Radiance ev program

EV(1)                                                                    EV(1)

NAME

       ev - evaluate expressions

SYNOPSIS

       ev 'expr' ..

DESCRIPTION

       Ev  evaluates  expressions  given  on  the  command line, and sends the
       results to the standard output, one per line.  An  expression  contains
       real numbers, function calls, and the following operators:

            +  -  *  /  ^

       Operators are evaluated left to right, except '^', which is right asso-
       ciative.  Powers have the highest precedence; multiplication and  divi-
       sion are evaluated before addition and subtraction.  Expressions can be
       grouped with parentheses.  All values are double precision real.

       The following library of functions is available:

       if(cond, then, else)
                 if cond is greater than zero, then  is  evaluated,  otherwise
                 else is evaluated.

       select(N, a1, a2, ..)
                 return  aN  (N  is  rounded to the nearest integer).  If N is
                 zero, the number of available arguments is returned.

       rand(x)   compute a random number between 0 and 1 based on x.

       floor(x)  return largest integer not greater than x.

       ceil(x)   return smallest integer not less than x.

       sqrt(x)   return square root of x.

       exp(x)    compute e to the power of x (e approx = 2.718281828).

       log(x)    compute the logarithm of x to the base e.

       log10(x)  compute the logarithm of x to the base 10.

       sin(x), cos(x), tan(x)
                 trigonometric functions.

       asin(x), acos(x), atan(x)
                 inverse trigonometric functions.

       atan2(y, x)
                 inverse tangent of y/x (range -pi to pi).

EXAMPLE

       To pass the square root of two and the sine of .5 to a program:

         program `ev 'sqrt(2)' 'sin(.5)'`

AUTHOR

       Greg Ward

SEE ALSO

       icalc(1), rcalc(1)


RADIANCE                           10/28/96                              EV(1)