UNBOUNDED-PROBLEM-ERROR raised for bounded problem.

[lispmac]

Hi,

I'm trying to solve the Stigler Diet problem using this library. For the definition of the problem as well as the code in Python, please see https://developers.google.com/optimization/lp/glop

I'm using the 2019-11-30 version of this library from Quicklisp.

When I try to run the code below, the error UNBOUNDED-PROBLEM-ERROR is signaled. Am I defining the problem incorrectly?

(defparameter data
  '(("Wheat Flour (Enriched)" "10 lb." 36 44.7 1411 2 365 0 55.4 33.3 441 0)
    ("Macaroni" "1 lb." 14.1 11.6 418 0.7 54 0 3.2 1.9 68 0)
    ("Wheat Cereal (Enriched)" "28 oz." 24.2 11.8 377 14.4 175 0 14.4 8.8 114 0)
    ("Corn Flakes" "8 oz." 7.1 11.4 252 0.1 56 0 13.5 2.3 68 0)
    ("Corn Meal" "1 lb." 4.6 36.0 897 1.7 99 30.9 17.4 7.9 106 0)
    ("Hominy Grits" "24 oz." 8.5 28.6 680 0.8 80 0 10.6 1.6 110 0)
    ("Rice" "1 lb." 7.5 21.2 460 0.6 41 0 2 4.8 60 0)
    ("Rolled Oats" "1 lb." 7.1 25.3 907 5.1 341 0 37.1 8.9 64 0)
    ("White Bread (Enriched)" "1 lb." 7.9 15.0 488 2.5 115 0 13.8 8.5 126 0)
    ("Whole Wheat Bread" "1 lb." 9.1 12.2 484 2.7 125 0 13.9 6.4 160 0)
    ("Rye Bread" "1 lb." 9.1 12.4 439 1.1 82 0 9.9 3 66 0)
    ("Pound Cake" "1 lb." 24.8 8.0 130 0.4 31 18.9 2.8 3 17 0)
    ("Soda Crackers" "1 lb." 15.1 12.5 288 0.5 50 0 0 0 0 0)
    ("Milk" "1 qt." 11 6.1 310 10.5 18 16.8 4 16 7 177)
    ("Evaporated Milk (can)" "14.5 oz." 6.7 8.4 422 15.1 9 26 3 23.5 11 60)
    ("Butter" "1 lb." 30.8 10.8 9 0.2 3 44.2 0 0.2 2 0)
    ("Oleomargarine" "1 lb." 16.1 20.6 17 0.6 6 55.8 0.2 0 0 0)
    ("Eggs" "1 doz." 32.6 2.9 238 1.0 52 18.6 2.8 6.5 1 0)
    ("Cheese (Cheddar)" "1 lb." 24.2 7.4 448 16.4 19 28.1 0.8 10.3 4 0)
    ("Cream" "1/2 pt." 14.1 3.5 49 1.7 3 16.9 0.6 2.5 0 17)
    ("Peanut Butter" "1 lb." 17.9 15.7 661 1.0 48 0 9.6 8.1 471 0)
    ("Mayonnaise" "1/2 pt." 16.7 8.6 18 0.2 8 2.7 0.4 0.5 0 0)
    ("Crisco" "1 lb." 20.3 20.1 0 0 0 0 0 0 0 0)
    ("Lard" "1 lb." 9.8 41.7 0 0 0 0.2 0 0.5 5 0)
    ("Sirloin Steak" "1 lb." 39.6 2.9 166 0.1 34 0.2 2.1 2.9 69 0)
    ("Round Steak" "1 lb." 36.4 2.2 214 0.1 32 0.4 2.5 2.4 87 0)
    ("Rib Roast" "1 lb." 29.2 3.4 213 0.1 33 0 0 2 0 0)
    ("Chuck Roast" "1 lb." 22.6 3.6 309 0.2 46 0.4 1 4 120 0)
    ("Plate" "1 lb." 14.6 8.5 404 0.2 62 0 0.9 0 0 0)
    ("Liver (Beef)" "1 lb." 26.8 2.2 333 0.2 139 169.2 6.4 50.8 316 525)
    ("Leg of Lamb" "1 lb." 27.6 3.1 245 0.1 20 0 2.8 3.9 86 0)
    ("Lamb Chops (Rib)" "1 lb." 36.6 3.3 140 0.1 15 0 1.7 2.7 54 0)
    ("Pork Chops" "1 lb." 30.7 3.5 196 0.2 30 0 17.4 2.7 60 0)
    ("Pork Loin Roast" "1 lb." 24.2 4.4 249 0.3 37 0 18.2 3.6 79 0)
    ("Bacon" "1 lb." 25.6 10.4 152 0.2 23 0 1.8 1.8 71 0)
