to create a procedure for l-exclusion, where n > l ≥ 2.
For both of the above, write suitable pseudocode, and prove if the three desired properties are satisfied with it
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This sounds like homework. Which I am afraid to say that you wont get anyone answering that for you.
People will help you with your homework if you show the work that you have done and give a detailed explanation of what you are expecting the code to do (and not to repeat the homework) and what is happening.
Every day, thousands of innocent plants are killed by vegetarians.
Help end the violence EAT BACON
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It is actually not a homework. I am trying to apply classic distributed algorithms in a peer-to-peer n player mobile game where each player plays only with one of the players who hasn't already lost in an earlier round to another player. A player who has lost waits until last player wins against runner-up , at which time all players are back in game, until then they need play proxy games with any other lost player to improve skills and ranking, but not get any points when the tournament restarts.
When there are is any player playing in tournament, the code looks like this :
for process i
while( 1)
{
while( games[i/2] != 0){}
enter criticalsection and play game;
games[i/2] <- 1; //assign to other player
//after m such rounds, if score of I is > score of I+1, I wins, else I+1 wins. But my challenge is winner set array should be accessible by only one of n processes.
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You could have explained that in the first place in a single question, rather than the three you posted.
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I thought splitting into three discrete smaller problems would help get focused sharper suggestions. Thanks for pointing out
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