### Entering C expressions

C expressions can be used for parameter values. Blocks that
allow an expression as a parameter are evaluated only once at the start of the
simulation (T=0) and will be entered as a constant for code generation. To
evaluate an expression at each time step, use the expression block.

You can call elementary mathematical functions like acos,
asin, atan2, cos, cosh, exp, fabs, log, log10, pow, sin, sinh, sqrt, tan, and
tanh. For example, if you enter pow (2,3) to the Gain parameter on the gain
block, the result is 8.

Embed also interprets *pi* as the universal constant
π.

If you are unfamiliar with the C language and want to learn
how to enter mathematical functions in C format, see *C:* *A
Software Engineering Approach*, (Springer-Verlag, 1990).

Most numeric data can be expressed using the arithmetic
operators + - * / and the usual rules of precedence. For example:

2 * (5 + 4) = 18

2 * 5 + 4 = 14

2 + 5 * 4 = 22

#### Treatment of
constants

Embed treats numeric constants a bit differently
than standard C: constants with no decimal point are still considered to be
floating-point numbers.