    ("Ham smoked" "1 lb." 27.4 6.7 212 0.2 31 0 9.9 3.3 50 0)
    ("Salt Pork" "1 lb." 16 18.8 164 0.1 26 0 1.4 1.8 0 0)
    ("Roasting Chicken" "1 lb." 30.3 1.8 184 0.1 30 0.1 0.9 1.8 68 46)
    ("Veal Cutlets" "1 lb." 42.3 1.7 156 0.1 24 0 1.4 2.4 57 0)
    ("Salmon Pink (can)" "16 oz." 13 5.8 705 6.8 45 3.5 1 4.9 209 0)
    ("Apples" "1 lb." 4.4 5.8 27 0.5 36 7.3 3.6 2.7 5 544)
    ("Bananas" "1 lb." 6.1 4.9 60 0.4 30 17.4 2.5 3.5 28 498)
    ("Lemons" "1 doz." 26 1.0 21 0.5 14 0 0.5 0 4 952)
    ("Oranges" "1 doz." 30.9 2.2 40 1.1 18 11.1 3.6 1.3 10 1998)
    ("Green Beans" "1 lb." 7.1 2.4 138 3.7 80 69 4.3 5.8 37 862)
    ("Cabbage" "1 lb." 3.7 2.6 125 4.0 36 7.2 9 4.5 26 5369)
    ("Carrots" "1 bunch" 4.7 2.7 73 2.8 43 188.5 6.1 4.3 89 608)
    ("Celery" "1 stalk" 7.3 0.9 51 3.0 23 0.9 1.4 1.4 9 313)
    ("Lettuce" "1 head" 8.2 0.4 27 1.1 22 112.4 1.8 3.4 11 449)
    ("Onions" "1 lb." 3.6 5.8 166 3.8 59 16.6 4.7 5.9 21 1184)
    ("Potatoes" "15 lb." 34 14.3 336 1.8 118 6.7 29.4 7.1 198 2522)
    ("Spinach" "1 lb." 8.1 1.1 106 0 138 918.4 5.7 13.8 33 2755)
    ("Sweet Potatoes" "1 lb." 5.1 9.6 138 2.7 54 290.7 8.4 5.4 83 1912)
    ("Peaches (can)" "No. 2 1/2" 16.8 3.7 20 0.4 10 21.5 0.5 1 31 196)
    ("Pears (can)" "No. 2 1/2" 20.4 3.0 8 0.3 8 0.8 0.8 0.8 5 81)
    ("Pineapple (can)" "No. 2 1/2" 21.3 2.4 16 0.4 8 2 2.8 0.8 7 399)
    ("Asparagus (can)" "No. 2" 27.7 0.4 33 0.3 12 16.3 1.4 2.1 17 272)
    ("Green Beans (can)" "No. 2" 10 1.0 54 2 65 53.9 1.6 4.3 32 431)
    ("Pork and Beans (can)" "16 oz." 7.1 7.5 364 4 134 3.5 8.3 7.7 56 0)
    ("Corn (can)" "No. 2" 10.4 5.2 136 0.2 16 12 1.6 2.7 42 218)
    ("Peas (can)" "No. 2" 13.8 2.3 136 0.6 45 34.9 4.9 2.5 37 370)
    ("Tomatoes (can)" "No. 2" 8.6 1.3 63 0.7 38 53.2 3.4 2.5 36 1253)
    ("Tomato Soup (can)" "10 1/2 oz." 7.6 1.6 71 0.6 43 57.9 3.5 2.4 67 862)
    ("Peaches Dried" "1 lb." 15.7 8.5 87 1.7 173 86.8 1.2 4.3 55 57)
    ("Prunes Dried" "1 lb." 9 12.8 99 2.5 154 85.7 3.9 4.3 65 257)
    ("Raisins Dried" "15 oz." 9.4 13.5 104 2.5 136 4.5 6.3 1.4 24 136)
    ("Peas Dried" "1 lb." 7.9 20.0 1367 4.2 345 2.9 28.7 18.4 162 0)
    ("Lima Beans Dried" "1 lb." 8.9 17.4 1055 3.7 459 5.1 26.9 38.2 93 0)
    ("Navy Beans Dried" "1 lb." 5.9 26.9 1691 11.4 792 0 38.4 24.6 217 0)
    ("Coffee" "1 lb." 22.4 0 0 0 0 0 4 5.1 50 0)
    ("Tea" "1/4 lb." 17.4 0 0 0 0 0 0 2.3 42 0)
    ("Cocoa" "8 oz." 8.6 8.7 237 3 72 0 2 11.9 40 0)
    ("Chocolate" "8 oz." 16.2 8.0 77 1.3 39 0 0.9 3.4 14 0)
    ("Sugar" "10 lb." 51.7 34.9 0 0 0 0 0 0 0 0)
    ("Corn Syrup" "24 oz." 13.7 14.7 0 0.5 74 0 0 0 5 0)
    ("Molasses" "18 oz." 13.6 9.0 0 10.3 244 0 1.9 7.5 146 0)
    ("Strawberry Preserves" "1 lb." 20.5 6.4 11 0.4 7 0.2 0.2 0.4 3 0)))

