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halfvec.c
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#include "postgres.h"
#include <math.h>
#include "bitvec.h"
#include "catalog/pg_type.h"
#include "common/shortest_dec.h"
#include "fmgr.h"
#include "halfutils.h"
#include "halfvec.h"
#include "lib/stringinfo.h"
#include "libpq/pqformat.h"
#include "port.h" /* for strtof() */
#include "sparsevec.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/float.h"
#include "utils/lsyscache.h"
#include "utils/numeric.h"
#include "vector.h"
#define STATE_DIMS(x) (ARR_DIMS(x)[0] - 1)
#define CreateStateDatums(dim) palloc(sizeof(Datum) * (dim + 1))
/*
* Get a half from a message buffer
*/
static half
pq_getmsghalf(StringInfo msg)
{
union
{
half h;
uint16 i;
} swap;
swap.i = pq_getmsgint(msg, 2);
return swap.h;
}
/*
* Append a half to a StringInfo buffer
*/
static void
pq_sendhalf(StringInfo buf, half h)
{
union
{
half h;
uint16 i;
} swap;
swap.h = h;
pq_sendint16(buf, swap.i);
}
/*
* Ensure same dimensions
*/
static inline void
CheckDims(HalfVector * a, HalfVector * b)
{
if (a->dim != b->dim)
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("different halfvec dimensions %d and %d", a->dim, b->dim)));
}
/*
* Ensure expected dimensions
*/
static inline void
CheckExpectedDim(int32 typmod, int dim)
{
if (typmod != -1 && typmod != dim)
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("expected %d dimensions, not %d", typmod, dim)));
}
/*
* Ensure valid dimensions
*/
static inline void
CheckDim(int dim)
{
if (dim < 1)
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("halfvec must have at least 1 dimension")));
if (dim > HALFVEC_MAX_DIM)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("halfvec cannot have more than %d dimensions", HALFVEC_MAX_DIM)));
}
/*
* Ensure finite element
*/
static inline void
CheckElement(half value)
{
if (HalfIsNan(value))
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("NaN not allowed in halfvec")));
if (HalfIsInf(value))
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("infinite value not allowed in halfvec")));
}
/*
* Allocate and initialize a new half vector
*/
HalfVector *
InitHalfVector(int dim)
{
HalfVector *result;
int size;
size = HALFVEC_SIZE(dim);
result = (HalfVector *) palloc0(size);
SET_VARSIZE(result, size);
result->dim = dim;
return result;
}
/*
* Check for whitespace, since array_isspace() is static
*/
static inline bool
halfvec_isspace(char ch)
{
if (ch == ' ' ||
ch == '\t' ||
ch == '\n' ||
ch == '\r' ||
ch == '\v' ||
ch == '\f')
return true;
return false;
}
/*
* Check state array
*/
static float8 *
CheckStateArray(ArrayType *statearray, const char *caller)
{
if (ARR_NDIM(statearray) != 1 ||
ARR_DIMS(statearray)[0] < 1 ||
ARR_HASNULL(statearray) ||
ARR_ELEMTYPE(statearray) != FLOAT8OID)
elog(ERROR, "%s: expected state array", caller);
return (float8 *) ARR_DATA_PTR(statearray);
}
/*
* Convert textual representation to internal representation
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_in);
Datum
halfvec_in(PG_FUNCTION_ARGS)
{
char *lit = PG_GETARG_CSTRING(0);
int32 typmod = PG_GETARG_INT32(2);
half x[HALFVEC_MAX_DIM];
int dim = 0;
char *pt = lit;
HalfVector *result;
while (halfvec_isspace(*pt))
pt++;
if (*pt != '[')
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type halfvec: \"%s\"", lit),
errdetail("Vector contents must start with \"[\".")));
pt++;
while (halfvec_isspace(*pt))
pt++;
if (*pt == ']')
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("halfvec must have at least 1 dimension")));
for (;;)
{
float val;
char *stringEnd;
