После обновления до версии с открытым исходным кодом Z3 (последняя версия git master) ямы заметили существенную разницу во времени между повторными запусками почти идентичных SMT-запросов с использованием C API (где-то от 2-122 с). Единственная разница между запросами заключается в именовании массивов (в логике QF_AUFBV).

Мы'перераспределяем массивы следующим образом:

Z3_symbol s = Z3_mk_string_symbol(z3_context, arrayName);
Z3_mk_const(z3_context, s,
            Z3_mk_array_sort(z3_context, getSort(32), getSort(8)));

Ниже приведен пример запроса (преобразованный в SMT-LIB). Замена "arr51" с другими именами (например, "а" или же "arr51_0x2628008") значительно изменяет длительность запроса до двух порядков. Повторные запуски без изменения имени массива don 't демонстрируют значительные изменения во времени.

Интересно, что старый бинарный релиз Z3 3.2 неПохоже, что на него влияет наименование массива (и оно работает быстрее для большинства наших запросов).

(benchmark klee
:status unsat
:logic QF_AUFBV
:extrafuns ((arr51 Array[32:8]))
:assumption
(let (?x13 (concat (select arr51 bv58[32]) (concat (select arr51 bv57[32]) (select arr51 bv56[32]))))
(let (?x16 (concat (select arr51 bv59[32]) ?x13))
(let (?x23 (concat bv0[32] ?x16))
(let (?x34 (bvsub (bvadd (concat (extract[33:0] ?x23) bv0[30]) (concat (extract[35:0] ?x23) bv0[28])) (concat (extract[40:0] ?x23) bv0[23])))
(let (?x42 (bvadd (bvadd ?x34 (concat (extract[44:0] ?x23) bv0[19])) (concat (extract[45:0] ?x23) bv0[18])))
(let (?x50 (bvadd (bvsub ?x42 (concat (extract[47:0] ?x23) bv0[16])) (concat (extract[49:0] ?x23) bv0[14])))
(let (?x58 (bvsub (bvadd ?x50 (concat (extract[50:0] ?x23) bv0[13])) (concat (extract[52:0] ?x23) bv0[11])))
(let (?x66 (bvadd (bvadd ?x58 (concat (extract[56:0] ?x23) bv0[7])) (concat (extract[59:0] ?x23) bv0[4])))
(let (?x68 (extract[63:32] (bvsub ?x66 ?x23)))
(flet ($x79 (= bv1[32] bv30[32]))
(let (?x80 (ite $x79 (concat bv0[30] (extract[31:30] (bvsub ?x16 ?x68))) (ite (= bv1[32] bv31[32]) (concat bv0[31] (extract[31:31] (bvsub ?x16 ?x68))) bv0[32])))
(flet ($x85 (= bv1[32] bv29[32]))
(flet ($x90 (= bv1[32] bv28[32]))
(let (?x91 (ite $x90 (concat bv0[28] (extract[31:28] (bvsub ?x16 ?x68))) (ite $x85 (concat bv0[29] (extract[31:29] (bvsub ?x16 ?x68))) ?x80)))
(flet ($x96 (= bv1[32] bv27[32]))
(flet ($x102 (= bv1[32] bv26[32]))
(let (?x103 (ite $x102 (concat bv0[26] (extract[31:26] (bvsub ?x16 ?x68))) (ite $x96 (concat bv0[27] (extract[31:27] (bvsub ?x16 ?x68))) ?x91)))
(flet ($x108 (= bv1[32] bv25[32]))
(flet ($x114 (= bv1[32] bv24[32]))
(let (?x115 (ite $x114 (concat bv0[24] (extract[31:24] (bvsub ?x16 ?x68))) (ite $x108 (concat bv0[25] (extract[31:25] (bvsub ?x16 ?x68))) ?x103)))
(flet ($x119 (= bv1[32] bv23[32]))
(flet ($x125 (= bv1[32] bv22[32]))
(let (?x126 (ite $x125 (concat bv0[22] (extract[31:22] (bvsub ?x16 ?x68))) (ite $x119 (concat bv0[23] (extract[31:23] (bvsub ?x16 ?x68))) ?x115)))
(flet ($x131 (= bv1[32] bv21[32]))
