SQRT(3M) Last changed: 1-6-98
NAME
SQRT, DSQRT, CSQRT, CDSQRT - Computes square root
SYNOPSIS
UNICOS and UNICOS/mk systems:
SQRT ([X=]x)
DSQRT ([X=]x)
CSQRT ([X=]x)
UNICOS and IRIX systems:
CDSQRT ([X=]x)
IMPLEMENTATION
UNICOS, UNICOS/mk, and IRIX systems
STANDARDS
Fortran 90
CDSQRT is a compiler extension to Fortran 90.
DESCRIPTION
SQRT is the generic function name. These functions are elemental
functions for the CF90 compiler.
A vector version of this intrinsic exists on UNICOS and UNICOS/mk
systems. On UNICOS/mk systems, the vector version of this intrinsic
is used when -h vector3 (C compiler) or -O vector3 or -O3 (Fortran
compiler) has been specified on the compiler command line.
The entry point CDSQRT is provided for support in other languages. It
is not recognized as an intrinsic function; therefore, you must use
the CDIR$ VFUNCTION directive to allow vectorization.
CDSQRT is called implicitly by the Fortran 90 compiler as a result of
a generic SQRT call with a complex double-precision argument.
1/2
These functions evaluate y = x .
CAL Register Usage (Cray Research Systems Only)
Scalar SQRT: SQRT% (call-by-register)
on entry (S1) = argument
on exit (S1) = result
Vector SQRT: %SQRT% (call-by-register)
on entry (V1) = argument vector
on exit (V1) = result vector
Scalar DSQRT: DSQRT% (call-by-register)
on entry (S1) and (S2) = argument
on exit (S1) and (S2) = result
Vector DSQRT: %DSQRT% (call-by-register)
on entry (V1) and (V2) = argument vector
on exit (V1) and (V2) = result vector
Scalar CSQRT: CSQRT% (call-by-register)
on entry (S1) and (S2) = argument
on exit (S1) and (S2) = result
Vector CSQRT: %CSQRT% (call-by-register)
on entry (V1) and (V2) = argument vector
on exit (V1) and (V2) = result vector
Argument Range
SQRT, DSQRT:
2450
0 <= x < infinity (infinity is approximately 10 )
308
On UNICOS/mk systems, infinity is approximately 10
CSQRT:
|x | < infinity, |x | < infinity
r i
CDSQRT:
|x | < infinity, |x | < infinity
r i
NOTESCDSQRT is an outmoded routine for the CF90 compiler. Refer to the
Fortran Language Reference Manual, Volume 3, publication SR-3905, for
information about outmoded features and their preferred standard
alternatives.
The name of the SQRT, DSQRT, and CSQRT intrinsic can be passed as an
argument. The name of the CDSQRT intrinsic cannot be passed as an
argument.
RETURN VALUES
SQRT returns the real square root of its real argument.
DSQRT returns the double-precision square root of its double-precision
argument.
CSQRT returns the complex square root of its complex argument.
CDSQRT returns the complex double-precision square root of its complex
double-precision argument.
On CRAY T90 systems that support IEEE arithmetic, the following return
values occur:
SQRT(0) = 0
SQRT(-0) = -0
SQRT(x) = NaN if x < 0
SQRT(NaN) = NaN
SQRT( infinity ) = infinity
SEE ALSO
Intrinsic Procedures Reference Manual, publication SR-2138, for the
printed version of this man page.
