PSLAMCH(3) ScaLAPACK routine of NEC Numeric Library Collection PSLAMCH(3) NAME PSLAMCH - determine single precision machine parameters SYNOPSIS REAL FUNCTION PSLAMCH( ICTXT, CMACH ) CHARACTER CMACH INTEGER ICTXT PURPOSE PSLAMCH determines single precision machine parameters. ARGUMENTS ICTXT (global input) INTEGER The BLACS context handle in which the computation takes place. CMACH (global input) CHARACTER*1 Specifies the value to be returned by PSLAMCH: = 'E' or 'e', PSLAMCH := eps = 'S' or 's , PSLAMCH := sfmin = 'B' or 'b', PSLAMCH := base = 'P' or 'p', PSLAMCH := eps*base = 'N' or 'n', PSLAMCH := t = 'R' or 'r', PSLAMCH := rnd = 'M' or 'm', PSLAMCH := emin = 'U' or 'u', PSLAMCH := rmin = 'L' or 'l', PSLAMCH := emax = 'O' or 'o', PSLAMCH := 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 addi- tion, 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) ScaLAPACK routine 31 October 2017 PSLAMCH(3)