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.\" RCSid "$Id: ev.1,v 1.3 2004/01/01 19:31:44 greg Exp $" |
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.TH EV 1 10/28/96 RADIANCE |
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.SH NAME |
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ev - evaluate expressions |
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.SH SYNOPSIS |
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.B ev 'expr' .. |
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.SH DESCRIPTION |
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.I Ev |
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evaluates expressions given on the command line, and sends the |
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results to the standard output, one per line. |
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An expression contains real numbers, function calls, |
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and the following operators: |
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.PP |
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+ - * / ^ |
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.PP |
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Operators are evaluated left to right, except '^', |
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which is right associative. |
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Powers have the highest precedence; multiplication and |
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division are evaluated before addition and subtraction. |
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Expressions can be grouped with parentheses. |
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All values are double precision real. |
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.PP |
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The following library of functions is available: |
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.TP 10n |
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.BR "if(cond, then, else)" |
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if cond is greater than zero, |
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then is evaluated, otherwise else is evaluated. |
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.TP |
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.BR "select(N, a1, a2, ..)" |
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return aN (N is rounded to the nearest integer). |
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If |
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.I N |
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is zero, the number of available arguments is returned. |
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.TP |
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.BR "rand(x)" |
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compute a random number between 0 and 1 based on x. |
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.TP |
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.BR "floor(x)" |
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return largest integer not greater than x. |
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.TP |
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.BR "ceil(x)" |
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return smallest integer not less than x. |
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.TP |
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.BR "sqrt(x)" |
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return square root of x. |
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.TP |
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.BR "exp(x)" |
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compute e to the power of x (e approx = 2.718281828). |
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.TP |
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.BR "log(x)" |
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compute the logarithm of x to the base e. |
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.TP |
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.BR "log10(x)" |
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compute the logarithm of x to the base 10. |
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.TP |
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.BR "sin(x), cos(x), tan(x)" |
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trigonometric functions. |
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.TP |
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.BR "asin(x), acos(x), atan(x)" |
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inverse trigonometric functions. |
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.TP |
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.BR "atan2(y, x)" |
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inverse tangent of y/x (range \-pi to pi). |
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.SH EXAMPLE |
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To pass the square root of two and the sine of .5 to a program: |
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.IP "" .2i |
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program `ev 'sqrt(2)' 'sin(.5)'` |
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.SH AUTHOR |
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Greg Ward |
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.SH "SEE ALSO" |
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icalc(1), rcalc(1) |
