Floating-point quantities are normally displayed in standard decimal form, with scientific notation used if the exponent is especially high or low. All significant digits are normally displayed. The commands in this section allow you to choose among several alternative display formats for floats.
The d n
(calc-normal-notation) command selects the normal
display format. All significant figures in a number are
displayed. With a positive numeric prefix, numbers are rounded if
necessary to that number of significant digits. With a negative
numerix prefix, the specified number of significant digits less
than the current precision is used. (Thus C-u -2 d n
displays 10 digits if the current precision is 12.)
The d f
(calc-fix-notation) command selects fixed-point
notation. The numeric argument is the number of digits after the
decimal point, zero or more. This format will relax into
scientific notation if a nonzero number would otherwise have been
rounded all the way to zero. Specifying a negative number of
digits is the same as for a positive number, except that small
nonzero numbers will be rounded to zero rather than switching to
scientific notation.
The d
s (calc-sci-notation) command selects
scientific notation. A positive argument sets the number of
significant figures displayed, of which one will be before and
the rest after the decimal point. A negative argument works the
same as for d n format. The default is to display all
significant digits.
The d
e (calc-eng-notation) command selects
engineering notation. This is similar to scientific notation
except that the exponent is rounded down to a multiple of three,
with from one to three digits before the decimal point. An
optional numeric prefix sets the number of significant digits to
display, as for d s.
It is important to distinguish between the current precision and the current display format. After the commands C-u 10 p and C-u 6 d n the Calculator computes all results to ten significant figures but displays only six. (In fact, intermediate calculations are often carried to one or two more significant figures, but values placed on the stack will be rounded down to ten figures.) Numbers are never actually rounded to the display precision for storage, except by commands like C-k and C-x * y which operate on the actual displayed text in the Calculator buffer.
The d .
(calc-point-char) command selects the character used
as a decimal point. Normally this is a period; users in some
countries may wish to change this to a comma. Note that this is
only a display style; on entry, periods must always be used to
denote floating-point numbers, and commas to separate elements in
a list.