The Computer Language
24.11 Benchmarks Game

pidigits Go #8 program

source code

/* The Computer Language Benchmarks Game
 * https://salsa.debian.org/benchmarksgame-team/benchmarksgame/
 *
 * based on pidigits.c (by Paolo Bonzini & Sean Bartlett,
 *                      modified by Michael Mellor)
 *
 * contributed by The Go Authors.
 * line printer hack by Sean Lake
 * modified by Bert Gijsbers
 * make pidigits.go #2 use "math/big"
 */

package main

import (
    "bufio"
    "flag"
    "fmt"
    "math/big"
    "os"
    "runtime"
    "strconv"
)

var n = 0
var silent = false

var (
    tmp1  = big.NewInt(0)
    tmp2  = big.NewInt(0)
    y2    = big.NewInt(1)
    bigk  = big.NewInt(0)
    accum = big.NewInt(0)
    denom = big.NewInt(1)
    numer = big.NewInt(1)
    ten   = big.NewInt(10)
    three = big.NewInt(3)
    four  = big.NewInt(4)
)

func next_term(k int64) int64 {
    for {
        k++
        y2.SetInt64(k*2 + 1)
        bigk.SetInt64(k)

        tmp1.Lsh(numer, 1)
        accum.Add(accum, tmp1)
        accum.Mul(accum, y2)
        denom.Mul(denom, y2)
        numer.Mul(numer, bigk)

        if accum.Cmp(numer) > 0 {
            return k
        }
    }
}

func extract_digit(nth *big.Int) int64 {
    tmp1.Mul(nth, numer)
    tmp2.Add(tmp1, accum)
    tmp1.Div(tmp2, denom)
    return tmp1.Int64()
}

func next_digit(k int64) (int64, int64) {
    for {
        k = next_term(k)
        d3 := extract_digit(three)
        d4 := extract_digit(four)
        if d3 == d4 {
            return d3, k
        }
    }
}

func eliminate_digit(d int64) {
    tmp1.SetInt64(d)
    accum.Sub(accum, tmp1.Mul(denom, tmp1))
    accum.Mul(accum, ten)
    numer.Mul(numer, ten)
}

func init() {
    runtime.GOMAXPROCS(1)
    flag.Parse()
    if flag.NArg() > 0 {
        n, _ = strconv.Atoi(flag.Arg(0))
    }
}

func main() {
    w := bufio.NewWriter(os.Stdout)
    defer w.Flush()
    line := make([]byte, 0, 10)
    var d, k int64
    for i := 1; i <= n; i++ {
        d, k = next_digit(k)
        line = append(line, byte(d)+'0')
        if len(line) == 10 {
            if silent != true {
                fmt.Fprintf(w, "%s\t:%d\n", string(line), i)
            }
            line = line[:0]
        }
        eliminate_digit(d)
    }
    if len(line) > 0 && silent != true {
        fmt.Fprintf(w, "%-10s\t:%d\n", string(line), n)
    }
}
    

