00001 /* slargv.f -- translated by f2c (version 20061008). 00002 You must link the resulting object file with libf2c: 00003 on Microsoft Windows system, link with libf2c.lib; 00004 on Linux or Unix systems, link with .../path/to/libf2c.a -lm 00005 or, if you install libf2c.a in a standard place, with -lf2c -lm 00006 -- in that order, at the end of the command line, as in 00007 cc *.o -lf2c -lm 00008 Source for libf2c is in /netlib/f2c/libf2c.zip, e.g., 00009 00010 http://www.netlib.org/f2c/libf2c.zip 00011 */ 00012 00013 #include "f2c.h" 00014 #include "blaswrap.h" 00015 00016 /* Subroutine */ int slargv_(integer *n, real *x, integer *incx, real *y, 00017 integer *incy, real *c__, integer *incc) 00018 { 00019 /* System generated locals */ 00020 integer i__1; 00021 00022 /* Builtin functions */ 00023 double sqrt(doublereal); 00024 00025 /* Local variables */ 00026 real f, g; 00027 integer i__; 00028 real t; 00029 integer ic, ix, iy; 00030 real tt; 00031 00032 00033 /* -- LAPACK auxiliary routine (version 3.2) -- */ 00034 /* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */ 00035 /* November 2006 */ 00036 00037 /* .. Scalar Arguments .. */ 00038 /* .. */ 00039 /* .. Array Arguments .. */ 00040 /* .. */ 00041 00042 /* Purpose */ 00043 /* ======= */ 00044 00045 /* SLARGV generates a vector of real plane rotations, determined by */ 00046 /* elements of the real vectors x and y. For i = 1,2,...,n */ 00047 00048 /* ( c(i) s(i) ) ( x(i) ) = ( a(i) ) */ 00049 /* ( -s(i) c(i) ) ( y(i) ) = ( 0 ) */ 00050 00051 /* Arguments */ 00052 /* ========= */ 00053 00054 /* N (input) INTEGER */ 00055 /* The number of plane rotations to be generated. */ 00056 00057 /* X (input/output) REAL array, */ 00058 /* dimension (1+(N-1)*INCX) */ 00059 /* On entry, the vector x. */ 00060 /* On exit, x(i) is overwritten by a(i), for i = 1,...,n. */ 00061 00062 /* INCX (input) INTEGER */ 00063 /* The increment between elements of X. INCX > 0. */ 00064 00065 /* Y (input/output) REAL array, */ 00066 /* dimension (1+(N-1)*INCY) */ 00067 /* On entry, the vector y. */ 00068 /* On exit, the sines of the plane rotations. */ 00069 00070 /* INCY (input) INTEGER */ 00071 /* The increment between elements of Y. INCY > 0. */ 00072 00073 /* C (output) REAL array, dimension (1+(N-1)*INCC) */ 00074 /* The cosines of the plane rotations. */ 00075 00076 /* INCC (input) INTEGER */ 00077 /* The increment between elements of C. INCC > 0. */ 00078 00079 /* ===================================================================== */ 00080 00081 /* .. Parameters .. */ 00082 /* .. */ 00083 /* .. Local Scalars .. */ 00084 /* .. */ 00085 /* .. Intrinsic Functions .. */ 00086 /* .. */ 00087 /* .. Executable Statements .. */ 00088 00089 /* Parameter adjustments */ 00090 --c__; 00091 --y; 00092 --x; 00093 00094 /* Function Body */ 00095 ix = 1; 00096 iy = 1; 00097 ic = 1; 00098 i__1 = *n; 00099 for (i__ = 1; i__ <= i__1; ++i__) { 00100 f = x[ix]; 00101 g = y[iy]; 00102 if (g == 0.f) { 00103 c__[ic] = 1.f; 00104 } else if (f == 0.f) { 00105 c__[ic] = 0.f; 00106 y[iy] = 1.f; 00107 x[ix] = g; 00108 } else if (dabs(f) > dabs(g)) { 00109 t = g / f; 00110 tt = sqrt(t * t + 1.f); 00111 c__[ic] = 1.f / tt; 00112 y[iy] = t * c__[ic]; 00113 x[ix] = f * tt; 00114 } else { 00115 t = f / g; 00116 tt = sqrt(t * t + 1.f); 00117 y[iy] = 1.f / tt; 00118 c__[ic] = t * y[iy]; 00119 x[ix] = g * tt; 00120 } 00121 ic += *incc; 00122 iy += *incy; 00123 ix += *incx; 00124 /* L10: */ 00125 } 00126 return 0; 00127 00128 /* End of SLARGV */ 00129 00130 } /* slargv_ */