Subroutine */
| 21047 | } /* clasr_ */ |
| 21048 | |
| 21049 | /* Subroutine */ int classq_(integer *n, complex *x, integer *incx, real * |
| 21050 | scale, real *sumsq) |
| 21051 | { |
| 21052 | /* System generated locals */ |
| 21053 | integer i__1, i__2, i__3; |
| 21054 | real r__1; |
| 21055 | |
| 21056 | /* Local variables */ |
| 21057 | static integer ix; |
| 21058 | static real temp1; |
| 21059 | |
| 21060 | |
| 21061 | /* |
| 21062 | -- LAPACK auxiliary routine (version 3.2) -- |
| 21063 | -- LAPACK is a software package provided by Univ. of Tennessee, -- |
| 21064 | -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
| 21065 | November 2006 |
| 21066 | |
| 21067 | |
| 21068 | Purpose |
| 21069 | ======= |
| 21070 | |
| 21071 | CLASSQ returns the values scl and ssq such that |
| 21072 | |
| 21073 | ( scl**2 )*ssq = x( 1 )**2 +...+ x( n )**2 + ( scale**2 )*sumsq, |
| 21074 | |
| 21075 | where x( i ) = abs( X( 1 + ( i - 1 )*INCX ) ). The value of sumsq is |
| 21076 | assumed to be at least unity and the value of ssq will then satisfy |
| 21077 | |
| 21078 | 1.0 .le. ssq .le. ( sumsq + 2*n ). |
| 21079 | |
| 21080 | scale is assumed to be non-negative and scl returns the value |
| 21081 | |
| 21082 | scl = max( scale, abs( real( x( i ) ) ), abs( aimag( x( i ) ) ) ), |
| 21083 | i |
| 21084 | |
| 21085 | scale and sumsq must be supplied in SCALE and SUMSQ respectively. |
| 21086 | SCALE and SUMSQ are overwritten by scl and ssq respectively. |
| 21087 | |
| 21088 | The routine makes only one pass through the vector X. |
| 21089 | |
| 21090 | Arguments |
| 21091 | ========= |
| 21092 | |
| 21093 | N (input) INTEGER |
| 21094 | The number of elements to be used from the vector X. |
| 21095 | |
| 21096 | X (input) COMPLEX array, dimension (N) |
| 21097 | The vector x as described above. |
| 21098 | x( i ) = X( 1 + ( i - 1 )*INCX ), 1 <= i <= n. |
| 21099 | |
| 21100 | INCX (input) INTEGER |
| 21101 | The increment between successive values of the vector X. |
| 21102 | INCX > 0. |
| 21103 | |
| 21104 | SCALE (input/output) REAL |
| 21105 | On entry, the value scale in the equation above. |
| 21106 | On exit, SCALE is overwritten with the value scl . |