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◆ test_median_robustness()

static void test_median_robustness ( void  )
static

Definition at line 1475 of file cu_algorithm.c.

1476 {
1477  /* A simple implementation of Weiszfeld's algorithm will fail if the median is equal
1478  * to any one of the inputs, during any iteration of the algorithm.
1479  *
1480  * Because the algorithm uses the centroid as a starting point, this situation will
1481  * occur in the test case below.
1482  */
1483  do_median_test("MULTIPOINT ((0 -1), (0 0), (0 1))", "POINT (0 0)", LW_TRUE, 1000);
1484 
1485  /* Same as above but 3D, and shifter */
1486  do_median_test("MULTIPOINT ((1 -1 3), (1 0 2), (2 1 1))", "POINT (1 0 2)", LW_TRUE, 1000);
1487 
1488  /* Starting point is duplicated */
1489  do_median_test("MULTIPOINT ((0 -1), (0 0), (0 0), (0 1))", "POINT (0 0)", LW_TRUE, 1000);
1490 
1491  /* Cube */
1492  do_median_test("MULTIPOINT ((10 10 10), (10 20 10), (20 10 10), (20 20 10), (10 10 20), (10 20 20), (20 10 20), (20 20 20))",
1493  "POINT (15 15 15)", LW_TRUE, 1000);
1494 
1495  /* Some edge cases */
1496  do_median_test("POINT (7 6)", "POINT (7 6)", LW_TRUE, 1000);
1497  do_median_test("POINT (7 6 2)", "POINT (7 6 2)", LW_TRUE, 1000);
1498  do_median_test("MULTIPOINT ((7 6 2), EMPTY)", "POINT (7 6 2)", LW_TRUE, 1000);
1499 
1500  /* Empty input */
1501  do_median_test("MULTIPOINT EMPTY", "POINT EMPTY", LW_FALSE, 1000);
1502  do_median_test("MULTIPOINT (EMPTY)", "POINT EMPTY", LW_FALSE, 1000);
1503  do_median_test("MULTIPOINT EMPTY", "POINT EMPTY", LW_TRUE, 1000);
1504  do_median_test("MULTIPOINT (EMPTY)", "POINT EMPTY", LW_TRUE, 1000);
1505  do_median_test("MULTIPOINT ZM (1 -1 3 1, 1 0 2 7, 2 1 1 1, EMPTY)", "POINT (1 0 2)", LW_TRUE, 1000);
1506 
1507  /* Weighted input */
1508  do_median_test("MULTIPOINT ZM (1 -1 3 1, 1 0 2 7, 2 1 1 1)", "POINT (1 0 2)", LW_TRUE, 1000);
1509  do_median_test("MULTIPOINT ZM (-1 1 -3 1, -1 0 -2 7, -2 -1 -1 1)", "POINT (-1 0 -2)", LW_TRUE, 1000);
1510  do_median_test("MULTIPOINT ZM (-1 1 -3 1, -1 0 -2 7, -2 -1 -1 0.5, -2 -1 -1 0.5)", "POINT (-1 0 -2)", LW_TRUE, 1000);
1511 
1512  /* Point that is replaced by two half-weighted */
1513  do_median_test("MULTIPOINT ZM ((0 -1 0 1), (0 0 0 1), (0 1 0 0.5), (0 1 0 0.5))", "POINT (0 0 0)", LW_TRUE, 1000);
1514  /* Point is doubled and then erased by negative weight */
1515  do_median_test("MULTIPOINT ZM ((1 -1 3 1), (1 0 2 7), (2 1 1 2), (2 1 1 -1))", NULL, LW_TRUE, 1000);
1516  do_median_test("MULTIPOINT ZM ((1 -1 3 1), (1 0 2 7), (2 1 1 2), (2 1 1 -1))", NULL, LW_FALSE, 1000);
1517  /* Weightless input won't converge */
1518  do_median_test("MULTIPOINT ZM ((0 -1 0 0), (0 0 0 0), (0 0 0 0), (0 1 0 0))", NULL, LW_FALSE, 1000);
