Developer Reference for Intel® oneAPI Math Kernel Library for C
p?lamch
Determines machine parameters for floating-point arithmetic.
Syntax
floatpslamch ( MKL_INT*ictxt , char*cmach );
doublepdlamch ( MKL_INT*ictxt , char*cmach );
Include Files
mkl_scalapack.h
Description
pslamch pdlamch The p?lamch routine function determines single precision machine parameters.
Input Parameters
ictxt
(global). The BLACS context handle in which the computation takes place.
cmach
(global)
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)