(flet ($x137 (= bv1[32] bv20[32]))
(let (?x138 (ite $x137 (concat bv0[20] (extract[31:20] (bvsub ?x16 ?x68))) (ite $x131 (concat bv0[21] (extract[31:21] (bvsub ?x16 ?x68))) ?x126)))
(flet ($x142 (= bv1[32] bv19[32]))
(flet ($x147 (= bv1[32] bv18[32]))
(let (?x148 (ite $x147 (concat bv0[18] (extract[31:18] (bvsub ?x16 ?x68))) (ite $x142 (concat bv0[19] (extract[31:19] (bvsub ?x16 ?x68))) ?x138)))
(flet ($x153 (= bv1[32] bv17[32]))
(flet ($x157 (= bv1[32] bv16[32]))
(let (?x158 (ite $x157 (concat bv0[16] (extract[31:16] (bvsub ?x16 ?x68))) (ite $x153 (concat bv0[17] (extract[31:17] (bvsub ?x16 ?x68))) ?x148)))
(flet ($x163 (= bv1[32] bv15[32]))
(flet ($x168 (= bv1[32] bv14[32]))
(let (?x169 (ite $x168 (concat bv0[14] (extract[31:14] (bvsub ?x16 ?x68))) (ite $x163 (concat bv0[15] (extract[31:15] (bvsub ?x16 ?x68))) ?x158)))
(flet ($x173 (= bv1[32] bv13[32]))
(flet ($x179 (= bv1[32] bv12[32]))
(let (?x180 (ite $x179 (concat bv0[12] (extract[31:12] (bvsub ?x16 ?x68))) (ite $x173 (concat bv0[13] (extract[31:13] (bvsub ?x16 ?x68))) ?x169)))
(flet ($x184 (= bv1[32] bv11[32]))
(flet ($x190 (= bv1[32] bv10[32]))
(let (?x191 (ite $x190 (concat bv0[10] (extract[31:10] (bvsub ?x16 ?x68))) (ite $x184 (concat bv0[11] (extract[31:11] (bvsub ?x16 ?x68))) ?x180)))
(flet ($x196 (= bv1[32] bv9[32]))
(flet ($x202 (= bv1[32] bv8[32]))
(let (?x203 (ite $x202 (concat bv0[8] (extract[31:8] (bvsub ?x16 ?x68))) (ite $x196 (concat bv0[9] (extract[31:9] (bvsub ?x16 ?x68))) ?x191)))
(flet ($x207 (= bv1[32] bv7[32]))
(flet ($x213 (= bv1[32] bv6[32]))
(let (?x214 (ite $x213 (concat bv0[6] (extract[31:6] (bvsub ?x16 ?x68))) (ite $x207 (concat bv0[7] (extract[31:7] (bvsub ?x16 ?x68))) ?x203)))
(flet ($x219 (= bv1[32] bv5[32]))
(flet ($x224 (= bv1[32] bv4[32]))
(let (?x225 (ite $x224 (concat bv0[4] (extract[31:4] (bvsub ?x16 ?x68))) (ite $x219 (concat bv0[5] (extract[31:5] (bvsub ?x16 ?x68))) ?x214)))
(flet ($x230 (= bv1[32] bv3[32]))
(flet ($x236 (= bv1[32] bv2[32]))
(let (?x237 (ite $x236 (concat bv0[2] (extract[31:2] (bvsub ?x16 ?x68))) (ite $x230 (concat bv0[3] (extract[31:3] (bvsub ?x16 ?x68))) ?x225)))
(flet ($x241 (= bv1[32] bv1[32]))
(let (?x69 (bvsub ?x16 ?x68))
(flet ($x243 (= bv1[32] bv0[32]))
(let (?x245 (bvadd (ite $x243 ?x69 (ite $x241 (concat bv0[1] (extract[31:1] ?x69)) ?x237)) ?x68))
(let (?x253 (ite (= bv16[32] bv30[32]) (concat bv0[30] (extract[31:30] ?x245)) (ite (= bv16[32] bv31[32]) (concat bv0[31] (extract[31:31] ?x245)) bv0[32])))
(let (?x261 (ite (= bv16[32] bv28[32]) (concat bv0[28] (extract[31:28] ?x245)) (ite (= bv16[32] bv29[32]) (concat bv0[29] (extract[31:29] ?x245)) ?x253)))
(let (?x269 (ite (= bv16[32] bv26[32]) (concat bv0[26] (extract[31:26] ?x245)) (ite (= bv16[32] bv27[32]) (concat bv0[27] (extract[31:27] ?x245)) ?x261)))
(let (?x277 (ite (= bv16[32] bv24[32]) (concat bv0[24] (extract[31:24] ?x245)) (ite (= bv16[32] bv25[32]) (concat bv0[25] (extract[31:25] ?x245)) ?x269)))
