dot(3) Library Functions Manual dot(3) 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(*) Definition at line 82 of file cdotc.f. 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(*) Definition at line 82 of file cdotu.f. 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(*) Definition at line 81 of file ddot.f. 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) Definition at line 118 of file dsdot.f. 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(*) Definition at line 81 of file sdot.f. 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 Definition at line 112 of file sdsdot.f. 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(*) Definition at line 82 of file zdotc.f. 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(*) Definition at line 82 of file zdotu.f. Author Generated automatically by Doxygen for LAPACK from the source code. LAPACK Version 3.12.0 dot(3)