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math: add factorial function (via factorial table)

This commit is contained in:
Ulises Jeremias Cornejo Fandos 2019-12-03 05:34:26 -03:00 committed by Alexander Medvednikov
parent 6d28a80bf8
commit b31ec4ca9a
3 changed files with 189 additions and 43 deletions

177
vlib/math/fact_tables.v Normal file
View File

@ -0,0 +1,177 @@
module math
const(
factorials = [
f64(1.000000000000000000000e+0), /* 0! */
1.000000000000000000000e+0, /* 1! */
2.000000000000000000000e+0, /* 2! */
6.000000000000000000000e+0, /* 3! */
2.400000000000000000000e+1, /* 4! */
1.200000000000000000000e+2, /* 5! */
7.200000000000000000000e+2, /* 6! */
5.040000000000000000000e+3, /* 7! */
4.032000000000000000000e+4, /* 8! */
3.628800000000000000000e+5, /* 9! */
3.628800000000000000000e+6, /* 10! */
3.991680000000000000000e+7, /* 11! */
4.790016000000000000000e+8, /* 12! */
6.227020800000000000000e+9, /* 13! */
8.717829120000000000000e+10, /* 14! */
1.307674368000000000000e+12, /* 15! */
2.092278988800000000000e+13, /* 16! */
3.556874280960000000000e+14, /* 17! */
6.402373705728000000000e+15, /* 18! */
1.216451004088320000000e+17, /* 19! */
2.432902008176640000000e+18, /* 20! */
5.109094217170944000000e+19, /* 21! */
1.124000727777607680000e+21, /* 22! */
2.585201673888497664000e+22, /* 23! */
6.204484017332394393600e+23, /* 24! */
1.551121004333098598400e+25, /* 25! */
4.032914611266056355840e+26, /* 26! */
1.088886945041835216077e+28, /* 27! */
3.048883446117138605015e+29, /* 28! */
8.841761993739701954544e+30, /* 29! */
2.652528598121910586363e+32, /* 30! */
8.222838654177922817726e+33, /* 31! */
2.631308369336935301672e+35, /* 32! */
8.683317618811886495518e+36, /* 33! */
2.952327990396041408476e+38, /* 34! */
1.033314796638614492967e+40, /* 35! */
3.719933267899012174680e+41, /* 36! */
1.376375309122634504632e+43, /* 37! */
5.230226174666011117600e+44, /* 38! */
2.039788208119744335864e+46, /* 39! */
8.159152832478977343456e+47, /* 40! */
3.345252661316380710817e+49, /* 41! */
1.405006117752879898543e+51, /* 42! */
6.041526306337383563736e+52, /* 43! */
2.658271574788448768044e+54, /* 44! */
1.196222208654801945620e+56, /* 45! */
5.502622159812088949850e+57, /* 46! */
2.586232415111681806430e+59, /* 47! */
1.241391559253607267086e+61, /* 48! */
6.082818640342675608723e+62, /* 49! */
3.041409320171337804361e+64, /* 50! */
1.551118753287382280224e+66, /* 51! */
8.065817517094387857166e+67, /* 52! */
4.274883284060025564298e+69, /* 53! */
2.308436973392413804721e+71, /* 54! */
1.269640335365827592597e+73, /* 55! */
7.109985878048634518540e+74, /* 56! */
4.052691950487721675568e+76, /* 57! */
2.350561331282878571829e+78, /* 58! */
1.386831185456898357379e+80, /* 59! */
8.320987112741390144276e+81, /* 60! */
5.075802138772247988009e+83, /* 61! */
3.146997326038793752565e+85, /* 62! */
1.982608315404440064116e+87, /* 63! */
1.268869321858841641034e+89, /* 64! */
8.247650592082470666723e+90, /* 65! */
5.443449390774430640037e+92, /* 66! */
3.647111091818868528825e+94, /* 67! */
2.480035542436830599601e+96, /* 68! */
1.711224524281413113725e+98, /* 69! */
1.197857166996989179607e+100, /* 70! */
8.504785885678623175212e+101, /* 71! */
6.123445837688608686152e+103, /* 72! */
4.470115461512684340891e+105, /* 73! */
3.307885441519386412260e+107, /* 74! */
2.480914081139539809195e+109, /* 75! */
1.885494701666050254988e+111, /* 76! */
1.451830920282858696341e+113, /* 77! */
1.132428117820629783146e+115, /* 78! */
8.946182130782975286851e+116, /* 79! */
7.156945704626380229481e+118, /* 80! */
5.797126020747367985880e+120, /* 81! */
4.753643337012841748421e+122, /* 82! */
3.945523969720658651190e+124, /* 83! */
3.314240134565353266999e+126, /* 84! */
2.817104114380550276949e+128, /* 85! */
2.422709538367273238177e+130, /* 86! */
2.107757298379527717214e+132, /* 87! */
1.854826422573984391148e+134, /* 88! */
1.650795516090846108122e+136, /* 89! */
1.485715964481761497310e+138, /* 90! */
1.352001527678402962552e+140, /* 91! */
1.243841405464130725548e+142, /* 92! */
1.156772507081641574759e+144, /* 93! */
1.087366156656743080274e+146, /* 94! */
1.032997848823905926260e+148, /* 95! */
9.916779348709496892096e+149, /* 96! */
9.619275968248211985333e+151, /* 97! */
9.426890448883247745626e+153, /* 98! */
9.332621544394415268170e+155, /* 99! */
9.332621544394415268170e+157, /* 100! */
9.425947759838359420852e+159, /* 101! */
9.614466715035126609269e+161, /* 102! */
9.902900716486180407547e+163, /* 103! */
1.029901674514562762385e+166, /* 104! */
1.081396758240290900504e+168, /* 105! */
1.146280563734708354534e+170, /* 106! */
1.226520203196137939352e+172, /* 107! */
1.324641819451828974500e+174, /* 108! */
1.443859583202493582205e+176, /* 109! */
1.588245541522742940425e+178, /* 110! */
1.762952551090244663872e+180, /* 111! */
1.974506857221074023537e+182, /* 112! */
2.231192748659813646597e+184, /* 113! */
2.543559733472187557120e+186, /* 114! */
2.925093693493015690688e+188, /* 115! */
3.393108684451898201198e+190, /* 116! */
3.969937160808720895402e+192, /* 117! */
4.684525849754290656574e+194, /* 118! */
5.574585761207605881323e+196, /* 119! */
6.689502913449127057588e+198, /* 120! */
8.094298525273443739682e+200, /* 121! */
9.875044200833601362412e+202, /* 122! */
1.214630436702532967577e+205, /* 123! */
1.506141741511140879795e+207, /* 124! */
1.882677176888926099744e+209, /* 125! */
2.372173242880046885677e+211, /* 126! */
3.012660018457659544810e+213, /* 127! */
3.856204823625804217357e+215, /* 128! */
4.974504222477287440390e+217, /* 129! */
6.466855489220473672507e+219, /* 130! */
8.471580690878820510985e+221, /* 131! */
1.118248651196004307450e+224, /* 132! */
1.487270706090685728908e+226, /* 133! */
1.992942746161518876737e+228, /* 134! */
2.690472707318050483595e+230, /* 135! */
3.659042881952548657690e+232, /* 136! */
5.012888748274991661035e+234, /* 137! */
6.917786472619488492228e+236, /* 138! */
9.615723196941089004197e+238, /* 139! */
1.346201247571752460588e+241, /* 140! */
1.898143759076170969429e+243, /* 141! */
2.695364137888162776589e+245, /* 142! */
3.854370717180072770522e+247, /* 143! */
5.550293832739304789551e+249, /* 144! */
8.047926057471991944849e+251, /* 145! */
1.174997204390910823948e+254, /* 146! */
1.727245890454638911203e+256, /* 147! */
2.556323917872865588581e+258, /* 148! */
3.808922637630569726986e+260, /* 149! */
5.713383956445854590479e+262, /* 150! */
8.627209774233240431623e+264, /* 151! */
1.311335885683452545607e+267, /* 152! */
2.006343905095682394778e+269, /* 153! */
3.089769613847350887959e+271, /* 154! */
4.789142901463393876336e+273, /* 155! */
7.471062926282894447084e+275, /* 156! */
1.172956879426414428192e+278, /* 157! */
1.853271869493734796544e+280, /* 158! */
2.946702272495038326504e+282, /* 159! */
4.714723635992061322407e+284, /* 160! */
7.590705053947218729075e+286, /* 161! */
1.229694218739449434110e+289, /* 162! */
2.004401576545302577600e+291, /* 163! */
3.287218585534296227263e+293, /* 164! */
5.423910666131588774984e+295, /* 165! */
9.003691705778437366474e+297, /* 166! */
1.503616514864999040201e+300, /* 167! */
2.526075744973198387538e+302, /* 168! */
4.269068009004705274939e+304, /* 169! */
7.257415615307998967397e+306 /* 170! */
]
)

