eval, deval

eval(obj[,prec])

deval(obj)

:: Evaluate obj numerically.

return

number or expression

obj

general expression

prec

integer

• Evaluates the value of the functions contained in obj as far as possible.
• deval returns double float. Rational numbers remain unchanged in results from eval.
• In eval the computation is done by PARI. (See section pari.) In deval the computation is done by the C math library.
• deval cannot handle complex numbers.
• When prec is specified, computation will be performed with a precision of about prec-digits. If prec is not specified, computation is performed with the precision set currently. (See section setprec.)
• Currently available numerical functions are listed below. Note they are only a small part of whole PARI functions.

  sin, cos, tan, asin, acos, atan, sinh, cosh, tanh, asinh, acosh, atanh, exp, log, pow(a,b) (a^b)

• Symbols for special values are as the followings. Note that @i cannot be handled by deval.

  @i

  unit of imaginary number

  @pi

  the number pi, the ratio of circumference to diameter

  @e

  Napier's number (exp(1))

[118] eval(exp(@pi*@i));   
-1.0000000000000000000000000000
[119] eval(2^(1/2));
1.414213562373095048763788073031
[120] eval(sin(@pi/3));
0.86602540378443864674620506632
[121] eval(sin(@pi/3)-3^(1/2)/2,50);
-2.78791084448179148471 E-58
[122] eval(1/2);
1/2
[123] deval(sin(1)^2+cos(1)^2);
1

References

section ctrl, section setprec, section pari.

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