Frequently Asked Questions
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How is the site organized?
The site consists of three main parts: Setup, the Workshop, and the Workbench. The Workbench is where you work directly on a formula. The Workshop contains tools you might need from time to time, but not every time you work on a formula (such as the list of ingredients, or the formula defaults). The Setup area is for items you change only rarely, but may need some expert work when your installation is first set up. When you first log in the site you go in to the Workshop. There you see a list of the formulas that already exist. You can create a new formula or click on an existing one to work on. When you do that, you go into the Workbench.
How do I get to the Workbench?
From the Workshop click on the name of any formula. If you leave the Workbench', having visited at least one formula, the Workbench' tab will bring you back into the formula you were last working on.
I’m in the Workbench. How do I change the current formula to another formula?
The formula name is a drop down box that shows all formulas available at your current level for the species you selected in the Workshop. (If you didn't select a species, then all available formula appear in the dropdown.) You can select another formula and its data will appear. You can also exit the Workbench by selecting the Workshop tab. Then click on the name of the formula that you want to bring you back into the Workbench. To see formulas not visible at your current level you need to change your level to one where the formula can be viewed.
I’m in the Workbench, and I wish to change the cost of an ingredient.
Either change the cost right there on the Formula Ingredients page in the Workbench or click on the name of the ingredient and you'll get to another page where you can also change the cost. Note that the ingredient cost change applies to all formulas at the same control level.
I changed the minimum for Sodium Chloride from 0.250 to 0.260, a little higher than the maximum. After clicking "Update" and "Solve", a message on the upper left screen shows "No Feasible Primal Solution ...".
If a minimum is greater than a maximum, an infeasibility will surely follow. The offending minimum and maximum will be colored as Error: Value prevents feasible solution. And the actual percent may be colored as Warning: Value is out of range.
Can the system be installed on a personal computer ?
Theoretically, yes, but there is no need and the cost is higher. The system requires the appropriate database, browser, web server, and version of Java, all of which need to be installed when the system is installed.
It takes a long time to get a new screen after I hit the solve button.
Typically a formula should solve in less than five seconds. If you are not using a broadband (cable, DSL) connection you may experience a delay. If you use a high-speed connection, please let Customer Service know if you experience unusual delays.
I put ‘S’ into the Log field in the Workbench Full Header screen and I get a whole bunch of messages in the upper left corner.
You are getting statistics after you press the solve button. These include the time of start and end of the request and the time of the start and end of the solve process. The Objective Function is the Total Cost. “Iters” (iterations) is the number of attempts it took to solve or to become infeasible if there is no solution. “NREJ” (number of rejects) reflects the difficulty of solving and normally is zero or a small number.
Note that it takes time to gather all the information together before the program can even begin to solve and additional time after the solve to format the solution.
The messages that appear in the upper left after pressing the solve button are informational or errors. If the solution solves correctly, you get the message “Optimal Solution Reached.” If the formulator cannot find a solution, you get “No feasible primal solution.”
‘S’ in the log field is not needed in running the program normally. To eliminate statistical information, change the ‘S’ back to ‘N’.
How do I add a new ingredient ?
The Ingredients tab is available from anywhere on the site. Click on the Ingredients tab and then on the New Ingredient button.
How do I add a new nutrient ?
You must first go to Setup. If you are in the Setup area, click on the Nutrients tab. Then click on the New Nutrient button.
How do I delete an ingredient, nutrient, or formula ?
On the page that list the type of thing you want to delete (the Ingredients, Nutrients, or Formulas page) a "Delete" button appears in the right hand column if your current Control Level owns the object you want to delete.
How do I get a new nutrient to appear in the Solution Report?
First of all, you need to give a value for the nutrient in at least one ingredient in your formula. Only when the solution contains an ingredient with a value for the new nutrient will the solution have a value for the nutrient.
In the second place, the Solution Report defaults to only those nutrients that are on the short list. You can add a nutrient to the short list for all formulas in a species by going to Species in the Setup area. All nutrients on the species short list are on the short list for the formula. In addition, any nutrient selected (checked) in the formula is also on the formula short list. Nutrients with minimum or maximum restrictions in the formula are automatically checked. Checking a nutrient with no restrictions adds it to the formula short list.
