Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
p?lamch
Determines machine parameters for floating-point arithmetic.
Syntax
valpslamch ( ictxt , cmach )
valpdlamch ( ictxt , cmach )
Include Files
mkl_scalapack.h
Description
pslamch pdlamch The p?lamch routine function determines single precision machine parameters.
Input Parameters
ictxt
(global). INTEGER . The BLACS context handle in which the computation takes place.
cmach
(global) CHARACTER*1 .
Specifies the value to be returned by p?lamch : = ‘E’ or ‘e’ , p?lamch := eps = ‘S’ or ‘s’ , p?lamch := sfmin = ‘B’ or ‘b’ , p?lamch := base = ‘P’ or ‘p’ , p?lamch := eps*base = ‘N’ or ‘n’ , p?lamch := t = ‘R’ or ‘r’ , p?lamch := rnd = ‘M’ or ‘m’ , p?lamch := emin = ‘U’ or ‘u’ , p?lamch := rmin = ‘L’ or ‘l’ , p?lamch := emax = ‘O’ or ‘o’ , p?lamch := rmax , where eps = relative machine precision sfmin = safe minimum, such that 1/sfmin does not overflow base = base of the machine prec = eps*base t = number of (base) digits in the mantissa rnd = 1.0 when rounding occurs in addition, 0.0 otherwise emin = minimum exponent before (gradual) underflow rmin = underflow threshold - base ( emin -1) emax = largest exponent before overflow rmax = overflow threshold - (base^{emax})*(1-eps)