Generates a vector of random variates from a χ2 distribution with probability density function, \(f (X)\), where:
\[f (X) = \frac{X^{\frac{v}{2}-1} e^{-\frac{X}{2}}}{2^{\frac{v}{2}}(\frac{v}{2}-1)!}\]
if \(X > 0\), otherwise \(f (X) = 0\). Here ν is the degrees of freedom, DF.
C Generate 100 values from the Chi-squared distribution
INTEGER LSTATE,N
PARAMETER (LSTATE=16,N=100)
INTEGER I,INFO,SEED(1),STATE(LSTATE) INTEGER DF
DOUBLE PRECISION X(N)
C Set the seed
SEED(1) = 1234
C Read in the distributional parameters
READ(5,*) DF
C Initialize the STATE vector
CALL DRANDINITIALIZE(1,1,SEED,1,STATE,LSTATE,INFO)
C Generate N variates from the Chi-squared distribution
CALL DRANDCHISQUARED(N,DF,STATE,X,INFO)
C Print the results
WRITE(6,*) (X(I),I=1,N)