Scroll to navigation

single_blas_level1(3) LAPACK single_blas_level1(3)

NAME

single_blas_level1 - real

SYNOPSIS

Functions


real function sasum (N, SX, INCX)
SASUM subroutine saxpy (N, SA, SX, INCX, SY, INCY)
SAXPY real function scabs1 (Z)
SCABS1 real function scasum (N, CX, INCX)
SCASUM subroutine scopy (N, SX, INCX, SY, INCY)
SCOPY real function sdot (N, SX, INCX, SY, INCY)
SDOT real function sdsdot (N, SB, SX, INCX, SY, INCY)
SDSDOT subroutine srot (N, SX, INCX, SY, INCY, C, S)
SROT subroutine srotm (N, SX, INCX, SY, INCY, SPARAM)
SROTM subroutine srotmg (SD1, SD2, SX1, SY1, SPARAM)
SROTMG subroutine sscal (N, SA, SX, INCX)
SSCAL subroutine sswap (N, SX, INCX, SY, INCY)
SSWAP

Detailed Description

This is the group of real LEVEL 1 BLAS routines.

Function Documentation

real function sasum (integer N, real, dimension(*) SX, integer INCX)

SASUM

Purpose:



    SASUM takes the sum of the absolute values.


    uses unrolled loops for increment equal to one.

Parameters

N 



          N is INTEGER


         number of elements in input vector(s)

SX



          SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )

INCX



          INCX is INTEGER


         storage spacing between elements of SX

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Further Details:



     jack dongarra, linpack, 3/11/78.


     modified 3/93 to return if incx .le. 0.


     modified 12/3/93, array(1) declarations changed to array(*)

subroutine saxpy (integer N, real SA, real, dimension(*) SX, integer INCX, real, dimension(*) SY, integer INCY)

SAXPY

Purpose:



    SAXPY constant times a vector plus a vector.


    uses unrolled loops for increments equal to one.

Parameters

N 



          N is INTEGER


         number of elements in input vector(s)

SA



          SA is REAL


           On entry, SA specifies the scalar alpha.

SX



          SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )

INCX



          INCX is INTEGER


         storage spacing between elements of SX

SY



          SY is REAL array, dimension ( 1 + ( N - 1 )*abs( INCY ) )

INCY



          INCY is INTEGER


         storage spacing between elements of SY

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Further Details:



     jack dongarra, linpack, 3/11/78.


     modified 12/3/93, array(1) declarations changed to array(*)

real function scabs1 (complex Z)

SCABS1

Purpose:



 SCABS1 computes |Re(.)| + |Im(.)| of a complex number

Parameters

Z 



          Z is COMPLEX

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

real function scasum (integer N, complex, dimension(*) CX, integer INCX)

SCASUM

Purpose:



    SCASUM takes the sum of the (|Re(.)| + |Im(.)|)'s of a complex vector and


    returns a single precision result.

Parameters

N 



          N is INTEGER


         number of elements in input vector(s)

CX



          CX is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCX ) )

INCX



          INCX is INTEGER


         storage spacing between elements of SX

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Further Details:



     jack dongarra, linpack, 3/11/78.


     modified 3/93 to return if incx .le. 0.


     modified 12/3/93, array(1) declarations changed to array(*)

subroutine scopy (integer N, real, dimension(*) SX, integer INCX, real, dimension(*) SY, integer INCY)

SCOPY

Purpose:



    SCOPY copies a vector, x, to a vector, y.


    uses unrolled loops for increments equal to 1.

Parameters

N 



          N is INTEGER


         number of elements in input vector(s)

SX



          SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )

INCX



          INCX is INTEGER


         storage spacing between elements of SX

SY



          SY is REAL array, dimension ( 1 + ( N - 1 )*abs( INCY ) )

INCY



          INCY is INTEGER


         storage spacing between elements of SY

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Further Details:



     jack dongarra, linpack, 3/11/78.


     modified 12/3/93, array(1) declarations changed to array(*)

real function sdot (integer N, real, dimension(*) SX, integer INCX, real, dimension(*) SY, integer INCY)

SDOT

Purpose:



    SDOT forms the dot product of two vectors.


    uses unrolled loops for increments equal to one.

