/* -- translated by f2c (version 19940927). You must link the resulting object file with the libraries: -lf2c -lm (in that order) */ #include "f2c.h" real snrm2_(integer *n, real *x, integer *incx) { /* System generated locals */ integer i__1, i__2; real ret_val, r__1; /* Builtin functions */ double sqrt(doublereal); /* Local variables */ static real norm, scale, absxi; static integer ix; static real ssq; /* SNRM2 returns the euclidean norm of a vector via the function name, so that SNRM2 := sqrt( x'*x ) -- This version written on 25-October-1982. Modified on 14-October-1993 to inline the call to SLASSQ. Sven Hammarling, Nag Ltd. Parameter adjustments Function Body */ #define X(I) x[(I)-1] if (*n < 1 || *incx < 1) { norm = 0.f; } else if (*n == 1) { norm = dabs(X(1)); } else { scale = 0.f; ssq = 1.f; /* The following loop is equivalent to this call to the LAPACK auxiliary routine: CALL SLASSQ( N, X, INCX, SCALE, SSQ ) */ i__1 = (*n - 1) * *incx + 1; i__2 = *incx; for (ix = 1; *incx < 0 ? ix >= (*n-1)**incx+1 : ix <= (*n-1)**incx+1; ix += *incx) { if (X(ix) != 0.f) { absxi = (r__1 = X(ix), dabs(r__1)); if (scale < absxi) { /* Computing 2nd power */ r__1 = scale / absxi; ssq = ssq * (r__1 * r__1) + 1.f; scale = absxi; } else { /* Computing 2nd power */ r__1 = absxi / scale; ssq += r__1 * r__1; } } /* L10: */ } norm = scale * sqrt(ssq); } ret_val = norm; return ret_val; /* End of SNRM2. */ } /* snrm2_ */