#include "blaswrap.h" #include "f2c.h" /* Subroutine */ int classq_(integer *n, complex *x, integer *incx, real * scale, real *sumsq) { /* -- LAPACK auxiliary routine (version 3.1) -- Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. November 2006 Purpose ======= CLASSQ returns the values scl and ssq such that ( scl**2 )*ssq = x( 1 )**2 +...+ x( n )**2 + ( scale**2 )*sumsq, where x( i ) = abs( X( 1 + ( i - 1 )*INCX ) ). The value of sumsq is assumed to be at least unity and the value of ssq will then satisfy 1.0 .le. ssq .le. ( sumsq + 2*n ). scale is assumed to be non-negative and scl returns the value scl = max( scale, abs( real( x( i ) ) ), abs( aimag( x( i ) ) ) ), i scale and sumsq must be supplied in SCALE and SUMSQ respectively. SCALE and SUMSQ are overwritten by scl and ssq respectively. The routine makes only one pass through the vector X. Arguments ========= N (input) INTEGER The number of elements to be used from the vector X. X (input) COMPLEX array, dimension (N) The vector x as described above. x( i ) = X( 1 + ( i - 1 )*INCX ), 1 <= i <= n. INCX (input) INTEGER The increment between successive values of the vector X. INCX > 0. SCALE (input/output) REAL On entry, the value scale in the equation above. On exit, SCALE is overwritten with the value scl . SUMSQ (input/output) REAL On entry, the value sumsq in the equation above. On exit, SUMSQ is overwritten with the value ssq . ===================================================================== Parameter adjustments */ /* System generated locals */ integer i__1, i__2, i__3; real r__1; /* Builtin functions */ double r_imag(complex *); /* Local variables */ static integer ix; static real temp1; --x; /* Function Body */ if (*n > 0) { i__1 = (*n - 1) * *incx + 1; i__2 = *incx; for (ix = 1; i__2 < 0 ? ix >= i__1 : ix <= i__1; ix += i__2) { i__3 = ix; if (x[i__3].r != 0.f) { i__3 = ix; temp1 = (r__1 = x[i__3].r, dabs(r__1)); if (*scale < temp1) { /* Computing 2nd power */ r__1 = *scale / temp1; *sumsq = *sumsq * (r__1 * r__1) + 1; *scale = temp1; } else { /* Computing 2nd power */ r__1 = temp1 / *scale; *sumsq += r__1 * r__1; } } if (r_imag(&x[ix]) != 0.f) { temp1 = (r__1 = r_imag(&x[ix]), dabs(r__1)); if (*scale < temp1) { /* Computing 2nd power */ r__1 = *scale / temp1; *sumsq = *sumsq * (r__1 * r__1) + 1; *scale = temp1; } else { /* Computing 2nd power */ r__1 = temp1 / *scale; *sumsq += r__1 * r__1; } } /* L10: */ } } return 0; /* End of CLASSQ */ } /* classq_ */