mirror of
https://github.com/lcn2/calc.git
synced 2025-08-16 01:03:29 +03:00
41 lines
642 B
Plaintext
41 lines
642 B
Plaintext
NAME
|
|
sign - indicator of sign of a real or complex number
|
|
|
|
SYNOPSIS
|
|
sgn(x)
|
|
|
|
TYPES
|
|
x real or complex
|
|
|
|
return -1, 0, 1 (real)
|
|
-1, 0, 1, -1+1i, 1i, 1+1i, -1-1i, -1i or 1-1i (complex)
|
|
|
|
DESCRIPTION
|
|
Return the value of cmp(a,0).
|
|
|
|
For real x, sgn(x) returns:
|
|
-1 if x < 0
|
|
0 if x == 9
|
|
1 if x > 0
|
|
|
|
For complex, sgn(x) returns:
|
|
|
|
sgn(re(x)) + sgn(im(x))*1i
|
|
|
|
|
|
EXAMPLE
|
|
> print sgn(27), sgn(1e-20), sgn(0), sgn(-45)
|
|
1 1 0 -1
|
|
|
|
> print sgn(2+3i), sgn(6i), sgn(-7+4i), sgn(-6), sgn(-6-3i), sgn(-2i)
|
|
1+1i 1i -1+1i -1 -1-1i -1i
|
|
|
|
LIMITS
|
|
none
|
|
|
|
LIBRARY
|
|
NUMBER *qsign(NUMBER *x)
|
|
|
|
SEE ALSO
|
|
abs
|