You can also uncheck the "Short List" option when you run the Solution Report. The report will then have a value for every nutrient contributed by every ingredient in the solution.
How do I add a new ratio ?
You must first go to the Workbench' to work on a formula. Click on the Ratios tab and then on the New Ratio button.
What does ‘N’ and ‘I’ mean on the ratios ?
‘N’ denotes a nutrient and ‘I’ denotes an ingredient. A ratio can be between nutrients, ingredients, or an ingredient and a nutrient.
Why do more nutrients or ingredients appear in the solution than I checked off in the formula ?
The Formulator calculates the values for every nutrient found in every ingredient in the solution. If you choose nutrients in ‘In Solution’ all nutrients with values appear, whether they were selected or not. When a ingredient is added to a ratio it is implicitly added to the formula even though it has not been explicitly selected.
How do I add a nutrient or an ingredient to a formula ?
From the Current Selection drop down, pick ‘All for Species’ or ‘Short List’ and select the nutrient or ingredient by clicking the Sel box to add a check mark.
How do I remove a nutrient or an ingredient from a formula ?
Deselect the nutrient or ingredient by clicking the Sel box to remove the check mark.
What is pivot delta ?
Pivot delta is a number that prevents division by zero during the solve process. Suggested values are 0.000001 or 0.0000001, but it can’t be zero! Unless you have a very good reason, don’t change from installed values.
What is equal delta ?
Equal delta is a number that insures a gap between the minimum and maximum constraint. Suggested values are 0.0002 or 0.001. Unless you have a very good reason, don’t change from installed values.
What does Formula Type do ?
Formula Type consists of two unrelated one character alphanumeric fields that the user can assign freely for any identification purpose.
For example, some users put the initial of the owner of a particular formula in one of these so that other users do not modify it without permission from the owner.
What does ‘Opt Den’ mean ?
It means Optimum Density. Optimum Density frees the ration from the batch weight constraint, while making sure that the quantity of nutrients is the same as a fixed batch weight ration. An Optimum Density ration is cheaper per nutrient.
Normally, the program solves for a specified batch weight. To understand Optimum Density, you must first understand that the most important part of the formula is the nutrient specification. In solving for least cost, the optimum weight that satisfies all the nutrient requirements at the lowest cost will almost never be the batch weight.
Optimum Density will increase (or decrease) batch size in order to change the nutrient density. Changing nutrient density is an important tool in feeding under conditions of heat or stress. It also will find the optimum batch size, thus saving an additional amount over fixed batch size least-cost.
To find out what that weight is, change ‘Opt Den’ to Y and click Solve Formula.
To let the computer determine the ideal weight, set the ‘Opt Pct’ to zero. On the other hand, if you want to limit the variance of the optimum density weight with the batch weight, set the ‘Opt Pct’ to, say, 95. Then the optimum weight will be forced to be between 95 and 105% of the batch weight. Setting ‘Opt Pct’ to 100 will have the same result as if ‘Opt Den’ were ‘N’.
What does the Workbench tab do ?
Returns you to the last formula that you used in the Workbench.
If you have not yet been to the Workbench, the program displays a message and invites you to select a formula from the Workshop. Selecting a formula takes you to the Workbench.
If your session times out you will get the message asking you to select a formula, even if you have already picked one.
On the Ingredients page, why do some of the ingredients not have the word 'Formulas' in the Usage column?
Ingredients that don't have the word 'Formulas' are not used in any formula.
The word 'Formulas' is a link to the Ingredient-Formula cross reference page. Only ingredients that are checked in at least one formula have a this link. Clicking on the Formulas link will display a list of all the formulas where the ingredient is checked.
What is the Short List?
The Short List is a group of nutrients or ingredients that you want to use or keep track of more frequently than others. If you create a Species Short List, it will be the default list when you first enter a formula in the Workbench'.
How do I make a Short List?
You construct a Short List under the Species tab in the Setup area. Click on a particular species to assign ingredients or nutrients to the Species Short List.