Parameters

N 



          N is INTEGER


         number of elements in input vector(s)

SX



          SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )

INCX



          INCX is INTEGER


         storage spacing between elements of SX

SY



          SY is REAL array, dimension ( 1 + ( N - 1 )*abs( INCY ) )

INCY



          INCY is INTEGER


         storage spacing between elements of SY

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Further Details:



     jack dongarra, linpack, 3/11/78.


     modified 12/3/93, array(1) declarations changed to array(*)

real function sdsdot (integer N, real SB, real, dimension(*) SX, integer INCX, real, dimension(*) SY, integer INCY)

SDSDOT

Purpose:



   Compute the inner product of two vectors with extended


   precision accumulation.


   Returns S.P. result with dot product accumulated in D.P.


   SDSDOT = SB + sum for I = 0 to N-1 of SX(LX+I*INCX)*SY(LY+I*INCY),


   where LX = 1 if INCX .GE. 0, else LX = 1+(1-N)*INCX, and LY is


   defined in a similar way using INCY.

Parameters

N 



          N is INTEGER


          number of elements in input vector(s)

SB



          SB is REAL


          single precision scalar to be added to inner product

SX



          SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )


          single precision vector with N elements

INCX



          INCX is INTEGER


          storage spacing between elements of SX

SY



          SY is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )


          single precision vector with N elements

INCY



          INCY is INTEGER


          storage spacing between elements of SY

Author

Lawson, C. L., (JPL), Hanson, R. J., (SNLA),

Kincaid, D. R., (U. of Texas), Krogh, F. T., (JPL)

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Further Details:



    REFERENCES


    C. L. Lawson, R. J. Hanson, D. R. Kincaid and F. T.


    Krogh, Basic linear algebra subprograms for Fortran


    usage, Algorithm No. 539, Transactions on Mathematical


    Software 5, 3 (September 1979), pp. 308-323.


    REVISION HISTORY  (YYMMDD)


    791001  DATE WRITTEN


    890531  Changed all specific intrinsics to generic.  (WRB)


    890831  Modified array declarations.  (WRB)


    890831  REVISION DATE from Version 3.2


    891214  Prologue converted to Version 4.0 format.  (BAB)


    920310  Corrected definition of LX in DESCRIPTION.  (WRB)


    920501  Reformatted the REFERENCES section.  (WRB)


    070118  Reformat to LAPACK coding style

subroutine srot (integer N, real, dimension(*) SX, integer INCX, real, dimension(*) SY, integer INCY, real C, real S)

SROT

Purpose:



    applies a plane rotation.

Parameters

N 



          N is INTEGER


         number of elements in input vector(s)

SX



          SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )

INCX



          INCX is INTEGER


         storage spacing between elements of SX

SY



          SY is REAL array, dimension ( 1 + ( N - 1 )*abs( INCY ) )

INCY



          INCY is INTEGER


         storage spacing between elements of SY

C



          C is REAL

S



          S is REAL

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Further Details:



     jack dongarra, linpack, 3/11/78.


     modified 12/3/93, array(1) declarations changed to array(*)

subroutine srotm (integer N, real, dimension(*) SX, integer INCX, real, dimension(*) SY, integer INCY, real, dimension(5) SPARAM)

SROTM

Purpose:



    APPLY THE MODIFIED GIVENS TRANSFORMATION, H, TO THE 2 BY N MATRIX


    (SX**T) , WHERE **T INDICATES TRANSPOSE. THE ELEMENTS OF SX ARE IN


    (SX**T)


    SX(LX+I*INCX), I = 0 TO N-1, WHERE LX = 1 IF INCX .GE. 0, ELSE


    LX = (-INCX)*N, AND SIMILARLY FOR SY USING USING LY AND INCY.


    WITH SPARAM(1)=SFLAG, H HAS ONE OF THE FOLLOWING FORMS..


    SFLAG=-1.E0     SFLAG=0.E0        SFLAG=1.E0     SFLAG=-2.E0


      (SH11  SH12)    (1.E0  SH12)    (SH11  1.E0)    (1.E0  0.E0)


    H=(          )    (          )    (          )    (          )


      (SH21  SH22),   (SH21  1.E0),   (-1.E0 SH22),   (0.E0  1.E0).