1519  do_median_test("MULTIPOINT ZM ((0 -1 0 0), (0 0 0 0), (0 0 0 0), (0 1 0 0))", NULL, LW_TRUE, 1000);
1520  /* Negative weight won't converge */
1521  do_median_test("MULTIPOINT ZM ((0 -1 0 -1), (0 0 0 -1), (0 1 0 -1))", NULL, LW_FALSE, 1000);
1522  do_median_test("MULTIPOINT ZM ((0 -1 0 -1), (0 0 0 -1), (0 1 0 -1))", NULL, LW_TRUE, 1000);
1523 
1524  /* Bind convergence too tightly */
1525  do_median_test("MULTIPOINT ((0 0), (1 1), (0 1), (2 2))", "POINT(0.75 1.0)", LW_FALSE, 0);
1526  do_median_test("MULTIPOINT ((0 0), (1 1), (0 1), (2 2))", NULL, LW_TRUE, 1);
1527  /* Unsupported geometry type */
1528  do_median_test("POLYGON((1 0,0 1,1 2,2 1,1 0))", NULL, LW_TRUE, 1000);
1529  do_median_test("POLYGON((1 0,0 1,1 2,2 1,1 0))", NULL, LW_FALSE, 1000);
1530 
1531  /* Median point is included */
1532  do_median_test("MULTIPOINT ZM ("
1533  "(1480 0 200 100),"
1534  "(620 0 200 100),"
1535  "(1000 0 -200 100),"
1536  "(1000 0 -590 100),"
1537  "(1025 0 65 100),"
1538  "(1025 0 -65 100)"
1539  ")",
1540  "POINT (1025 0 -65)", LW_TRUE, 10000);
1541 
1542 #if 0
1543  /* Leads to invalid result (0 0 0) with 80bit (fmulp + faddp) precision. ok with 64 bit float ops */
1544  do_median_test("MULTIPOINT ZM ("
1545  "(0 0 20000 0.5),"
1546  "(0 0 59000 0.5),"
1547  "(0 -3000 -3472.22222222222262644208967685699462890625 1),"
1548  "(0 3000 3472.22222222222262644208967685699462890625 1),"
1549  "(0 0 -1644.736842105263121993630193173885345458984375 1),"
1550  "(0 0 1644.736842105263121993630193173885345458984375 1),"
1551  "(0 48000 -20000 1.3),"
1552  "(0 -48000 -20000 1.3)"
1553  ")",
1554  "POINT (0 0 0)", LW_TRUE, 10000);
1555 #endif
1556 
1557 #if 0
1558  /* Leads to invalid result (0 0 0) with 64bit (vfmadd231sd) precision. Ok with 80 bit float ops */
1559  do_median_test("MULTIPOINT ZM ("
1560  "(0 0 20000 0.5),"
1561  "(0 0 59000 0.5),"
1562  "(0 -3000 -3472.22222222222262644208967685699462890625 1),"
1563  "(0 3000 3472.22222222222262644208967685699462890625 1),"
1564  "(0 -0.00000000000028047739569477638384522295466033823196 -1644.736842105263121993630193173885345458984375 1),"
1565  "(0 0.00000000000028047739569477638384522295466033823196 1644.736842105263121993630193173885345458984375 1),"
1566  "(0 48000 -20000 1.3),"
1567  "(0 -48000 -20000 1.3)"
1568  ")",
1569  "POINT (0 0 0)", LW_TRUE, 10000);
1570 #endif
1571 }
static void do_median_test(char *input, char *expected, int fail_if_not_converged, int iter_count)
#define LW_FALSE
Definition: liblwgeom.h:108
#define LW_TRUE
Return types for functions with status returns.
Definition: liblwgeom.h:107

References do_median_test(), LW_FALSE, and LW_TRUE.

Referenced by algorithms_suite_setup().

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