(defparameter nutrients
  '(("Calories (1000s)" 3)
    ("Protein (grams)" 70)
    ("Calcium (grams)" 0.8)
    ("Iron (mg)" 12)
    ("Vitamin A (1000 IU)" 5)
    ("Vitamin B1 (mg)" 1.8)
    ("Vitamin B2 (mg)" 2.7)
    ("Niacin (mg)" 18)
    ("Vitamin C (mg)" 75)))

(defparameter objective-function
 `(min (= w (+ ,@(mapcar 'make-symbol (mapcar 'first data))))))

(defparameter constraints
  (let ((constraints (list)))
    (do ((i 0 (1+ i)))
        ((= i (length nutrients)) i)
      (push `(<= ,(second (nth i nutrients))
                 (+ ,@(mapcar (lambda (d) `(* ,(nth (+ i 3) d)
                                              ,(make-symbol (first d)))) data)))
            constraints))
    constraints))

(defparameter problem
  (parse-linear-problem
   objective-function
   constraints))

(defparameter solution
  (solve-problem problem))

[neil-lindquist]

As far as I can tell, your definition is correct, so this is likely a bug.
Is it thrown from solving the problem or parsing the problem?

As a side note, you can format multi-line blocks of code by wrapping them in triple backquotes. For example,

`` `
Lisp code here
`` `

[lispmac]

Thanks! The error is signaled from solving the problem.

[neil-lindquist]

I had a chance to look at this, and it's an issue with floating point error causing a check to fail. I've increased the tolerance for round off error a little bit in that check. So, you can download the new version either from Ultralisp or Github directly, and your code should work.
Alternatively, if all of the values are rationals instead of floats, it should also work.

Thanks for bringing this to my attention (plus another bug that I found while debugging). Let me know if it's still failing.