OpenBLAS/interface/rotmg.c

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/**************************************************************************************
* 2014/05/02 Saar
* 	fixed two bugs as reported by Brendan Tracey 
*	Test with lapack-3.5.0	: OK 
*
**************************************************************************************/


#include "common.h"
#ifdef FUNCTION_PROFILE
#include "functable.h"
#endif

#define  GAM     4096.e0
#define  GAMSQ   16777216.e0
#define  RGAMSQ  5.9604645e-8

#define  TWO 2.e0

#ifdef DOUBLE
#define ABS(x) fabs(x)
#else
#define ABS(x) fabsf(x)
#endif

#ifndef CBLAS

void NAME(FLOAT *dd1, FLOAT *dd2, FLOAT *dx1, FLOAT *DY1, FLOAT *dparam){

  FLOAT	dy1 = *DY1;

#else

void CNAME(FLOAT *dd1, FLOAT *dd2, FLOAT *dx1, FLOAT dy1, FLOAT *dparam){

#endif

	FLOAT du, dp1, dp2, dq2, dq1, dh11, dh21, dh12, dh22, dflag, dtemp;

	if(*dd1 < ZERO)
	{
		dflag = -ONE;
		dh11  = ZERO;
		dh12  = ZERO;
		dh21  = ZERO;
		dh22  = ZERO;

		*dd1  = ZERO;
		*dd2  = ZERO;
		*dx1  = ZERO;
	}
	else
	{
		dp2 = *dd2 * dy1;
		if(dp2 == ZERO)
		{
			dflag = -TWO;
			dparam[0] = dflag;
			return;
		}
		dp1 = *dd1 * *dx1;
		dq2 =  dp2 * dy1;
		dq1 =  dp1 * *dx1;
		if(ABS(dq1) > ABS(dq2))
		{
			dh21 = -  dy1 / *dx1;
			dh12 =    dp2 /  dp1;

			du   = ONE - dh12 * dh21;
			if(du > ZERO)
			{
				dflag = ZERO;
				*dd1  = *dd1 / du;
				*dd2  = *dd2 / du;
				*dx1  = *dx1 * du;

			}
		}
		else
		{
			if(dq2 < ZERO)
			{
				dflag = -ONE;
				
				dh11  = ZERO;
				dh12  = ZERO;
				dh21  = ZERO;
				dh22  = ZERO;

				*dd1  = ZERO;
				*dd2  = ZERO;
				*dx1  = ZERO;
			}
			else
			{
				dflag = ONE;

				dh11  =  dp1 /  dp2;
				dh22  = *dx1 /  dy1;
				du    =  ONE + dh11 * dh22;
				dtemp = *dd2 / du;

				*dd2  = *dd1 / du;
				*dd1  = dtemp;
				*dx1  = dy1 * du;
			}			
		}


		if(*dd1 != ZERO)
		{
			while( (*dd1 <= RGAMSQ) || (*dd1 >= GAMSQ) )
			{
				if(dflag == ZERO)
				{
					dh11  =  ONE;
					dh22  =  ONE;
					dflag = -ONE;
				}
				else
				{
					if(dflag == ONE)
					{
						dh21  = -ONE;
						dh12  =  ONE;
						dflag = -ONE;
					}
				}
				if( *dd1 <= RGAMSQ )
				{
					*dd1  = *dd1 * (GAM * GAM);
					*dx1  = *dx1 / GAM;
					dh11  = dh11 / GAM;
					dh12  = dh12 / GAM;
				}
				else
				{
					*dd1  = *dd1 / (GAM * GAM);
					*dx1  = *dx1 * GAM;
					dh11  = dh11 * GAM;
					dh12  = dh12 * GAM;
				}
			}
		}
			
		if(*dd2 != ZERO)
		{
			while( (ABS(*dd2) <= RGAMSQ) || (ABS(*dd2) >= GAMSQ) )
			{
				if(dflag == ZERO)
				{
					dh11  =  ONE;
					dh22  =  ONE;
					dflag = -ONE;
				}
				else
				{
					if(dflag == ONE)
					{
						dh21  = -ONE;
						dh12  =  ONE;
						dflag = -ONE;
					}
				}
				if( ABS(*dd2) <= RGAMSQ )
				{
					*dd2  = *dd2 * (GAM * GAM);
					dh21  = dh21 / GAM;
					dh22  = dh22 / GAM;
				}
				else
				{
					*dd2  = *dd2 / (GAM * GAM);
					dh21  = dh21 * GAM;
					dh22  = dh22 * GAM;
				}
			}
		}
					
	}

	if(dflag < ZERO)
	{
		dparam[1] = dh11;
		dparam[2] = dh21;
		dparam[3] = dh12;
		dparam[4] = dh22;
	}
	else
	{
		if(dflag == ZERO)
		{
			dparam[2] = dh21;
			dparam[3] = dh12;
		}
		else
		{
			dparam[1] = dh11;
			dparam[4] = dh22;
		}
	}


	dparam[0] = dflag;
	return;
}