By default you come to the nutrient list, when you click a species. You can check the nutrients you want to put in the short list there. To add ingredients to the short list, click the Ingredients tab. To get back to the nutrient list, click the Nutrients tab.
Why do more Ingredients (or Nutrients) appear in the Short List in the Workbench than I selected for my Species Ingredient (or Nutrient) Short List?
In the Workbench', the Short List includes both those Ingredients that you have placed on the species Short List and those Ingredients selected for the formula. The same is true of Nutrients.
What does checking a Nutrient in a formula do?
A nutrient must be included in a formula (checked) if it has a constraint (a minimum or maximum). If you specify a minimum or maximum for a nutrient, the nutrient is automatically checked. If you uncheck a nutrient that has a constraint, the constraint will be greyed out and not used in solving the formula. Checking a nutrient that has no constraint adds it to the Short List of the formula, even if it not in the Short List of the species. If you use a nutrient Short List and you typically choose ‘Short List’ when looking at nutrients in a formula, there is no need to check a nutrient that has no minimum or maximum if it is on the Species Short List. If you want to keep track of a nutrient in most formulas, it is better to add the nutrient to the Species Short List than to check it in every formula.
The main value of checking a nutrient that has no constraints and is not on the species short list, is that the nutrient will appear in the Solution Report when 'Use short list for nutrients' is checked.
What does checking an Ingredient in a formula do?
An ingredient must be included in a formula (checked) if it is to be considered for the solution, whether or not it has a constraint (a minimum or maximum). If an ingredient is not checked, the only other way it can be considered in the solution is to add it to a ratio. As with nutrients, if you specify a minimum or maximum for an ingredient, the ingredient is automatically checked. If you uncheck an ingredient that has a constraint, the constraint will be greyed out and the ingredient will not be considered in solving the formula (unless it also appears in a ratio, but in that case the greyed out constraint will be ignored). Checking an ingredient that has no constraint adds it to the Short List of the formula, even if it not in the Short List of the species. If you use an ingredient Short List and you choose the ‘Short List’ when looking at ingredients in a formula, you can easily see which ingredients on your formula Short List end up in the solution and which do not. Remember that, unlike a nutrient, an ingredient must be included in a formula before the Solve Formula process will consider it.
Many pages have a ‘Contains’ button. What does it do?
It lets you search for items by name or code. In the box just to the right of the ‘Contains’ button enter a character string that you wish to search for. Then click the ‘Contains’ button (or anywhere on the page). The program will select only those items whose name (or code) contains the characters you entered. For example, if you are on a page that displays ingredients and are looking for soy ingredients, type the word ‘soy’ in the box and click ‘Contains’. The drop down box to left of the ‘Contains’ button allows you to search for items by either name or code (name is the default). The’ Contains’ button can save you the trouble of scrolling through many pages. For example, if you want to add an ingredient to a formula that is not on your short list, pick ‘All for Species’ to get the list of all available ingredients. Then enter all or part of the name of the ingredient you are looking for in the box and then click ‘Contains’. Remember that the program looks for the search characters anywhere in the name or code. If you key the letter ‘e’ (or any combination of letters that occurs frequently), you are likely to get far more items than you want.
Why does the 'Revert' button appear next to a formula even though I haven't changed anything?
In the Workbench, if you simply look at a formula created at a higher level, the 'Revert' button does not appear. But if you solve the formula at your current level, you may get different results because of ingredient price or nutrient value changes. When you first look at a formula created at a higher level, you will see the results from the level closest to your level where the formula was solved at least once (even though the last solved date does not appear). If you click the 'Solve' button, the results, whether they are the same or different, are stored at your current level and so the 'Revert' button and the last solved date appear. Reverting restores the formula to the condition before you made any changes or clicked the 'Solve' button. Reverting a formula does not undo changes to ingredient costs or nutrient values.
Why do no nutrients appear when I go to the 'Nutrients' section of the Workbench, even if I change the selection drop down to 'All for species'?
Have you checked 'Show changed items only'? If the nutrients were defined at a higher level and you haven't changed any of them, there will be no nutrients in the list.
Uncheck 'Show changed items only' and the nutrients will appear.
