float.c

PostgreSQL7.4.6 for Linux

	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	errno = 0;
	result = asin(arg1);
	if (errno != 0
#ifdef HAVE_FINITE
		|| !finite(result)
#endif
		)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}


/*
 *		datan			- returns the arctan of arg1 (radians)
 */
Datum
datan(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	errno = 0;
	result = atan(arg1);
	if (errno != 0
#ifdef HAVE_FINITE
		|| !finite(result)
#endif
		)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}


/*
 *		atan2			- returns the arctan2 of arg1 (radians)
 */
Datum
datan2(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);
	float8		result;

	errno = 0;
	result = atan2(arg1, arg2);
	if (errno != 0
#ifdef HAVE_FINITE
		|| !finite(result)
#endif
		)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}


/*
 *		dcos			- returns the cosine of arg1 (radians)
 */
Datum
dcos(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	errno = 0;
	result = cos(arg1);
	if (errno != 0
#ifdef HAVE_FINITE
		|| !finite(result)
#endif
		)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}


/*
 *		dcot			- returns the cotangent of arg1 (radians)
 */
Datum
dcot(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	errno = 0;
	result = tan(arg1);
	if (errno != 0 || result == 0.0
#ifdef HAVE_FINITE
		|| !finite(result)
#endif
		)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

	result = 1.0 / result;
	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}


/*
 *		dsin			- returns the sine of arg1 (radians)
 */
Datum
dsin(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	errno = 0;
	result = sin(arg1);
	if (errno != 0
#ifdef HAVE_FINITE
		|| !finite(result)
#endif
		)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}


/*
 *		dtan			- returns the tangent of arg1 (radians)
 */
Datum
dtan(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	errno = 0;
	result = tan(arg1);
	if (errno != 0
#ifdef HAVE_FINITE
		|| !finite(result)
#endif
		)
		ereport(ERROR,
				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
				 errmsg("input is out of range")));

	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}


/*
 *		degrees		- returns degrees converted from radians
 */
Datum
degrees(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	result = arg1 * (180.0 / M_PI);

	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}


/*
 *		dpi				- returns the constant PI
 */
Datum
dpi(PG_FUNCTION_ARGS)
{
	PG_RETURN_FLOAT8(M_PI);
}


/*
 *		radians		- returns radians converted from degrees
 */
Datum
radians(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float8		result;

	result = arg1 * (M_PI / 180.0);

	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}


/*
 *		drandom		- returns a random number
 */
Datum
drandom(PG_FUNCTION_ARGS)
{
	float8		result;

	/* result 0.0-1.0 */
	result = ((double) random()) / ((double) MAX_RANDOM_VALUE);

	PG_RETURN_FLOAT8(result);
}


/*
 *		setseed		- set seed for the random number generator
 */
Datum
setseed(PG_FUNCTION_ARGS)
{
	float8		seed = PG_GETARG_FLOAT8(0);
	int			iseed = (int) (seed * MAX_RANDOM_VALUE);

	srandom((unsigned int) iseed);

	PG_RETURN_INT32(iseed);
}



/*
 *		=========================
 *		FLOAT AGGREGATE OPERATORS
 *		=========================
 *
 *		float8_accum	- accumulate for AVG(), STDDEV(), etc
 *		float4_accum	- same, but input data is float4
 *		float8_avg		- produce final result for float AVG()
 *		float8_variance - produce final result for float VARIANCE()
 *		float8_stddev	- produce final result for float STDDEV()
 *
 * The transition datatype for all these aggregates is a 3-element array
 * of float8, holding the values N, sum(X), sum(X*X) in that order.
 *
 * Note that we represent N as a float to avoid having to build a special
 * datatype.  Given a reasonable floating-point implementation, there should
 * be no accuracy loss unless N exceeds 2 ^ 52 or so (by which time the
 * user will have doubtless lost interest anyway...)
 */

static float8 *
check_float8_array(ArrayType *transarray, const char *caller)
{
	/*
	 * We expect the input to be a 3-element float array; verify that. We
	 * don't need to use deconstruct_array() since the array data is just
	 * going to look like a C array of 3 float8 values.
	 */
	if (ARR_NDIM(transarray) != 1 ||
		ARR_DIMS(transarray)[0] != 3 ||
		ARR_ELEMTYPE(transarray) != FLOAT8OID)
		elog(ERROR, "%s: expected 3-element float8 array", caller);
	return (float8 *) ARR_DATA_PTR(transarray);
}

Datum
float8_accum(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	float8		newval = PG_GETARG_FLOAT8(1);
	float8	   *transvalues;
	float8		N,
				sumX,
				sumX2;
	Datum		transdatums[3];
	ArrayType  *result;

	transvalues = check_float8_array(transarray, "float8_accum");
	N = transvalues[0];
	sumX = transvalues[1];
	sumX2 = transvalues[2];

	N += 1.0;
	sumX += newval;
	sumX2 += newval * newval;

	transdatums[0] = Float8GetDatumFast(N);
	transdatums[1] = Float8GetDatumFast(sumX);
	transdatums[2] = Float8GetDatumFast(sumX2);

	result = construct_array(transdatums, 3,
							 FLOAT8OID,
						 sizeof(float8), false /* float8 byval */ , 'd');

	PG_RETURN_ARRAYTYPE_P(result);
}

Datum
float4_accum(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	float4		newval4 = PG_GETARG_FLOAT4(1);
	float8	   *transvalues;
	float8		N,
				sumX,
				sumX2,
				newval;
	Datum		transdatums[3];
	ArrayType  *result;

	transvalues = check_float8_array(transarray, "float4_accum");
	N = transvalues[0];
	sumX = transvalues[1];
	sumX2 = transvalues[2];

