1 @cindex elementary operations
4 The following functions allow for the propagation of errors when
5 combining quantities by multiplication. The functions are declared in
6 the header file @file{gsl_sf_elementary.h}.
8 @comment @deftypefun double gsl_sf_multiply (double @var{x}, double @var{y})
9 @deftypefun int gsl_sf_multiply_e (double @var{x}, double @var{y}, gsl_sf_result * @var{result})
10 This function multiplies @var{x} and @var{y} storing the product and its
11 associated error in @var{result}.
12 @comment Exceptional Return Values: GSL_EOVRFLW, GSL_EUNDRFLW
16 @deftypefun int gsl_sf_multiply_err_e (double @var{x}, double @var{dx}, double @var{y}, double @var{dy}, gsl_sf_result * @var{result})
17 This function multiplies @var{x} and @var{y} with associated absolute
18 errors @var{dx} and @var{dy}. The product
19 @c{$xy \pm xy \sqrt{(dx/x)^2 +(dy/y)^2}$}
20 @math{xy +/- xy \sqrt((dx/x)^2 +(dy/y)^2)}
21 is stored in @var{result}.
22 @comment Exceptional Return Values: GSL_EOVRFLW, GSL_EUNDRFLW