Peter Alfeld Department of Mathematics College of Science University of Utah The Bernstein Bézier Form Home Page Examples Spline Spaces and Minimal Determining Sets User's Guide Residual Arithmetic Triangulations How does it work? Bibliography

Residual Arithmetic, r=3, d=10

The following table illustrates the performance of residual arithmetic. The dimension of the spline space on the generic double Clough-Tocher split, for r=3 and d=10 is 184. It was computed using three consecutive prime numbers. The table gives the top one of those prime numbers, and the color indicates the result, as follows:

•  Red:
All entries in the linear system have at least one of their residuals equal to zero. This makes Gaussian Elimination impossible and the matrix is considered to have rank 0.
•  Purple:
The computed dimension is too high. Some non-zero numbers in the linear system are treated as being zero.
•  Cyan:
The dimension is computed correctly. However, some entries in the linear systems have a mixture of zero and non-zero residuals. The program recognizes this as a potential problem. Numbers with mixed residuals are considered non-zero, but they cannot serve as pivots.
•  Green:
The dimension is computed correctly and all non-zero entries in the linear system have three non-zero residuals. This is the expected and desired situation. The smallest triple of primes having these properties are 2423, 2437, 2441.
 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 101 103 107 109 113 127 131 137 139 149 151 157 163 167 173 179 181 191 193 197 199 211 223 227 229 233 239 241 251 257 263 269 271 277 281 283 293 307 311 313 317 331 337 347 349 353 359 367 373 379 383 389 397 401 409 419 421 431 433 439 443 449 457 461 463 467 479 487 491 499 503 509 521 523 541 547 557 563 569 571 577 587 593 599 601 607 613 617 619 631 641 643 647 653 659 661 673 677 683 691 701 709 719 727 733 739 743 751 757 761 769 773 787 797 809 811 821 823 827 829 839 853 857 859 863 877 881 883 887 907 911 919 929 937 941 947 953 967 971 977 983 991 997 1009 1013 1019 1021 1031 1033 1039 1049 1051 1061 1063 1069 1087 1091 1093 1097 1103 1109 1117 1123 1129 1151 1153 1163 1171 1181 1187 1193 1201 1213 1217 1223 1229 1231 1237 1249 1259 1277 1279 1283 1289 1291 1297 1301 1303 1307 1319 1321 1327 1361 1367 1373 1381 1399 1409 1423 1427 1429 1433 1439 1447 1451 1453 1459 1471 1481 1483 1487 1489 1493 1499 1511 1523 1531 1543 1549 1553 1559 1567 1571 1579 1583 1597 1601 1607 1609 1613 1619 1621 1627 1637 1657 1663 1667 1669 1693 1697 1699 1709 1721 1723 1733 1741 1747 1753 1759 1777 1783 1787 1789 1801 1811 1823 1831 1847 1861 1867 1871 1873 1877 1879 1889 1901 1907 1913 1931 1933 1949 1951 1973 1979 1987 1993 1997 1999 2003 2011 2017 2027 2029 2039 2053 2063 2069 2081 2083 2087 2089 2099 2111 2113 2129 2131 2137 2141 2143 2153 2161 2179 2203 2207 2213 2221 2237 2239 2243 2251 2267 2269 2273 2281 2287 2293 2297 2309 2311 2333 2339 2341 2347 2351 2357 2371 2377 2381 2383 2389 2393 2399 2411 2417 2423 2437 2441 2447 2459 2467 2473 2477 2503 2521 2531 2539 2543 2549 2551 2557 2579 2591 2593 2609 2617 2621 2633 2647 2657 2659 2663 2671 2677 2683 2687 2689 2693 2699 2707 2711 2713 2719 2729 2731 2741 2749 2753 2767 2777 2789 2791 2797 2801 2803 2819 2833 2837 2843 2851 2857 2861 2879 2887 2897 2903 2909 2917 2927 2939 2953 2957 2963 2969 2971 2999 3001 3011 3019 3023 3037 3041 3049 3061 3067 3079 3083 3089 3109 3119 3121 3137 3163 3167 3169 3181 3187 3191 3203 3209 3217 3221 3229 3251 3253 3257 3259 3271 3299 3301 3307 3313 3319 3323 3329 3331 3343 3347 3359 3361 3371 3373 3389 3391 3407 3413 3433 3449 5003 5009 5011 5021 5023 5039 5051 5059 5077 5081 5087 5099 5101 5107 5113 5119 5147 5153 5167 5171 10007 10009 10037 10039 10061 10067 10069 10079 10091 10093 10099 10103 10111 10133 10139 10141 10151 10159 10163 10169 20011 20021 20023 20029 20047 20051 20063 20071 20089 20101 20107 20113 20117 20123 20129 20143 20147 20149 20161 20173 40009 40013 40031 40037 40039 40063 40087 40093 40099 40111 40123 40127 40129 40151 40153 40163 40169 40177 40189 40193 80021 80039 80051 80071 80077 80107 80111 80141 80147 80149 80153 80167 80173 80177 80191 80207 80209 80221 80231 80233 160001 160009 160019 160031 160033 160049 160073 160079 160081 160087 160091 160093 160117 160141 160159 160163 160169 160183 160201 160207 320009 320011 320027 320039 320041 320053 320057 320063 320081 320083 320101 320107 320113 320119 320141 320143 320149 320153 320179 320209 640007 640009 640019 640027 640039 640043 640049 640061 640069 640099 640109 640121 640127 640139 640151 640153 640163 640193 640219 640223 1000003 1000033 1000037 1000039 1000081 1000099 1000117 1000121 1000133 1000151 1000159 1000171 1000183 1000187 1000193 1000199 1000211 1000213 1000231 1000249

Notes

• The Table contains all primes through 3449, and selected ranges of larger primes.
• The linear system being analyzed comprises 324 equations in 448 variables. Its rank is 282.
• It's not surprising that for the small prime numbers illustrated in the table the computed dimension is not always correct.
• On the other hand, note that the dimension is often computed correctly even though the residuals suggest that there is a problem.
• For large prime numbers the residuals are all non-zero, as one would expect.
• It is remarkable that the primes for which the dimension is overestimated occur in blocks.

[15-Mar-1999]