#include "f2c.h" /* Subroutine */ int slaruv_slu(integer *iseed, integer *n, real *x) { /* -- LAPACK auxiliary routine (version 2.0) -- Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd., Courant Institute, Argonne National Lab, and Rice University October 31, 1992 Purpose ======= SLARUV returns a vector of n random real numbers from a uniform (0,1) distribution (n <= 128). This is an auxiliary routine called by SLARNV and CLARNV. Arguments ========= ISEED (input/output) INTEGER array, dimension (4) On entry, the seed of the random number generator; the array elements must be between 0 and 4095, and ISEED(4) must be odd. On exit, the seed is updated. N (input) INTEGER The number of random numbers to be generated. N <= 128. X (output) REAL array, dimension (N) The generated random numbers. Further Details =============== This routine uses a multiplicative congruential method with modulus 2**48 and multiplier 33952834046453 (see G.S.Fishman, 'Multiplicative congruential random number generators with modulus 2**b: an exhaustive analysis for b = 32 and a partial analysis for b = 48', Math. Comp. 189, pp 331-344, 1990). 48-bit integers are stored in 4 integer array elements with 12 bits per element. Hence the routine is portable across machines with integers of 32 bits or more. ===================================================================== Parameter adjustments Function Body */ /* Initialized data */ static integer mm[512] /* was [128][4] */ = { 494,2637,255,2008,1253, 3344,4084,1739,3143,3468,688,1657,1238,3166,1292,3422,1270,2016, 154,2862,697,1706,491,931,1444,444,3577,3944,2184,1661,3482,657, 3023,3618,1267,1828,164,3798,3087,2400,2870,3876,1905,1593,1797, 1234,3460,328,2861,1950,617,2070,3331,769,1558,2412,2800,189,287, 2045,1227,2838,209,2770,3654,3993,192,2253,3491,2889,2857,2094, 1818,688,1407,634,3231,815,3524,1914,516,164,303,2144,3480,119, 3357,837,2826,2332,2089,3780,1700,3712,150,2000,3375,1621,3090, 3765,1149,3146,33,3082,2741,359,3316,1749,185,2784,2202,2199,1364, 1244,2020,3160,2785,2772,1217,1822,1245,2252,3904,2774,997,2573, 1148,545,322,789,1440,752,2859,123,1848,643,2405,2638,2344,46, 3814,913,3649,339,3808,822,2832,3078,3633,2970,637,2249,2081,4019, 1478,242,481,2075,4058,622,3376,812,234,641,4005,1122,3135,2640, 2302,40,1832,2247,2034,2637,1287,1691,496,1597,2394,2584,1843,336, 1472,2407,433,2096,1761,2810,566,442,41,1238,1086,603,840,3168, 1499,1084,3438,2408,1589,2391,288,26,512,1456,171,1677,2657,2270, 2587,2961,1970,1817,676,1410,3723,2803,3185,184,663,499,3784,1631, 1925,3912,1398,1349,1441,2224,2411,1907,3192,2786,382,37,759,2948, 1862,3802,2423,2051,2295,1332,1832,2405,3638,3661,327,3660,716, 1842,3987,1368,1848,2366,2508,3754,1766,3572,2893,307,1297,3966, 758,2598,3406,2922,1038,2934,2091,2451,1580,1958,2055,1507,1078, 3273,17,854,2916,3971,2889,3831,2621,1541,893,736,3992,787,2125, 2364,2460,257,1574,3912,1216,3248,3401,2124,2762,149,2245,166,466, 4018,1399,190,2879,153,2320,18,712,2159,2318,2091,3443,1510,449, 1956,2201,3137,3399,1321,2271,3667,2703,629,2365,2431,1113,3922, 2554,184,2099,3228,4012,1921,3452,3901,572,3309,3171,817,3039, 1696,1256,3715,2077,3019,1497,1101,717,51,981,1978,1813,3881,76, 3846,3694,1682,124,1660,3997,479,1141,886,3514,1301,3604,1888, 1836,1990,2058,692,1194,20,3285,2046,2107,3508,3525,3801,2549, 1145,2253,305,3301,1065,3133,2913,3285,1241,1197,3729,2501,1673, 541,2753,949,2361,1165,4081,2725,3305,3069,3617,3733,409,2157, 1361,3973,1865,2525,1409,3445,3577,77,3761,2149,1449,3005,225,85, 3673,3117,3089,1349,2057,413,65,1845,697,3085,3441,1573,3689,2941, 929,533,2841,4077,721,2821,2249,2397,2817,245,1913,1997,3121,997, 1833,2877,1633,981,2009,941,2449,197,2441,285,1473,2741,3129,909, 2801,421,4073,2813,2337,1429,1177,1901,81,1669,2633,2269,129,1141, 249,3917,2481,3941,2217,2749,3041,1877,345,2861,1809,3141,2825, 157,2881,3637,1465,2829,2161,3365,361,2685,3745,2325,3609,3821, 3537,517,3017,2141,1537 }; /* System generated locals */ integer i__1; /* Local variables */ static integer i, i1, i2, i3, i4, it1, it2, it3, it4; #define MM(I) mm[(I)] #define WAS(I) was[(I)] #define ISEED(I) iseed[(I)-1] #define X(I) x[(I)-1] i1 = ISEED(1); i2 = ISEED(2); i3 = ISEED(3); i4 = ISEED(4); i__1 = min(*n,128); for (i = 1; i <= min(*n,128); ++i) { /* Multiply the seed by i-th power of the multiplier modulo 2** 48 */ it4 = i4 * MM(i + 383); it3 = it4 / 4096; it4 -= it3 << 12; it3 = it3 + i3 * MM(i + 383) + i4 * MM(i + 255); it2 = it3 / 4096; it3 -= it2 << 12; it2 = it2 + i2 * MM(i + 383) + i3 * MM(i + 255) + i4 * MM(i + 127); it1 = it2 / 4096; it2 -= it1 << 12; it1 = it1 + i1 * MM(i + 383) + i2 * MM(i + 255) + i3 * MM(i + 127) + i4 * MM(i - 1); it1 %= 4096; /* Convert 48-bit integer to a real number in the interval (0,1 ) */ X(i) = ((real) it1 + ((real) it2 + ((real) it3 + (real) it4 * 2.44140625e-4f) * 2.44140625e-4f) * 2.44140625e-4f) * 2.44140625e-4f; /* L10: */ } /* Return final value of seed */ ISEED(1) = it1; ISEED(2) = it2; ISEED(3) = it3; ISEED(4) = it4; return 0; /* End of SLARUV */ } /* slaruv_slu */