View File

@ -133,49 +133,20 @@ pub fn exp2(a f64) f64 {
}
// factorial calculates the factorial of the provided value.
// TODO bring back once multiple value functions are implemented
/*
fn recursive_product( n int, current_number_ptr &int) int{
mut m := n / 2
if (m == 0){
return *current_number_ptr += 2
}
if (n == 2){
return (*current_number_ptr += 2) * (*current_number_ptr += 2)
}
return recursive_product((n - m), *current_number_ptr) * recursive_product(m, *current_number_ptr)
}
pub fn factorial(n f64) f64 {
// For a large postive argument (n >= factorials.len) return max_f64
pub fn factorial(n int) i64 {
if n < 0 {
panic('factorial: Cannot find factorial of negative number')
}
if n < 2 {
return i64(1)
}
mut r := 1
mut p := 1
mut current_number := 1
mut h := 0
mut shift := 0
mut high := 1
mut len := high
mut log2n := int(floor(log2(n)))
for ;h != n; {
shift += h
h = n >> log2n
log2n -= 1
len = high
high = (h - 1) | 1
len = (high - len)/2
if (len > 0){
p *= recursive_product(len, &current_number)
r *= p
}
}
return i64((r << shift))
if n >= factorials.len {
return max_f64
}
/* Otherwise return n!. */
if n == f64(i64(n)) && n >= 0.0 {
return f64(factorials[i64(n)])
}
return gamma(n + 1.0)
}
*/
// floor returns the nearest f64 lower or equal of the provided value.
pub fn floor(a f64) f64 {

View File

@ -27,13 +27,11 @@ fn test_digits() {
assert negative_digits[2] == -1
}
/*
fn test_factorial() {
assert math.factorial(12) == 479001600
assert math.factorial(5) == 120
assert math.factorial(0) == 1
}
*/
fn test_erf() {
assert math.erf(0) == 0