	/* Do arithmetic in float8 for best accuracy */
	newval = newval4;

	N += 1.0;
	sumX += newval;
	sumX2 += newval * newval;

	transdatums[0] = Float8GetDatumFast(N);
	transdatums[1] = Float8GetDatumFast(sumX);
	transdatums[2] = Float8GetDatumFast(sumX2);

	result = construct_array(transdatums, 3,
							 FLOAT8OID,
						 sizeof(float8), false /* float8 byval */ , 'd');

	PG_RETURN_ARRAYTYPE_P(result);
}

Datum
float8_avg(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	float8	   *transvalues;
	float8		N,
				sumX;

	transvalues = check_float8_array(transarray, "float8_avg");
	N = transvalues[0];
	sumX = transvalues[1];
	/* ignore sumX2 */

	/* SQL92 defines AVG of no values to be NULL */
	if (N == 0.0)
		PG_RETURN_NULL();

	PG_RETURN_FLOAT8(sumX / N);
}

Datum
float8_variance(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	float8	   *transvalues;
	float8		N,
				sumX,
				sumX2,
				numerator;

	transvalues = check_float8_array(transarray, "float8_variance");
	N = transvalues[0];
	sumX = transvalues[1];
	sumX2 = transvalues[2];

	/* Sample variance is undefined when N is 0 or 1, so return NULL */
	if (N <= 1.0)
		PG_RETURN_NULL();

	numerator = N * sumX2 - sumX * sumX;

	/* Watch out for roundoff error producing a negative numerator */
	if (numerator <= 0.0)
		PG_RETURN_FLOAT8(0.0);

	PG_RETURN_FLOAT8(numerator / (N * (N - 1.0)));
}

Datum
float8_stddev(PG_FUNCTION_ARGS)
{
	ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
	float8	   *transvalues;
	float8		N,
				sumX,
				sumX2,
				numerator;

	transvalues = check_float8_array(transarray, "float8_stddev");
	N = transvalues[0];
	sumX = transvalues[1];
	sumX2 = transvalues[2];

	/* Sample stddev is undefined when N is 0 or 1, so return NULL */
	if (N <= 1.0)
		PG_RETURN_NULL();

	numerator = N * sumX2 - sumX * sumX;

	/* Watch out for roundoff error producing a negative numerator */
	if (numerator <= 0.0)
		PG_RETURN_FLOAT8(0.0);

	PG_RETURN_FLOAT8(sqrt(numerator / (N * (N - 1.0))));
}


/*
 *		====================================
 *		MIXED-PRECISION ARITHMETIC OPERATORS
 *		====================================
 */

/*
 *		float48pl		- returns arg1 + arg2
 *		float48mi		- returns arg1 - arg2
 *		float48mul		- returns arg1 * arg2
 *		float48div		- returns arg1 / arg2
 */
Datum
float48pl(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);
	float8		result;

	result = arg1 + arg2;
	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}

Datum
float48mi(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);
	float8		result;

	result = arg1 - arg2;
	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}

Datum
float48mul(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);
	float8		result;

	result = arg1 * arg2;
	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}

Datum
float48div(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);
	float8		result;

	if (arg2 == 0.0)
		ereport(ERROR,
				(errcode(ERRCODE_DIVISION_BY_ZERO),
				 errmsg("division by zero")));

	result = arg1 / arg2;
	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}

/*
 *		float84pl		- returns arg1 + arg2
 *		float84mi		- returns arg1 - arg2
 *		float84mul		- returns arg1 * arg2
 *		float84div		- returns arg1 / arg2
 */
Datum
float84pl(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);
	float8		result;

	result = arg1 + arg2;

	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}

Datum
float84mi(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);
	float8		result;

	result = arg1 - arg2;

	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}

Datum
float84mul(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);
	float8		result;

	result = arg1 * arg2;

	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}

Datum
float84div(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);
	float8		result;

	if (arg2 == 0.0)
		ereport(ERROR,
				(errcode(ERRCODE_DIVISION_BY_ZERO),
				 errmsg("division by zero")));

	result = arg1 / arg2;

	CheckFloat8Val(result);
	PG_RETURN_FLOAT8(result);
}

/*
 *		====================
 *		COMPARISON OPERATORS
 *		====================
 */

/*
 *		float48{eq,ne,lt,le,gt,ge}		- float4/float8 comparison operations
 */
Datum
float48eq(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) == 0);
}

Datum
float48ne(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) != 0);
}

Datum
float48lt(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) < 0);
}

Datum
float48le(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) <= 0);
}

Datum
float48gt(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) > 0);
}

Datum
float48ge(PG_FUNCTION_ARGS)
{
	float4		arg1 = PG_GETARG_FLOAT4(0);
	float8		arg2 = PG_GETARG_FLOAT8(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) >= 0);
}

/*
 *		float84{eq,ne,lt,le,gt,ge}		- float8/float4 comparison operations
 */
Datum
float84eq(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) == 0);
}

Datum
float84ne(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) != 0);
}

Datum
float84lt(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) < 0);
}

Datum
float84le(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) <= 0);
}

Datum
float84gt(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) > 0);
}

Datum
float84ge(PG_FUNCTION_ARGS)
{
	float8		arg1 = PG_GETARG_FLOAT8(0);
	float4		arg2 = PG_GETARG_FLOAT4(1);

	PG_RETURN_BOOL(float8_cmp_internal(arg1, arg2) >= 0);
}

/* ========== PRIVATE ROUTINES ========== */

#ifndef HAVE_CBRT
static double
cbrt(double x)
{
	int			isneg = (x < 0.0);
	double		tmpres = pow(fabs(x), (double) 1.0 / (double) 3.0);

	return isneg ? -tmpres : tmpres;
}

#endif   /* !HAVE_CBRT */