Math Functions
There are a lot of built-in
mathematical functions in Silk. All the functions take double as an
argument and return double as the result.
1. _fun("math_acos", x)
math_acos returns the arc cosine of x in radians.
2. _fun("math_asin", x)
math_asin returns the arc sine of x in radians.
3. _fun("math_atan", x)
math_atan returns the arc tangent of x in radians.
4. _fun("math_atan2", y, x)
math_atan2 returns the arc tangent in radians of y/x based on the signs of both values to determine the correct quadrant.
5. _fun("math_cos", x)
math_cos returns the cosine of a radian angle x.
6. _fun("math_cosh", x)
math_cosh returns the hyperbolic cosine of x.
7. _fun("math_sin", x)
math_sin returns the sine of a radian angle x.
8. _fun("math_sinh", x)
math_sinh returns the hyperbolic sine of x.
9. _fun("math_tanh", x)
math_tanh returns the hyperbolic tangent of x.
10. _fun("math_exp", x)
math_exp returns the value of e raised to the xth power.
11. _fun("math_frexp", x)
The
returned value is an array which has 2 elements, the first one is the
mantissa and the second one is the exponent.
12. _fun("math_ldexp", x, e)
math_ldexp returns x multiplied by 2 raised to the power of e.
13. _fun("math_log", x)
math_log returns the natural logarithm (base-e logarithm) of x.
14. _fun("math_log10", x)
math_log10 returns the common logarithm (base-10 logarithm) of x.
15. _fun("math_modf", x)
The
returned value is an array which has 2 elements, the first
one is the integer component, and the second one is the
fraction component (part after the decimal).
16. _fun("math_pow", x, y)
math_pow returns x raised to the power of y.
17. _fun("math_sqrt", x)
math_sqrt returns the square root of x.
18. _fun("math_fabs", x)
math_fabs returns the absolute value of x.。
19. _fun("math_floor", x)
math_floor returns the largest integer value less than or equal to x.
20. _fun("math_ceil", x)
math_ceil returns the smallest integer value greater than or equal to x.
21. _fun("math_fmod", x, y)
math_fmod returns the remainder of x divided by y.
Here are some samples for math functions：
main()
{
PI=3.14159265;
x = 60.0;
val = PI / 180.0;
ret = _fun("math_cos", x*val );
printf("The cos of %lf is %lf \n", x, ret);
x = 45.0;
val = PI / 180;
ret = _fun("math_sin", x*val );
printf("The sin of %lf is %lf \n", x, ret);
x = 0.65;
n = 3;
ret = _fun("math_ldexp",x ,n);
printf("%f * 2^%d = %f\n", x, n, ret);
x = 1024;
ret = _fun("math_frexp",x);
printf("x = %d = %.2lf * 2^%d\n", x, ret[0], ret[1]);
x = 8.123456;
ret = _fun("math_modf",x);
printf("The part of interger = %lf\n", ret[0]);
printf("The part of fraction = %lf \n", ret[1]);
ret=_fun("math_pow",8,3);
printf("8 ^ 3 = %lf\n", ret);
ret=_fun("math_fabs",-3.05);
printf("fabs(-3.05) = %lf\n",ret);
x = 2.3;
ret=_fun("math_log",x);
printf("log(%lf) = %lf\n", x, ret);
x = 100000;
ret=_fun("math_log10",x);
printf("log10(%d) = %lf\n", x, ret);
x = 2;
ret=_fun("math_sqrt",x);
printf("The square root of %d is %lf\n", x, ret );
a = 9.2;
b = 3.8;
ret=_fun("math_fmod",a,b);
printf("The remainder of %f / %f is %lf\n", a, b, ret);
}