/*  sdcmpi2.cpp  by K.Tsuru  */
// function ID 3511  DRADIX, constant
/********************************
SDouble class
pi/2
Used in Asin(), etc.
*********************************/
#ifndef SN_H
#include "sn.h"
#endif

static SDouble* mpi2 = NULL;    //keep in the static memory
static uint mpi2_size = 0;

void MPi2Free(){        //free the memory of mpi2
    if(mpi2_size == 0) return;
    delete mpi2;        mpi2 = NULL;        mpi2_size = 0;
}

/* pi/2 */
SDouble MPi2(){
    uint ms = SNManager::SNMaxSize(SNManager::REAL);
    if(mpi2_size < ms){
        if(mpi2 == NULL) mpi2 = new SDouble;

        SDouble pi = Pi();
        *mpi2 = DsDiv(pi, 2uL); // pi/2
        mpi2_size = ms;
    }
    return *mpi2;
}