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<TITLE>HPL_daxpy HPL 2.0 Library Functions September 10, 2008</TITLE> |
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ALINK = "#ffff00"> |
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<H1>Name</H1> |
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<B>HPL_daxpy</B> y := y + alpha * x. |
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<H1>Synopsis</H1> |
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<CODE>#include "hpl.h"</CODE><BR><BR> |
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<CODE>void</CODE> |
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<CODE>HPL_daxpy(</CODE> |
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<CODE>const int</CODE> |
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<CODE>N</CODE>, |
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<CODE>const double</CODE> |
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<CODE>ALPHA</CODE>, |
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<CODE>const double *</CODE> |
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<CODE>X</CODE>, |
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<CODE>const int</CODE> |
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<CODE>INCX</CODE>, |
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<CODE>double *</CODE> |
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<CODE>Y</CODE>, |
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<CODE>const int</CODE> |
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<CODE>INCY</CODE> |
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<CODE>);</CODE> |
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<H1>Description</H1> |
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<B>HPL_daxpy</B> |
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scales the vector x by alpha and adds it to y. |
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<H1>Arguments</H1> |
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<PRE>
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N (local input) const int |
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On entry, N specifies the length of the vectors x and y. N |
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must be at least zero. |
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</PRE>
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<PRE>
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ALPHA (local input) const double |
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On entry, ALPHA specifies the scalar alpha. When ALPHA is |
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supplied as zero, then the entries of the incremented array X |
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need not be set on input. |
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</PRE>
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<PRE>
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X (local input) const double * |
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On entry, X is an incremented array of dimension at least |
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( 1 + ( n - 1 ) * abs( INCX ) ) that contains the vector x. |
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</PRE>
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<PRE>
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INCX (local input) const int |
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On entry, INCX specifies the increment for the elements of X. |
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INCX must not be zero. |
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</PRE>
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<PRE>
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Y (local input/output) double * |
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On entry, Y is an incremented array of dimension at least |
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( 1 + ( n - 1 ) * abs( INCY ) ) that contains the vector y. |
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On exit, the entries of the incremented array Y are updated |
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with the scaled entries of the incremented array X. |
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</PRE>
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<PRE>
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INCY (local input) const int |
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On entry, INCY specifies the increment for the elements of Y. |
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INCY must not be zero. |
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</PRE>
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<H1>Example</H1> |
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<CODE>#include "hpl.h"</CODE><BR><BR> |
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<PRE>
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int main(int argc, char *argv[]) |
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{
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double x[3], y[3]; |
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x[0] = 1.0; x[1] = 2.0; x[2] = 3.0; |
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y[0] = 4.0; y[1] = 5.0; y[2] = 6.0; |
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HPL_daxpy( 3, 2.0, x, 1, y, 1 ); |
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printf("y=[%f,%f,%f]\n", y[0], y[1], y[2]);
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exit(0); return(0); |
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} |
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</PRE>
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<H1>See Also</H1> |
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<A HREF="HPL_dcopy.html">HPL_dcopy</A>, |
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<A HREF="HPL_dscal.html">HPL_dscal</A>, |
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<A HREF="HPL_dswap.html">HPL_dswap</A>. |
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