Provided by: liblapack-doc_3.12.0-3build1_all 
NAME
dot - dot: x^H x and x^T x
SYNOPSIS
Functions
complex function cdotc (n, cx, incx, cy, incy)
CDOTC
complex function cdotu (n, cx, incx, cy, incy)
CDOTU
double precision function ddot (n, dx, incx, dy, incy)
DDOT
double precision function dsdot (n, sx, incx, sy, incy)
DSDOT
real function sdot (n, sx, incx, sy, incy)
SDOT
real function sdsdot (n, sb, sx, incx, sy, incy)
SDSDOT
complex *16 function zdotc (n, zx, incx, zy, incy)
ZDOTC
complex *16 function zdotu (n, zx, incx, zy, incy)
ZDOTU
Detailed Description
Function Documentation
complex function cdotc (integer n, complex, dimension(*) cx, integer incx, complex,
dimension(*) cy, integer incy)
CDOTC
Purpose:
CDOTC forms the dot product of two complex vectors
CDOTC = X^H * Y
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 CX
CY
CY is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCY ) )
INCY
INCY is INTEGER
storage spacing between elements of CY
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(*)
complex function cdotu (integer n, complex, dimension(*) cx, integer incx, complex,
dimension(*) cy, integer incy)
CDOTU
Purpose:
CDOTU forms the dot product of two complex vectors
CDOTU = X^T * Y
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 CX
CY
CY is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCY ) )
INCY
INCY is INTEGER
storage spacing between elements of CY
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(*)
double precision function ddot (integer n, double precision, dimension(*) dx, integer incx,
double precision, dimension(*) dy, integer incy)
DDOT
Purpose:
DDOT 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)
DX
DX is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
INCX
INCX is INTEGER
storage spacing between elements of DX
DY
DY is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCY ) )
INCY
INCY is INTEGER
storage spacing between elements of DY
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(*)
double precision function dsdot (integer n, real, dimension(*) sx, integer incx, real,
dimension(*) sy, integer incy)
DSDOT
Purpose:
Compute the inner product of two vectors with extended
precision accumulation and result.
Returns D.P. dot product accumulated in D.P., for S.P. SX and SY
DSDOT = 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)
SX
SX is REAL array, dimension(N)
single precision vector with N elements
INCX
INCX is INTEGER
storage spacing between elements of SX
SY
SY is REAL array, dimension(N)
single precision vector with N elements
INCY
INCY is INTEGER
storage spacing between elements of SY
Returns
DSDOT
DSDOT is DOUBLE PRECISION
DSDOT double precision dot product (zero if N.LE.0)
Author
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
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 style (JL)
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
complex*16 function zdotc (integer n, complex*16, dimension(*) zx, integer incx, complex*16,
dimension(*) zy, integer incy)
ZDOTC
Purpose:
ZDOTC forms the dot product of two complex vectors
ZDOTC = X^H * Y
Parameters
N
N is INTEGER
number of elements in input vector(s)
ZX
ZX is COMPLEX*16 array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
INCX
INCX is INTEGER
storage spacing between elements of ZX
ZY
ZY is COMPLEX*16 array, dimension ( 1 + ( N - 1 )*abs( INCY ) )
INCY
INCY is INTEGER
storage spacing between elements of ZY
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Further Details:
jack dongarra, 3/11/78.
modified 12/3/93, array(1) declarations changed to array(*)
complex*16 function zdotu (integer n, complex*16, dimension(*) zx, integer incx, complex*16,
dimension(*) zy, integer incy)
ZDOTU
Purpose:
ZDOTU forms the dot product of two complex vectors
ZDOTU = X^T * Y
Parameters
N
N is INTEGER
number of elements in input vector(s)
ZX
ZX is COMPLEX*16 array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
INCX
INCX is INTEGER
storage spacing between elements of ZX
ZY
ZY is COMPLEX*16 array, dimension ( 1 + ( N - 1 )*abs( INCY ) )
INCY
INCY is INTEGER
storage spacing between elements of ZY
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Further Details:
jack dongarra, 3/11/78.
modified 12/3/93, array(1) declarations changed to array(*)
Author
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