notes, command-line, and program output

NOTES:
64-bit Ubuntu quad core
go version go1.23.1 linux/amd64
GOAMD64=v2


 Fri, 06 Sep 2024 00:18:44 GMT

MAKE:
/opt/src/go1.23.1/go/bin/go build -o pidigits.go-8.go_run pidigits.go-8.go

7.24s to complete and log all make actions

COMMAND LINE:
 ./pidigits.go-8.go_run 10000

(TRUNCATED) PROGRAM OUTPUT:
3141592653	:10
5897932384	:20
6264338327	:30
9502884197	:40
1693993751	:50
0582097494	:60
4592307816	:70
4062862089	:80
9862803482	:90
5342117067	:100
9821480865	:110
1328230664	:120
7093844609	:130
5505822317	:140
2535940812	:150
8481117450	:160
2841027019	:170
3852110555	:180
9644622948	:190
9549303819	:200
6442881097	:210
5665933446	:220
1284756482	:230
3378678316	:240
5271201909	:250
1456485669	:260
2346034861	:270
0454326648	:280
2133936072	:290
6024914127	:300
3724587006	:310
6063155881	:320
7488152092	:330
0962829254	:340
0917153643	:350
6789259036	:360
0011330530	:370
5488204665	:380
2138414695	:390
1941511609	:400
4330572703	:410
6575959195	:420
3092186117	:430
3819326117	:440
9310511854	:450
8074462379	:460
9627495673	:470
5188575272	:480
4891227938	:490
1830119491	:500
2983367336	:510
2440656643	:520
0860213949	:530
4639522473	:540
7190702179	:550
8609437027	:560
7053921717	:570
6293176752	:580
3846748184	:590
6766940513	:600
2000568127	:610
1452635608	:620
2778577134	:630
2757789609	:640
1736371787	:650
2146844090	:660
1224953430	:670
1465495853	:680
7105079227	:690
9689258923	:700
5420199561	:710
1212902196	:720
0864034418	:730
1598136297	:740
7477130996	:750
0518707211	:760
3499999983	:770
7297804995	:780
1059731732	:790
8160963185	:800
9502445945	:810
5346908302	:820
6425223082	:830
5334468503	:840
5261931188	:850
1710100031	:860
3783875288	:870
6587533208	:880
3814206171	:890
7766914730	:900
3598253490	:910
4287554687	:920
3115956286	:930
3882353787	:940
5937519577	:950
8185778053	:960
2171226806	:970
6130019278	:980
7661119590	:990
9216420198	:1000
9380952572	:1010
0106548586	:1020
3278865936	:1030
1533818279	:1040
6823030195	:1050
2035301852	:1060
9689957736	:1070
2259941389	:1080
1249721775	:1090
2834791315	:1100
1557485724	:1110
2454150695	:1120
9508295331	:1130
1686172785	:1140
5889075098	:1150
3817546374	:1160
6493931925	:1170
5060400927	:1180
7016711390	:1190
0984882401	:1200
2858361603	:1210
5637076601	:1220
0471018194	:1230
2955596198	:1240
9467678374	:1250
4944825537	:1260
9774726847	:1270
1040475346	:1280
4620804668	:1290
4259069491	:1300
2933136770	:1310
2898915210	:1320
4752162056	:1330
9660240580	:1340
3815019351	:1350
1253382430	:1360
0355876402	:1370
4749647326	:1380
3914199272	:1390
6042699227	:1400
9678235478	:1410
1636009341	:1420
7216412199	:1430
2458631503	:1440
0286182974	:1450
5557067498	:1460
3850549458	:1470
8586926995	:1480
6909272107	:1490
9750930295	:1500
5321165344	:1510
9872027559	:1520
6023648066	:1530
5499119881	:1540
8347977535	:1550
6636980742	:1560
6542527862	:1570
5518184175	:1580
7467289097	:1590
7772793800	:1600
0816470600	:1610
1614524919	:1620
2173217214	:1630
7723501414	:1640
4197356854	:1650
8161361157	:1660
3525521334	:1670
7574184946	:1680
8438523323	:1690
9073941433	:1700
3454776241	:1710
6862518983	:1720
5694855620	:1730
9921922218	:1740
4272550254	:1750
2568876717	:1760
9049460165	:1770
3466804988	:1780
6272327917	:1790
8608578438	:1800
3827967976	:1810
6814541009	:1820
5388378636	:1830
0950680064	:1840
2251252051	:1850
1739298489	:1860
6084128488	:1870
6269456042	:1880
4196528502	:1890
2210661186	:1900
3067442786	:1910
2203919494	:1920
5047123713	:1930
