IEEE_COPY_SIGN(3I) Last changed: 1-6-98
NAME
IEEE_COPY_SIGN - Returns x with the sign of y
SYNOPSIS
IEEE_COPY_SIGN ([X=]x, [Y=]y)
IMPLEMENTATION
UNICOS/mk and IRIX systems
CRAY T90 systems that support IEEE floating-point arithmetic
STANDARDS
CF90 and MIPSpro 7 Fortran 90 compiler extension to Fortran 90
IEEE Standard for Binary Floating-point Arithmetic
DESCRIPTION
The IEEE_COPY_SIGN intrinsic function returns x with the sign of y.
For example,
ABS(x) = IEEE_COPY_SIGN(x, 1.0) even if x is a NaN.
The Fortran 90 standard SIGN(3M) intrinsic function produces the same
result as IEEE_COPY_SIGN on systems that support IEEE floating-point
arithmetic.
This function accepts the following arguments:
x Must be of type real.
y Must be of type real. If x is a scalar, y must be a scalar.
If x is an array, y can be scalar or an array of the same
shape as x.
IEEE_COPY_SIGN is an elemental function. The name of this intrinsic
cannot be passed as an argument.
NOTES
The IEEE intrinsic procedures use the named constants contained in a
system module, so you must include one of the following statements in
your program:
* On UNICOS and UNICOS/mk systems: USE CRI_IEEE_DEFINITIONS
* On UNICOS, UNICOS/mk, and IRIX systems: USE FTN_IEEE_DEFINITIONS
The CRI_IEEE_DEFINITIONS module is obsolescent. It will be removed
for the CF90 4.0 release.
RETURN VALUES
The return value is of the same type and type parameter as x. If x is
an array, the result is an array of the same shape as x.
If x is scalar, the result is a scalar that has the same value as x
but with the sign of y.
If x is an array and y is scalar, the result is an array in which each
element has the value of the corresponding element of x and the sign
of y.
If x is an array and y is an array, the result is an array in which
each element has the value of x but the sign of y .
i i
EXAMPLES
Example 1. Each element of x now has its original value but with the
sign of each corresponding element of y:
REAL x(10), y(10)
... ! Compute X and Y.
x = IEEE_COPY_SIGN(x, y)
Example 2. The following PRINT statement is executed on a system that
supports the IEEE standard for floating-point arithmetic:
PRINT *, 'IEEE_COPY_SIGN(5.0,-0.0)
The output of the preceding PRINT statement is -5.0.
SEE ALSOSIGN(3M)
Intrinsic Procedures Reference Manual, publication SR-2138, for the
printed version of this man page.
