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(g77-295.info)CMPLX() of DOUBLE PRECISION

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`CMPLX()' of `DOUBLE PRECISION'
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   In accordance with Fortran 90 and at least some (perhaps all) other
compilers, the GNU Fortran language defines `CMPLX()' as always
returning a result that is type `COMPLEX(KIND=1)'.

   This means `CMPLX(D1,D2)', where `D1' and `D2' are `REAL(KIND=2)'
(`DOUBLE PRECISION'), is treated as:

     CMPLX(SNGL(D1), SNGL(D2))

   (It was necessary for Fortran 90 to specify this behavior for
`DOUBLE PRECISION' arguments, since that is the behavior mandated by
FORTRAN 77.)

   The GNU Fortran language also provides the `DCMPLX()' intrinsic,
which is provided by some FORTRAN 77 compilers to construct a `DOUBLE
COMPLEX' entity from of `DOUBLE PRECISION' operands.  However, this
solution does not scale well when more `COMPLEX' types (having various
precisions and ranges) are offered by Fortran implementations.

   Fortran 90 extends the `CMPLX()' intrinsic by adding an extra
argument used to specify the desired kind of complex result.  However,
this solution is somewhat awkward to use, and `g77' currently does not
support it.

   The GNU Fortran language provides a simple way to build a complex
value out of two numbers, with the precise type of the value determined
by the types of the two numbers (via the usual type-promotion
mechanism):

     COMPLEX(REAL, IMAG)

   When REAL and IMAG are the same `REAL' types, `COMPLEX()' performs
no conversion other than to put them together to form a complex result
of the same (complex version of real) type.

   Note: Complex Intrinsic, for more information.