(let (?x285 (ite (= bv16[32] bv22[32]) (concat bv0[22] (extract[31:22] ?x245)) (ite (= bv16[32] bv23[32]) (concat bv0[23] (extract[31:23] ?x245)) ?x277)))
(let (?x293 (ite (= bv16[32] bv20[32]) (concat bv0[20] (extract[31:20] ?x245)) (ite (= bv16[32] bv21[32]) (concat bv0[21] (extract[31:21] ?x245)) ?x285)))
(let (?x301 (ite (= bv16[32] bv18[32]) (concat bv0[18] (extract[31:18] ?x245)) (ite (= bv16[32] bv19[32]) (concat bv0[19] (extract[31:19] ?x245)) ?x293)))
(let (?x309 (ite (= bv16[32] bv16[32]) (concat bv0[16] (extract[31:16] ?x245)) (ite (= bv16[32] bv17[32]) (concat bv0[17] (extract[31:17] ?x245)) ?x301)))
(let (?x317 (ite (= bv16[32] bv14[32]) (concat bv0[14] (extract[31:14] ?x245)) (ite (= bv16[32] bv15[32]) (concat bv0[15] (extract[31:15] ?x245)) ?x309)))
(let (?x325 (ite (= bv16[32] bv12[32]) (concat bv0[12] (extract[31:12] ?x245)) (ite (= bv16[32] bv13[32]) (concat bv0[13] (extract[31:13] ?x245)) ?x317)))
(let (?x333 (ite (= bv16[32] bv10[32]) (concat bv0[10] (extract[31:10] ?x245)) (ite (= bv16[32] bv11[32]) (concat bv0[11] (extract[31:11] ?x245)) ?x325)))
(let (?x341 (ite (= bv16[32] bv8[32]) (concat bv0[8] (extract[31:8] ?x245)) (ite (= bv16[32] bv9[32]) (concat bv0[9] (extract[31:9] ?x245)) ?x333)))
(let (?x349 (ite (= bv16[32] bv6[32]) (concat bv0[6] (extract[31:6] ?x245)) (ite (= bv16[32] bv7[32]) (concat bv0[7] (extract[31:7] ?x245)) ?x341)))
(let (?x357 (ite (= bv16[32] bv4[32]) (concat bv0[4] (extract[31:4] ?x245)) (ite (= bv16[32] bv5[32]) (concat bv0[5] (extract[31:5] ?x245)) ?x349)))
(let (?x365 (ite (= bv16[32] bv2[32]) (concat bv0[2] (extract[31:2] ?x245)) (ite (= bv16[32] bv3[32]) (concat bv0[3] (extract[31:3] ?x245)) ?x357)))
(let (?x371 (ite (= bv16[32] bv0[32]) ?x245 (ite (= bv16[32] bv1[32]) (concat bv0[1] (extract[31:1] ?x245)) ?x365)))
(let (?x372 (concat bv0[32] ?x371))
(let (?x380 (bvsub (bvadd (concat (extract[32:0] ?x372) bv0[31]) (concat (extract[34:0] ?x372) bv0[29])) (concat (extract[36:0] ?x372) bv0[27])))
(let (?x386 (bvsub (bvadd ?x380 (concat (extract[38:0] ?x372) bv0[25])) (concat (extract[40:0] ?x372) bv0[23])))
(let (?x392 (bvsub (bvadd ?x386 (concat (extract[42:0] ?x372) bv0[21])) (concat (extract[44:0] ?x372) bv0[19])))
(let (?x398 (bvsub (bvadd ?x392 (concat (extract[46:0] ?x372) bv0[17])) (concat (extract[48:0] ?x372) bv0[15])))
(let (?x404 (bvsub (bvadd ?x398 (concat (extract[50:0] ?x372) bv0[13])) (concat (extract[52:0] ?x372) bv0[11])))
(let (?x410 (bvsub (bvadd ?x404 (concat (extract[54:0] ?x372) bv0[9])) (concat (extract[56:0] ?x372) bv0[7])))
(let (?x416 (bvsub (bvadd ?x410 (concat (extract[58:0] ?x372) bv0[5])) (concat (extract[60:0] ?x372) bv0[3])))
(let (?x420 (extract[63:32] (bvadd ?x416 (concat (extract[62:0] ?x372) bv0[1]))))
(let (?x427 (ite $x79 (concat bv0[30] (extract[31:30] (bvsub ?x371 ?x420))) (ite (= bv1[32] bv31[32]) (concat bv0[31] (extract[31:31] (bvsub ?x371 ?x420))) bv0[32])))
(let (?x433 (ite $x90 (concat bv0[28] (extract[31:28] (bvsub ?x371 ?x420))) (ite $x85 (concat bv0[29] (extract[31:29] (bvsub ?x371 ?x420))) ?x427)))
