SUMMARY

Evaluates simple arithmetic expressions.

SYNTAX

EVALUATE {TO TERM|name} {v} op v {op v ...}

where op is one of the following:

ADD|SUBTRACT|MULTIPLY|DIVIDE|POWER|

SQRT|EXP|ALOG|ALOG10|SIN|ASIN|

COS|ACOS|TAN|ATAN|

EQ|NE|LE|GE|LT|GT

INPUT

TO TERM:	Result is written to the user's terminal.
TO name:	Result is written to the blackboard variable name.
v:	An floating point or integer number. Since all arithmetic is done in floating point, integers are converted to floating point numbers.
op:	One of the arithmetic or logical operators listed above.

ALTERNATE FORMS

+ may be substituted for ADD_
- for SUBTRACT
* for MULTIPLY
/ for DIVIDE
** for POWER

Be sure and place spaces around each operator.

DEFAULT VALUES

EVALUATE TO TERM 1. * 1.

DESCRIPTION

This command lets you evaluate arithmetic and logical expressions. The arithmetic expression can be a compound one, containing more than one operator. In this case the expression is evaluated left to right. There is no nesting capability. A logical expression can contain only one operand. The result of evaluating this expression can be written to the user's terminal or to a specified blackboard variable. This blackboard variable can later be used directly in other commands. This is especially useful when writing macros. You can also get the value of a blackboard variable using the GETBB command.

EXAMPLES

Let's first check to see if SAC knows its multiplication tables:

u:  EVALUATE 2. * 2.
s:  4.0000
u:  EVALUATE 2. * 3.
s:  6.0000

Now let's convert an angle in degrees to radians and then find its tangent:

u:  EVALUATE 45 * 3.14159 / 180
s:  0.78540
u:  EVALUATE TAN 0.78540
s:  0.9982

That's pretty close. Notice that when you omit the first variable, SAC assumes it's value to be 1. Why does SAC not get the same answer in the following example?

u:  EVALUATE TAN 45 * 3.14159 / 180
s:  0.02827

Finally let's repeat an earlier example but this time use the blackboard:

u:  EVALUATE TO TEMP1 45 * 3.14159 / 180
u:  EVALUATE TAN %TEMP1
s:  0.9982

LIMITATIONS

Maximum number of operators in a single expression is 10.

SEE COMMANDS

GETBB See the section on "Macros" in the SAC Users Manual.

LATEST REVISION

April 15, 1987 (Version 10.1)