DZNRM2 man page on IRIX

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SNRM2(3S)							     SNRM2(3S)

NAME
     SNRM2, DNRM2, SCNRM2, DZNRM2 - Computes the Euclidean norm of a vector

SYNOPSIS
     Single precision

	  Fortran:
	       real SNRM2
	       real enrm
	       enrm = SNRM2 (n, x, incx)

	  C/C++:
	       #include <scsl_blas.h>
	       float snrm2 (int n, float *x, int incx);

     Double precision

	  Fortran:
	       double precision DNRM2
	       double precision enrm
	       enrm = DNRM2 (n, xi, incx)

	  C/C++:
	       #include <scsl_blas.h>
	       double dnrm2 (int n, double *x, int incx);

     Single precision complex

	  Fortran:
	       real SCNRM2
	       real enrm
	       enrm = SCNRM2 (n, x, incx)

	  C/C++:
	       #include <scsl_blas.h>
	       float scnrm2 (int n, scsl_complex *x, int incx);

	  C++ STL:
	       #include <complex.h>
	       #include <scsl_blas.h>
	       float scnrm2 (int n, complex<float> *x, int incx);

     Double precision complex

	  Fortran:
	       double precision DZNRM2
	       double precision enrm
	       enrm = DZNRM2 (n, xi, incx)

	  C/C++:
	       #include <scsl_blas.h>
	       double dznrm2 (int n, scsl_zomplex *x, int incx);

									Page 1

SNRM2(3S)							     SNRM2(3S)

	  C++ STL:
	       #include <complex.h>
	       #include <scsl_blas.h>
	       double dznrm2 (int n, complex<double> *x, int incx);

IMPLEMENTATION
     These routines are part of the SCSL Scientific Library and can be loaded
     using either the -lscs or the -lscs_mp option.  The -lscs_mp option
     directs the linker to use the multi-processor version of the library.

     When linking to SCSL with -lscs or -lscs_mp, the default integer size is
     4 bytes (32 bits). Another version of SCSL is available in which integers
     are 8 bytes (64 bits).  This version allows the user access to larger
     memory sizes and helps when porting legacy Cray codes.  It can be loaded
     by using the -lscs_i8 option or the -lscs_i8_mp option. A program may use
     only one of the two versions; 4-byte integer and 8-byte integer library
     calls cannot be mixed.

     The C and C++ prototypes shown above are appropriate for the 4-byte
     integer version of SCSL. When using the 8-byte integer version, the
     variables of type int become long long and the <scsl_blas_i8.h> header
     file should be included.

DESCRIPTION
     SNRM2/DNRM2 computes the Euclidean (l2) norm of a real vector, as
     follows:

	  enrm <- ||x||	  =
		       2

		 T	      n	     2
	  sqrt (x x) = sqrt (Sum * x  )
			     i=1    i

     where x is a real vector, and xT denotes the transpose of x.

     SCNRM2/DZNRM2 computes the Euclidean (l2) norm of a complex vector, as
     follows:

	  enrm <- ||x||	 =
		       2
		 H	      n	 _
	  sqrt (x x) = sqrt (Sum x x )
			     i=1  i i

     where x is a complex vector, and xH denotes the conjugate transpose of x.

									Page 2

SNRM2(3S)							     SNRM2(3S)

     See the NOTES section of this man page for information about the
     interpretation of the data types described in the following arguments.

     These functions have the following arguments:

     enrm      Result.	(output)
	       SNRM2: Single precision result.
	       DNRM2: Double precision result.
	       SCNRM2: Single precision complex result.
	       DZNRM2:	Double precision complex result.
	       Result (Euclidean norm).	 If n <= 0, enrm is set to 0.

     n	       Integer.	 (input)
	       Number of elements in the operand vector.

     x	       Array of dimension (n-1) * |incx| + 1.  (input)
	       SNRM2: Single precision array.
	       DNRM2: Double precision array.
	       SCNRM2: Single precision complex array.
	       DZNRM2:	Double precision complex array.
	       Array x contains the operand vector.

     incx      Integer.	 (input)
	       Increment between elements of x.	 If incx = 0, the results will
	       be unpredictable.

NOTES
     These routines are Level 1 Basic Linear Algebra Subprograms (Level 1
     BLAS).

     When working backward (incx < 0), each routine starts at the end of the
     vector and moves backward, as follows:

	  x(1-incx * (n-1)), x(1-incx * (n-2)), ..., x(1)

   Data Types
     The following data types are described in this documentation:

	  Term Used			Data type

     Fortran:

	  Array dimensioned n		x(n)

	  Integer			INTEGER (INTEGER*8 for -lscs_i8[_mp])

	  Single precision		REAL

	  Double precision		DOUBLE PRECISION

									Page 3

SNRM2(3S)							     SNRM2(3S)

	  Single precision complex	COMPLEX

	  Double precision complex	DOUBLE COMPLEX

     C/C++:

	  Array dimensioned n		x[n]

	  Integer			int (long long for -lscs_i8[_mp])

	  Single precision		float

	  Double precision		double

	  Single precision complex	scsl_complex

	  Double precision complex	scsl_zomplex

     C++ STL:

	  Array dimensioned n		x[n]

	  Integer			int (long long for -lscs_i8[_mp])

	  Single precision		float

	  Double precision		double

	  Single precision complex	complex<float>

	  Double precision complex	complex<double>

SEE ALSO
     INTRO_SCSL(3S), INTRO_BLAS1(3S)

     INTRO_CBLAS(3S) for information about using the C interface to Fortran 77
     Basic Linear Algebra Subprograms (legacy BLAS) set forth by the Basic
     Linear Algebra Subprograms Technical Forum.

									Page 4

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