    SEE  SROTMG FOR A DESCRIPTION OF DATA STORAGE IN SPARAM.

Parameters

N 



          N is INTEGER


         number of elements in input vector(s)

SX



          SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )

INCX



          INCX is INTEGER


         storage spacing between elements of SX

SY



          SY is REAL array, dimension ( 1 + ( N - 1 )*abs( INCY ) )

INCY



          INCY is INTEGER


         storage spacing between elements of SY

SPARAM



          SPARAM is REAL array, dimension (5)


     SPARAM(1)=SFLAG


     SPARAM(2)=SH11


     SPARAM(3)=SH21


     SPARAM(4)=SH12


     SPARAM(5)=SH22

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

subroutine srotmg (real SD1, real SD2, real SX1, real SY1, real, dimension(5) SPARAM)

SROTMG

Purpose:



    CONSTRUCT THE MODIFIED GIVENS TRANSFORMATION MATRIX H WHICH ZEROS


    THE SECOND COMPONENT OF THE 2-VECTOR  (SQRT(SD1)*SX1,SQRT(SD2)*>    SY2)**T.


    WITH SPARAM(1)=SFLAG, H HAS ONE OF THE FOLLOWING FORMS..


    SFLAG=-1.E0     SFLAG=0.E0        SFLAG=1.E0     SFLAG=-2.E0


      (SH11  SH12)    (1.E0  SH12)    (SH11  1.E0)    (1.E0  0.E0)


    H=(          )    (          )    (          )    (          )


      (SH21  SH22),   (SH21  1.E0),   (-1.E0 SH22),   (0.E0  1.E0).


    LOCATIONS 2-4 OF SPARAM CONTAIN SH11,SH21,SH12, AND SH22


    RESPECTIVELY. (VALUES OF 1.E0, -1.E0, OR 0.E0 IMPLIED BY THE


    VALUE OF SPARAM(1) ARE NOT STORED IN SPARAM.)


    THE VALUES OF GAMSQ AND RGAMSQ SET IN THE DATA STATEMENT MAY BE


    INEXACT.  THIS IS OK AS THEY ARE ONLY USED FOR TESTING THE SIZE


    OF SD1 AND SD2.  ALL ACTUAL SCALING OF DATA IS DONE USING GAM.

Parameters

SD1 



          SD1 is REAL

SD2



          SD2 is REAL

SX1



          SX1 is REAL

SY1



          SY1 is REAL

SPARAM



          SPARAM is REAL array, dimension (5)


     SPARAM(1)=SFLAG


     SPARAM(2)=SH11


     SPARAM(3)=SH21


     SPARAM(4)=SH12


     SPARAM(5)=SH22

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

subroutine sscal (integer N, real SA, real, dimension(*) SX, integer INCX)

SSCAL

Purpose:



    SSCAL scales a vector by a constant.


    uses unrolled loops for increment equal to 1.

Parameters

N 



          N is INTEGER


         number of elements in input vector(s)

SA



          SA is REAL


           On entry, SA specifies the scalar alpha.

SX



          SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )

INCX



          INCX is INTEGER


         storage spacing between elements of SX

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Further Details:



     jack dongarra, linpack, 3/11/78.


     modified 3/93 to return if incx .le. 0.


     modified 12/3/93, array(1) declarations changed to array(*)

subroutine sswap (integer N, real, dimension(*) SX, integer INCX, real, dimension(*) SY, integer INCY)

SSWAP

Purpose:



    SSWAP interchanges two vectors.


    uses unrolled loops for increments equal to 1.

Parameters

N 



          N is INTEGER


         number of elements in input vector(s)

SX



          SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )

INCX



          INCX is INTEGER


         storage spacing between elements of SX

SY



          SY is REAL array, dimension ( 1 + ( N - 1 )*abs( INCY ) )

INCY



          INCY is INTEGER


         storage spacing between elements of SY

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Further Details:



     jack dongarra, linpack, 3/11/78.


     modified 12/3/93, array(1) declarations changed to array(*)

Author

Generated automatically by Doxygen for LAPACK from the source code.

Sun Nov 27 2022 Version 3.11.0