7869609563	:1940
6437191728	:1950
7467764657	:1960
5739624138	:1970
9086583264	:1980
5995813390	:1990
4780275900	:2000
9946576407	:2010
8951269468	:2020
3983525957	:2030
0982582262	:2040
0522489407	:2050
7267194782	:2060
6848260147	:2070
6990902640	:2080
1363944374	:2090
5530506820	:2100
3496252451	:2110
7493996514	:2120
3142980919	:2130
0659250937	:2140
2216964615	:2150
1570985838	:2160
7410597885	:2170
9597729754	:2180
9893016175	:2190
3928468138	:2200
2686838689	:2210
4277415599	:2220
1855925245	:2230
9539594310	:2240
4997252468	:2250
0845987273	:2260
6446958486	:2270
5383673622	:2280
2626099124	:2290
6080512438	:2300
8439045124	:2310
4136549762	:2320
7807977156	:2330
9143599770	:2340
0129616089	:2350
4416948685	:2360
5584840635	:2370
3422072225	:2380
8284886481	:2390
5845602850	:2400
6016842739	:2410
4522674676	:2420
7889525213	:2430
8522549954	:2440
6667278239	:2450
8645659611	:2460
6354886230	:2470
5774564980	:2480
3559363456	:2490
8174324112	:2500
5150760694	:2510
7945109659	:2520
6094025228	:2530
8797108931	:2540
4566913686	:2550
7228748940	:2560
5601015033	:2570
0861792868	:2580
0920874760	:2590
9178249385	:2600
8900971490	:2610
9675985261	:2620
3655497818	:2630
9312978482	:2640
1682998948	:2650
7226588048	:2660
5756401427	:2670
0477555132	:2680
3796414515	:2690
2374623436	:2700
4542858444	:2710
7952658678	:2720
2105114135	:2730
4735739523	:2740
1134271661	:2750
0213596953	:2760
6231442952	:2770
4849371871	:2780
1014576540	:2790
3590279934	:2800
4037420073	:2810
1057853906	:2820
2198387447	:2830
8084784896	:2840
8332144571	:2850
3868751943	:2860
5064302184	:2870
5319104848	:2880
1005370614	:2890
6806749192	:2900
7819119793	:2910
9952061419	:2920
6634287544	:2930
4064374512	:2940
3718192179	:2950
9983910159	:2960
1956181467	:2970
5142691239	:2980
7489409071	:2990
8649423196	:3000
1567945208	:3010
0951465502	:3020
2523160388	:3030
1930142093	:3040
7621378559	:3050
5663893778	:3060
7083039069	:3070
7920773467	:3080
2218256259	:3090
9661501421	:3100
5030680384	:3110
4773454920	:3120
2605414665	:3130
9252014974	:3140
4285073251	:3150
8666002132	:3160
4340881907	:3170
1048633173	:3180
4649651453	:3190
9057962685	:3200
6100550810	:3210
6658796998	:3220
1635747363	:3230
8405257145	:3240
9102897064	:3250
1401109712	:3260
0628043903	:3270
9759515677	:3280
1577004203	:3290
3786993600	:3300
7230558763	:3310
1763594218	:3320
7312514712	:3330
0532928191	:3340
8261861258	:3350
6732157919	:3360
8414848829	:3370
1644706095	:3380
7527069572	:3390
2091756711	:3400
6722910981	:3410
6909152801	:3420
7350671274	:3430
8583222871	:3440
8352093539	:3450
6572512108	:3460
3579151369	:3470
8820914442	:3480
1006751033	:3490
4671103141	:3500
2671113699	:3510
0865851639	:3520
8315019701	:3530
6515116851	:3540
7143765761	:3550
8351556508	:3560
8490998985	:3570
9982387345	:3580
5283316355	:3590
0764791853	:3600
5893226185	:3610
4896321329	:3620
3308985706	:3630
4204675259	:3640
0709154814	:3650
1654985946	:3660
1637180270	:3670
9819943099	:3680
2448895757	:3690
1282890592	:3700
3233260972	:3710
9971208443	:3720
3573265489	:3730
3823911932	:3740
5974636673	:3750
0583604142	:3760
8138830320	:3770
3824903758	:3780
9852437441	:3790
7029132765	:3800
6180937734	:3810
4403070746	:3820
9211201913	:3830
0203303801	:3840
9762110110	:3850
0449293215	:3860
1608424448	:3870
5963766983	:3880
8952286847	:3890
8312355265	:3900
8213144957	:3910
6857262433	:3920
4418930396	:3930
8642624341	:3940
0773226978	:3950
0280731891	:3960
5441101044	:3970
6823252716	:3980
2010526522	:3990
7211166039	:4000
6665573092	:4010