(let (?x439 (ite $x102 (concat bv0[26] (extract[31:26] (bvsub ?x371 ?x420))) (ite $x96 (concat bv0[27] (extract[31:27] (bvsub ?x371 ?x420))) ?x433)))
(let (?x445 (ite $x114 (concat bv0[24] (extract[31:24] (bvsub ?x371 ?x420))) (ite $x108 (concat bv0[25] (extract[31:25] (bvsub ?x371 ?x420))) ?x439)))
(let (?x451 (ite $x125 (concat bv0[22] (extract[31:22] (bvsub ?x371 ?x420))) (ite $x119 (concat bv0[23] (extract[31:23] (bvsub ?x371 ?x420))) ?x445)))
(let (?x457 (ite $x137 (concat bv0[20] (extract[31:20] (bvsub ?x371 ?x420))) (ite $x131 (concat bv0[21] (extract[31:21] (bvsub ?x371 ?x420))) ?x451)))
(let (?x463 (ite $x147 (concat bv0[18] (extract[31:18] (bvsub ?x371 ?x420))) (ite $x142 (concat bv0[19] (extract[31:19] (bvsub ?x371 ?x420))) ?x457)))
(let (?x469 (ite $x157 (concat bv0[16] (extract[31:16] (bvsub ?x371 ?x420))) (ite $x153 (concat bv0[17] (extract[31:17] (bvsub ?x371 ?x420))) ?x463)))
(let (?x475 (ite $x168 (concat bv0[14] (extract[31:14] (bvsub ?x371 ?x420))) (ite $x163 (concat bv0[15] (extract[31:15] (bvsub ?x371 ?x420))) ?x469)))
(let (?x481 (ite $x179 (concat bv0[12] (extract[31:12] (bvsub ?x371 ?x420))) (ite $x173 (concat bv0[13] (extract[31:13] (bvsub ?x371 ?x420))) ?x475)))
(let (?x487 (ite $x190 (concat bv0[10] (extract[31:10] (bvsub ?x371 ?x420))) (ite $x184 (concat bv0[11] (extract[31:11] (bvsub ?x371 ?x420))) ?x481)))
(let (?x493 (ite $x202 (concat bv0[8] (extract[31:8] (bvsub ?x371 ?x420))) (ite $x196 (concat bv0[9] (extract[31:9] (bvsub ?x371 ?x420))) ?x487)))
(let (?x499 (ite $x213 (concat bv0[6] (extract[31:6] (bvsub ?x371 ?x420))) (ite $x207 (concat bv0[7] (extract[31:7] (bvsub ?x371 ?x420))) ?x493)))
(let (?x505 (ite $x224 (concat bv0[4] (extract[31:4] (bvsub ?x371 ?x420))) (ite $x219 (concat bv0[5] (extract[31:5] (bvsub ?x371 ?x420))) ?x499)))
(let (?x511 (ite $x236 (concat bv0[2] (extract[31:2] (bvsub ?x371 ?x420))) (ite $x230 (concat bv0[3] (extract[31:3] (bvsub ?x371 ?x420))) ?x505)))
(let (?x421 (bvsub ?x371 ?x420))
(let (?x516 (bvadd (ite $x243 ?x421 (ite $x241 (concat bv0[1] (extract[31:1] ?x421)) ?x511)) ?x420))
(let (?x524 (ite (= bv3[32] bv30[32]) (concat bv0[30] (extract[31:30] ?x516)) (ite (= bv3[32] bv31[32]) (concat bv0[31] (extract[31:31] ?x516)) bv0[32])))
(let (?x532 (ite (= bv3[32] bv28[32]) (concat bv0[28] (extract[31:28] ?x516)) (ite (= bv3[32] bv29[32]) (concat bv0[29] (extract[31:29] ?x516)) ?x524)))
(let (?x540 (ite (= bv3[32] bv26[32]) (concat bv0[26] (extract[31:26] ?x516)) (ite (= bv3[32] bv27[32]) (concat bv0[27] (extract[31:27] ?x516)) ?x532)))
(let (?x548 (ite (= bv3[32] bv24[32]) (concat bv0[24] (extract[31:24] ?x516)) (ite (= bv3[32] bv25[32]) (concat bv0[25] (extract[31:25] ?x516)) ?x540)))
(let (?x556 (ite (= bv3[32] bv22[32]) (concat bv0[22] (extract[31:22] ?x516)) (ite (= bv3[32] bv23[32]) (concat bv0[23] (extract[31:23] ?x516)) ?x548)))
(let (?x564 (ite (= bv3[32] bv20[32]) (concat bv0[20] (extract[31:20] ?x516)) (ite (= bv3[32] bv21[32]) (concat bv0[21] (extract[31:21] ?x516)) ?x556)))
