mirror of https://gitlab.com/QEF/q-e.git
178 lines
5.7 KiB
Fortran
178 lines
5.7 KiB
Fortran
double precision function dpmpar(i)
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integer i
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c **********
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c
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c Function dpmpar
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c
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c This function provides double precision machine parameters
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c when the appropriate set of data statements is activated (by
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c removing the c from column 1) and all other data statements are
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c rendered inactive. Most of the parameter values were obtained
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c from the corresponding Bell Laboratories Port Library function.
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c
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c The function statement is
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c
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c double precision function dpmpar(i)
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c
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c where
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c
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c i is an integer input variable set to 1, 2, or 3 which
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c selects the desired machine parameter. If the machine has
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c t base b digits and its smallest and largest exponents are
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c emin and emax, respectively, then these parameters are
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c
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c dpmpar(1) = b**(1 - t), the machine precision,
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c
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c dpmpar(2) = b**(emin - 1), the smallest magnitude,
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c
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c dpmpar(3) = b**emax*(1 - b**(-t)), the largest magnitude.
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c
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c Argonne National Laboratory. MINPACK Project. November 1996.
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c Burton S. Garbow, Kenneth E. Hillstrom, Jorge J. More'
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c
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c **********
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integer mcheps(4)
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integer minmag(4)
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integer maxmag(4)
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double precision dmach(3)
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equivalence (dmach(1),mcheps(1))
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equivalence (dmach(2),minmag(1))
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equivalence (dmach(3),maxmag(1))
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c
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c Machine constants for the IBM 360/370 series,
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c the Amdahl 470/V6, the ICL 2900, the Itel AS/6,
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c the Xerox Sigma 5/7/9 and the Sel systems 85/86.
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c
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c data mcheps(1),mcheps(2) / z34100000, z00000000 /
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c data minmag(1),minmag(2) / z00100000, z00000000 /
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c data maxmag(1),maxmag(2) / z7fffffff, zffffffff /
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c
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c Machine constants for the Honeywell 600/6000 series.
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c
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c data mcheps(1),mcheps(2) / o606400000000, o000000000000 /
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c data minmag(1),minmag(2) / o402400000000, o000000000000 /
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c data maxmag(1),maxmag(2) / o376777777777, o777777777777 /
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c
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c Machine constants for the CDC 6000/7000 series.
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c
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c data mcheps(1) / 15614000000000000000b /
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c data mcheps(2) / 15010000000000000000b /
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c
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c data minmag(1) / 00604000000000000000b /
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c data minmag(2) / 00000000000000000000b /
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c
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c data maxmag(1) / 37767777777777777777b /
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c data maxmag(2) / 37167777777777777777b /
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c
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c Machine constants for the PDP-10 (KA processor).
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c
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c data mcheps(1),mcheps(2) / "114400000000, "000000000000 /
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c data minmag(1),minmag(2) / "033400000000, "000000000000 /
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c data maxmag(1),maxmag(2) / "377777777777, "344777777777 /
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c
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c Machine constants for the PDP-10 (KI processor).
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c
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c data mcheps(1),mcheps(2) / "104400000000, "000000000000 /
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c data minmag(1),minmag(2) / "000400000000, "000000000000 /
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c data maxmag(1),maxmag(2) / "377777777777, "377777777777 /
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c
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c Machine constants for the PDP-11.
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c
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c data mcheps(1),mcheps(2) / 9472, 0 /
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c data mcheps(3),mcheps(4) / 0, 0 /
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c
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c data minmag(1),minmag(2) / 128, 0 /
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c data minmag(3),minmag(4) / 0, 0 /
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c
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c data maxmag(1),maxmag(2) / 32767, -1 /
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c data maxmag(3),maxmag(4) / -1, -1 /
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c
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c Machine constants for the Burroughs 6700/7700 systems.
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c
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c data mcheps(1) / o1451000000000000 /
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c data mcheps(2) / o0000000000000000 /
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c
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c data minmag(1) / o1771000000000000 /
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c data minmag(2) / o7770000000000000 /
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c
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c data maxmag(1) / o0777777777777777 /
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c data maxmag(2) / o7777777777777777 /
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c
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c Machine constants for the Burroughs 5700 system.
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c
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c data mcheps(1) / o1451000000000000 /
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c data mcheps(2) / o0000000000000000 /
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c
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c data minmag(1) / o1771000000000000 /
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c data minmag(2) / o0000000000000000 /
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c
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c data maxmag(1) / o0777777777777777 /
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c data maxmag(2) / o0007777777777777 /
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c
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c Machine constants for the Burroughs 1700 system.
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c
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c data mcheps(1) / zcc6800000 /
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c data mcheps(2) / z000000000 /
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c
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c data minmag(1) / zc00800000 /
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c data minmag(2) / z000000000 /
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c
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c data maxmag(1) / zdffffffff /
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c data maxmag(2) / zfffffffff /
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c
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c Machine constants for the Univac 1100 series.
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c
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c data mcheps(1),mcheps(2) / o170640000000, o000000000000 /
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c data minmag(1),minmag(2) / o000040000000, o000000000000 /
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c data maxmag(1),maxmag(2) / o377777777777, o777777777777 /
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c
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c Machine constants for the Data General Eclipse S/200.
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c
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c Note - it may be appropriate to include the following card -
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c static dmach(3)
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c
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c data minmag/20k,3*0/,maxmag/77777k,3*177777k/
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c data mcheps/32020k,3*0/
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c
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c Machine constants for the Harris 220.
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c
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c data mcheps(1),mcheps(2) / '20000000, '00000334 /
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c data minmag(1),minmag(2) / '20000000, '00000201 /
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c data maxmag(1),maxmag(2) / '37777777, '37777577 /
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c
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c Machine constants for the Cray-1.
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c
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c data mcheps(1) / 0376424000000000000000b /
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c data mcheps(2) / 0000000000000000000000b /
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c
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c data minmag(1) / 0200034000000000000000b /
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c data minmag(2) / 0000000000000000000000b /
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c
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c data maxmag(1) / 0577777777777777777777b /
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c data maxmag(2) / 0000007777777777777776b /
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c
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c Machine constants for the Prime 400.
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c
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c data mcheps(1),mcheps(2) / :10000000000, :00000000123 /
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c data minmag(1),minmag(2) / :10000000000, :00000100000 /
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c data maxmag(1),maxmag(2) / :17777777777, :37777677776 /
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c
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c Machine constants for the VAX-11.
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c
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c data mcheps(1),mcheps(2) / 9472, 0 /
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c data minmag(1),minmag(2) / 128, 0 /
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c data maxmag(1),maxmag(2) / -32769, -1 /
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c
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c Machine constants for IEEE machines.
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c
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data dmach(1) /2.22044604926d-16/
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data dmach(2) /2.22507385852d-308/
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data dmach(3) /1.79769313485d+308/
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c
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dpmpar = dmach(i)
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return
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c
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c Last card of function dpmpar.
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c
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end
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