LOG(3F) LOG(3F)
log, alog, dlog, qlog, clog, zlog - FORTRAN natural logarithm intrinsic
function
real r1, r2
double precision dp1, dp2
real*16 qp1, qp2
complex cx1, cx2
complex*16 cd1, cd2
r2 = alog(r1)
r2 = log(r1)
dp2 = dlog(dp1)
dp2 = log(dp1)
qp2 = qlog(qp1)
qp2 = log(qp1)
cx2 = clog(cx1)
cx2 = log(cx1)
cd2 = zlog(cd1)
cd2 = log(cd1)
alog returns the real natural logarithm of its real argument. dlog
returns the double-precision natural logarithm of its double-precision
argument. qlog returns the real*16 natural logarithm of its real*16
argument. The argument of alog, dlog, and qlog must be greater than
zero. clog returns the complex logarithm of its complex argument. The
argument of clog must not be (0.,0.). The range of the imaginary part of
clog is: -pi < imaginary part <= pi. zlog returns the complex*16
logarithm of its complex*16 argument. The generic function log becomes a
call to alog, dlog, qlog, clog, or zlog depending on the type of its
argument.
exp(3M).
Page 1
ALOG(3M) Last changed: 1-6-98
ALOG, DLOG, CLOG, CDLOG - Computes natural logarithm
UNICOS and UNICOS/mk systems:
ALOG ([X=]x)
DLOG ([X=]x)
CLOG ([X=]x)
UNICOS and IRIX systems:
CDLOG ([X=]x)
UNICOS, UNICOS/mk, and IRIX systems
Fortran 90
CDLOG is a compiler extension to Fortran 90.
LOG is the generic function name. ALOG, DLOG, and CLOG are intrinsic
and elemental functions for CF90.
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 CDLOG 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.
These functions evaluate y = ln(x).
CF90 [Toc] [Back]
CDLOG is called implicitly by the Fortran 90 compiler as a result of a
generic ALOG call with a complex double-precision argument.
CAL Register Usage (Cray Research Systems Only)
Scalar ALOG: ALOG% (call-by-register)
on entry (S1) = argument
on exit (S1) = result
Vector ALOG: %ALOG% (call-by-register)
on entry (V1) = argument vector
on exit (V1) = result vector
Scalar DLOG: DLOG% (call-by-register)
on entry (S1) and (S2) = argument
on exit (S1) and (S2) = result
Vector DLOG: %DLOG% (call-by-register)
on entry (V1) and (V2) = argument vector
on exit (V1) and (V2) = result vector
Scalar CLOG: CLOG% (call-by-register)
on entry (S1) and (S2) = argument
on exit (S1) and (S2) = result
Vector CLOG: %CLOG% (call-by-register)
on entry (V1) and (V2) = argument vector
on exit (V1) and (V2) = result vector
Scalar CDLOG: CDLOG% (call-by-register)
on entry (S1), (S2), (S3), (S4) = argument
on exit (S1), (S2), (S3), (S4) = result
Vector CDLOG: %CDLOG% (call-by-register)
on entry (V1), (V2), (V3), (V4) = argument vector
on exit (V1), (V2), (V3), (V4) = result vector
Argument Range 2450
infinity is approximately 10
308
On UNICOS/mk systems, infinity is approximately 10
ALOG, DLOG: 0 < x < infinity
CLOG: x must not be (0,0).
CDLOG (all systems except UNICOS/mk systems): x must not be (0,0).
CDLOG is an outmoded routine for CF90. 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 ALOG, DLOG, and CLOG intrinsic can be passed as an
argument. The name of the CDLOG intrinsic cannot be passed as an
argument.
ALOG returns the real natural logarithm of its real argument.
DLOG returns the double-precision natural logarithm of its
double-precision argument.
CLOG returns the complex natural logarithm of its complex argument.
CDLOG returns the complex double-precision natural logorithm of its
complex double-precision argument.
On CRAY T90 systems that support IEEE arithmetic, the following return
values occur:
ALOG(0) = - infinity
ALOG(-0) = NaN
ALOG(x) = NaN if - infinity <= x < 0
ALOG( infinity ) = infinity
Intrinsic Procedures Reference Manual, publication SR-2138, for the
printed version of this man page.
ALOG(3M) Last changed: 1-6-98
ALOG, DLOG, CLOG, CDLOG - Computes natural logarithm
UNICOS and UNICOS/mk systems:
ALOG ([X=]x)
DLOG ([X=]x)
CLOG ([X=]x)
UNICOS and IRIX systems:
CDLOG ([X=]x)
UNICOS, UNICOS/mk, and IRIX systems
Fortran 90
CDLOG is a compiler extension to Fortran 90.
LOG is the generic function name. ALOG, DLOG, and CLOG are intrinsic
and elemental functions for CF90.
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 CDLOG 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.
These functions evaluate y = ln(x).
CF90 [Toc] [Back]
CDLOG is called implicitly by the Fortran 90 compiler as a result of a
generic ALOG call with a complex double-precision argument.
CAL Register Usage (Cray Research Systems Only)
Scalar ALOG: ALOG% (call-by-register)
on entry (S1) = argument
on exit (S1) = result
Vector ALOG: %ALOG% (call-by-register)
on entry (V1) = argument vector
on exit (V1) = result vector
Scalar DLOG: DLOG% (call-by-register)
on entry (S1) and (S2) = argument
on exit (S1) and (S2) = result
Vector DLOG: %DLOG% (call-by-register)
on entry (V1) and (V2) = argument vector
on exit (V1) and (V2) = result vector
Scalar CLOG: CLOG% (call-by-register)
on entry (S1) and (S2) = argument
on exit (S1) and (S2) = result
Vector CLOG: %CLOG% (call-by-register)
on entry (V1) and (V2) = argument vector
on exit (V1) and (V2) = result vector
Scalar CDLOG: CDLOG% (call-by-register)
on entry (S1), (S2), (S3), (S4) = argument
on exit (S1), (S2), (S3), (S4) = result
Vector CDLOG: %CDLOG% (call-by-register)
on entry (V1), (V2), (V3), (V4) = argument vector
on exit (V1), (V2), (V3), (V4) = result vector
Argument Range 2450
infinity is approximately 10
308
On UNICOS/mk systems, infinity is approximately 10
ALOG, DLOG: 0 < x < infinity
CLOG: x must not be (0,0).
CDLOG (all systems except UNICOS/mk systems): x must not be (0,0).
CDLOG is an outmoded routine for CF90. 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 ALOG, DLOG, and CLOG intrinsic can be passed as an
argument. The name of the CDLOG intrinsic cannot be passed as an
argument.
ALOG returns the real natural logarithm of its real argument.
DLOG returns the double-precision natural logarithm of its
double-precision argument.
CLOG returns the complex natural logarithm of its complex argument.
CDLOG returns the complex double-precision natural logorithm of its
complex double-precision argument.
On CRAY T90 systems that support IEEE arithmetic, the following return
values occur:
ALOG(0) = - infinity
ALOG(-0) = NaN
ALOG(x) = NaN if - infinity <= x < 0
ALOG( infinity ) = infinity
Intrinsic Procedures Reference Manual, publication SR-2138, for the
printed version of this man page.
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