(let (?x572 (ite (= bv3[32] bv18[32]) (concat bv0[18] (extract[31:18] ?x516)) (ite (= bv3[32] bv19[32]) (concat bv0[19] (extract[31:19] ?x516)) ?x564)))
(let (?x580 (ite (= bv3[32] bv16[32]) (concat bv0[16] (extract[31:16] ?x516)) (ite (= bv3[32] bv17[32]) (concat bv0[17] (extract[31:17] ?x516)) ?x572)))
(let (?x588 (ite (= bv3[32] bv14[32]) (concat bv0[14] (extract[31:14] ?x516)) (ite (= bv3[32] bv15[32]) (concat bv0[15] (extract[31:15] ?x516)) ?x580)))
(let (?x596 (ite (= bv3[32] bv12[32]) (concat bv0[12] (extract[31:12] ?x516)) (ite (= bv3[32] bv13[32]) (concat bv0[13] (extract[31:13] ?x516)) ?x588)))
(let (?x604 (ite (= bv3[32] bv10[32]) (concat bv0[10] (extract[31:10] ?x516)) (ite (= bv3[32] bv11[32]) (concat bv0[11] (extract[31:11] ?x516)) ?x596)))
(let (?x612 (ite (= bv3[32] bv8[32]) (concat bv0[8] (extract[31:8] ?x516)) (ite (= bv3[32] bv9[32]) (concat bv0[9] (extract[31:9] ?x516)) ?x604)))
(let (?x620 (ite (= bv3[32] bv6[32]) (concat bv0[6] (extract[31:6] ?x516)) (ite (= bv3[32] bv7[32]) (concat bv0[7] (extract[31:7] ?x516)) ?x612)))
(let (?x628 (ite (= bv3[32] bv4[32]) (concat bv0[4] (extract[31:4] ?x516)) (ite (= bv3[32] bv5[32]) (concat bv0[5] (extract[31:5] ?x516)) ?x620)))
(let (?x636 (ite (= bv3[32] bv2[32]) (concat bv0[2] (extract[31:2] ?x516)) (ite (= bv3[32] bv3[32]) (concat bv0[3] (extract[31:3] ?x516)) ?x628)))
(let (?x642 (ite (= bv3[32] bv0[32]) ?x516 (ite (= bv3[32] bv1[32]) (concat bv0[1] (extract[31:1] ?x516)) ?x636)))
(let (?x648 (bvsub ?x371 (bvadd (concat (extract[28:0] ?x642) bv0[3]) (concat (extract[30:0] ?x642) bv0[1]))))
(= bv253[8] (extract[7:0] ?x648))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))
:assumption
(let (?x13 (concat (select arr51 bv58[32]) (concat (select arr51 bv57[32]) (select arr51 bv56[32]))))
(let (?x16 (concat (select arr51 bv59[32]) ?x13))
(not (= bv4294967295[32] ?x16))))
:assumption
(let (?x13 (concat (select arr51 bv58[32]) (concat (select arr51 bv57[32]) (select arr51 bv56[32]))))
(let (?x16 (concat (select arr51 bv59[32]) ?x13))
(bvule bv100000[32] ?x16)))
:assumption
(let (?x13 (concat (select arr51 bv58[32]) (concat (select arr51 bv57[32]) (select arr51 bv56[32]))))
(let (?x16 (concat (select arr51 bv59[32]) ?x13))
(bvule ?x16 bv999999[32])))
:assumption
(let (?x13 (concat (select arr51 bv58[32]) (concat (select arr51 bv57[32]) (select arr51 bv56[32]))))
(let (?x16 (concat (select arr51 bv59[32]) ?x13))
(let (?x17 (sign_extend[32] ?x16))
(bvsle bv0[64] ?x17))))
:formula
true
)

Я пытался явно установить случайные семена, но это (неудивительно)Т помогло:

Z3_set_param_value(z3_config, "ARITH_RANDOM_SEED", "0");
Z3_set_param_value(z3_config, "RANDOM_SEED", "0");

Нормально ли для Z3 отображать такие значительные изменения времени, просто изменяя названия символов?

Кроме того, существует ли какая-либо схема именования массивов, которая сократила бы время решения по всем направлениям?

Спасибо!