5471105578	:4020
5376346682	:4030
0653109896	:4040
5269186205	:4050
6476931257	:4060
0586356620	:4070
1855810072	:4080
9360659876	:4090
4861179104	:4100
5334885034	:4110
6113657686	:4120
7532494416	:4130
6803962657	:4140
9787718556	:4150
0845529654	:4160
1266540853	:4170
0614344431	:4180
8586769751	:4190
4566140680	:4200
0700237877	:4210
6591344017	:4220
1274947042	:4230
0562230538	:4240
9945613140	:4250
7112700040	:4260
7854733269	:4270
9390814546	:4280
6464588079	:4290
7270826683	:4300
0634328587	:4310
8569830523	:4320
5808933065	:4330
7574067954	:4340
5716377525	:4350
4202114955	:4360
7615814002	:4370
5012622859	:4380
4130216471	:4390
5509792592	:4400
3099079654	:4410
7376125517	:4420
6567513575	:4430
1782966645	:4440
4779174501	:4450
1299614890	:4460
3046399471	:4470
3296210734	:4480
0437518957	:4490
3596145890	:4500
1938971311	:4510
1790429782	:4520
8564750320	:4530
3198691514	:4540
0287080859	:4550
9048010941	:4560
2147221317	:4570
9476477726	:4580
2241425485	:4590
4540332157	:4600
1853061422	:4610
8813758504	:4620
3063321751	:4630
8297986622	:4640
3717215916	:4650
0771669254	:4660
7487389866	:4670
5494945011	:4680
4654062843	:4690
3663937900	:4700
3976926567	:4710
2146385306	:4720
7360965712	:4730
0918076383	:4740
2716641627	:4750
4888800786	:4760
9256029022	:4770
8472104031	:4780
7211860820	:4790
4190004229	:4800
6617119637	:4810
7921337575	:4820
1149595015	:4830
6604963186	:4840
2947265473	:4850
6425230817	:4860
7036751590	:4870
6735023507	:4880
2835405670	:4890
4038674351	:4900
3622224771	:4910
5891504953	:4920
0984448933	:4930
3096340878	:4940
0769325993	:4950
9780541934	:4960
1447377441	:4970
8426312986	:4980
0809988868	:4990
7413260472	:5000
1569516239	:5010
6586457302	:5020
1631598193	:5030
1951673538	:5040
1297416772	:5050
9478672422	:5060
9246543668	:5070
0098067692	:5080
8238280689	:5090
9640048243	:5100
5403701416	:5110
3149658979	:5120
4092432378	:5130
9690706977	:5140
9422362508	:5150
2216889573	:5160
8379862300	:5170
1593776471	:5180
6512289357	:5190
8601588161	:5200
7557829735	:5210
2334460428	:5220
1512627203	:5230
7343146531	:5240
9777741603	:5250
1990665541	:5260
8763979293	:5270
3441952154	:5280
1341899485	:5290
4447345673	:5300
8316249934	:5310
1913181480	:5320
9277771038	:5330
6387734317	:5340
7207545654	:5350
5322077709	:5360
2120190516	:5370
6096280490	:5380
9263601975	:5390
9882816133	:5400
2316663652	:5410
8619326686	:5420
3360627356	:5430
7630354477	:5440
6280350450	:5450
7772355471	:5460
0585954870	:5470
2790814356	:5480
2401451718	:5490
0624643626	:5500
7945612753	:5510
1813407833	:5520
0336254232	:5530
7839449753	:5540
8243720583	:5550
5311477119	:5560
9260638133	:5570
4677687969	:5580
5970309833	:5590
9130771098	:5600
7040859133	:5610
7464144282	:5620
2772634659	:5630
4704745878	:5640
4778720192	:5650
7715280731	:5660
7679077071	:5670
5721344473	:5680
0605700733	:5690
4924369311	:5700
3835049316	:5710
3128404251	:5720
2192565179	:5730
8069411352	:5740
8013147013	:5750
0478164378	:5760
8518529092	:5770
8545201165	:5780
8393419656	:5790
2134914341	:5800
5956258658	:5810
6557055269	:5820
0496520985	:5830
8033850722	:5840
4264829397	:5850
2858478316	:5860
3057777560	:5870
6888764462	:5880
4824685792	:5890
6039535277	:5900
3480304802	:5910
9005876075	:5920
8251047470	:5930
9164396136	:5940
2676044925	:5950
6274204208	:5960
3208566119	:5970
0625454337	:5980
2131535958	:5990
4506877246	:6000
0290161876	:6010
6795240616	:6020
3425225771	:6030
9542916299	:6040
1930645537	:6050
7991403734	:6060
0432875262	:6070
8889639958	:6080
7947572917	: