LAPACK  3.10.0 LAPACK: Linear Algebra PACKage

## ◆ clarnv()

 subroutine clarnv ( integer IDIST, integer, dimension( 4 ) ISEED, integer N, complex, dimension( * ) X )

CLARNV returns a vector of random numbers from a uniform or normal distribution.

Purpose:
``` CLARNV returns a vector of n random complex numbers from a uniform or
normal distribution.```
Parameters
 [in] IDIST ``` IDIST is INTEGER Specifies the distribution of the random numbers: = 1: real and imaginary parts each uniform (0,1) = 2: real and imaginary parts each uniform (-1,1) = 3: real and imaginary parts each normal (0,1) = 4: uniformly distributed on the disc abs(z) < 1 = 5: uniformly distributed on the circle abs(z) = 1``` [in,out] ISEED ``` ISEED is INTEGER array, dimension (4) On entry, the seed of the random number generator; the array elements must be between 0 and 4095, and ISEED(4) must be odd. On exit, the seed is updated.``` [in] N ``` N is INTEGER The number of random numbers to be generated.``` [out] X ``` X is COMPLEX array, dimension (N) The generated random numbers.```
Further Details:
```  This routine calls the auxiliary routine SLARUV to generate random
real numbers from a uniform (0,1) distribution, in batches of up to
128 using vectorisable code. The Box-Muller method is used to
transform numbers from a uniform to a normal distribution.```

Definition at line 98 of file clarnv.f.

99 *
100 * -- LAPACK auxiliary routine --
101 * -- LAPACK is a software package provided by Univ. of Tennessee, --
102 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
103 *
104 * .. Scalar Arguments ..
105  INTEGER IDIST, N
106 * ..
107 * .. Array Arguments ..
108  INTEGER ISEED( 4 )
109  COMPLEX X( * )
110 * ..
111 *
112 * =====================================================================
113 *
114 * .. Parameters ..
115  REAL ZERO, ONE, TWO
116  parameter( zero = 0.0e+0, one = 1.0e+0, two = 2.0e+0 )
117  INTEGER LV
118  parameter( lv = 128 )
119  REAL TWOPI
120  parameter( twopi = 6.28318530717958647692528676655900576839e+0 )
121 * ..
122 * .. Local Scalars ..
123  INTEGER I, IL, IV
124 * ..
125 * .. Local Arrays ..
126  REAL U( LV )
127 * ..
128 * .. Intrinsic Functions ..
129  INTRINSIC cmplx, exp, log, min, sqrt
130 * ..
131 * .. External Subroutines ..
132  EXTERNAL slaruv
133 * ..
134 * .. Executable Statements ..
135 *
136  DO 60 iv = 1, n, lv / 2
137  il = min( lv / 2, n-iv+1 )
138 *
139 * Call SLARUV to generate 2*IL real numbers from a uniform (0,1)
140 * distribution (2*IL <= LV)
141 *
142  CALL slaruv( iseed, 2*il, u )
143 *
144  IF( idist.EQ.1 ) THEN
145 *
146 * Copy generated numbers
147 *
148  DO 10 i = 1, il
149  x( iv+i-1 ) = cmplx( u( 2*i-1 ), u( 2*i ) )
150  10 CONTINUE
151  ELSE IF( idist.EQ.2 ) THEN
152 *
153 * Convert generated numbers to uniform (-1,1) distribution
154 *
155  DO 20 i = 1, il
156  x( iv+i-1 ) = cmplx( two*u( 2*i-1 )-one,
157  \$ two*u( 2*i )-one )
158  20 CONTINUE
159  ELSE IF( idist.EQ.3 ) THEN
160 *
161 * Convert generated numbers to normal (0,1) distribution
162 *
163  DO 30 i = 1, il
164  x( iv+i-1 ) = sqrt( -two*log( u( 2*i-1 ) ) )*
165  \$ exp( cmplx( zero, twopi*u( 2*i ) ) )
166  30 CONTINUE
167  ELSE IF( idist.EQ.4 ) THEN
168 *
169 * Convert generated numbers to complex numbers uniformly
170 * distributed on the unit disk
171 *
172  DO 40 i = 1, il
173  x( iv+i-1 ) = sqrt( u( 2*i-1 ) )*
174  \$ exp( cmplx( zero, twopi*u( 2*i ) ) )
175  40 CONTINUE
176  ELSE IF( idist.EQ.5 ) THEN
177 *
178 * Convert generated numbers to complex numbers uniformly
179 * distributed on the unit circle
180 *
181  DO 50 i = 1, il
182  x( iv+i-1 ) = exp( cmplx( zero, twopi*u( 2*i ) ) )
183  50 CONTINUE
184  END IF
185  60 CONTINUE
186  RETURN
187 *
188 * End of CLARNV
189 *
subroutine slaruv(ISEED, N, X)
SLARUV returns a vector of n random real numbers from a uniform distribution.
Definition: slaruv.f:95
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