if (dim == HALFVEC_MAX_DIM)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("halfvec cannot have more than %d dimensions", HALFVEC_MAX_DIM)));
while (halfvec_isspace(*pt))
pt++;
/* Check for empty string like float4in */
if (*pt == '\0')
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type halfvec: \"%s\"", lit)));
errno = 0;
/* Postgres sets LC_NUMERIC to C on startup */
val = strtof(pt, &stringEnd);
if (stringEnd == pt)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type halfvec: \"%s\"", lit)));
x[dim] = Float4ToHalfUnchecked(val);
/* Check for range error like float4in */
if ((errno == ERANGE && isinf(val)) || (HalfIsInf(x[dim]) && !isinf(val)))
ereport(ERROR,
(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
errmsg("\"%s\" is out of range for type halfvec", pnstrdup(pt, stringEnd - pt))));
CheckElement(x[dim]);
dim++;
pt = stringEnd;
while (halfvec_isspace(*pt))
pt++;
if (*pt == ',')
pt++;
else if (*pt == ']')
{
pt++;
break;
}
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type halfvec: \"%s\"", lit)));
}
/* Only whitespace is allowed after the closing brace */
while (halfvec_isspace(*pt))
pt++;
if (*pt != '\0')
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for type halfvec: \"%s\"", lit),
errdetail("Junk after closing right brace.")));
CheckDim(dim);
CheckExpectedDim(typmod, dim);
result = InitHalfVector(dim);
for (int i = 0; i < dim; i++)
result->x[i] = x[i];
PG_RETURN_POINTER(result);
}
#define AppendChar(ptr, c) (*(ptr)++ = (c))
#define AppendFloat(ptr, f) ((ptr) += float_to_shortest_decimal_bufn((f), (ptr)))
/*
* Convert internal representation to textual representation
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_out);
Datum
halfvec_out(PG_FUNCTION_ARGS)
{
HalfVector *vector = PG_GETARG_HALFVEC_P(0);
int dim = vector->dim;
char *buf;
char *ptr;
/*
* Need:
*
* dim * (FLOAT_SHORTEST_DECIMAL_LEN - 1) bytes for
* float_to_shortest_decimal_bufn
*
* dim - 1 bytes for separator
*
* 3 bytes for [, ], and \0
*/
buf = (char *) palloc(FLOAT_SHORTEST_DECIMAL_LEN * dim + 2);
ptr = buf;
AppendChar(ptr, '[');
for (int i = 0; i < dim; i++)
{
if (i > 0)
AppendChar(ptr, ',');
/*
* Use shortest decimal representation of single-precision float for
* simplicity
*/
AppendFloat(ptr, HalfToFloat4(vector->x[i]));
}
AppendChar(ptr, ']');
*ptr = '\0';
PG_FREE_IF_COPY(vector, 0);
PG_RETURN_CSTRING(buf);
}
/*
* Convert type modifier
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_typmod_in);
Datum
halfvec_typmod_in(PG_FUNCTION_ARGS)
{
ArrayType *ta = PG_GETARG_ARRAYTYPE_P(0);
int32 *tl;
int n;
tl = ArrayGetIntegerTypmods(ta, &n);
if (n != 1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid type modifier")));
if (*tl < 1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("dimensions for type halfvec must be at least 1")));
if (*tl > HALFVEC_MAX_DIM)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("dimensions for type halfvec cannot exceed %d", HALFVEC_MAX_DIM)));
PG_RETURN_INT32(*tl);
}
/*
* Convert external binary representation to internal representation
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_recv);
Datum
halfvec_recv(PG_FUNCTION_ARGS)
{
StringInfo buf = (StringInfo) PG_GETARG_POINTER(0);
int32 typmod = PG_GETARG_INT32(2);
HalfVector *result;
int16 dim;
int16 unused;
dim = pq_getmsgint(buf, sizeof(int16));
unused = pq_getmsgint(buf, sizeof(int16));
CheckDim(dim);
CheckExpectedDim(typmod, dim);
if (unused != 0)
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("expected unused to be 0, not %d", unused)));
result = InitHalfVector(dim);
for (int i = 0; i < dim; i++)
{
result->x[i] = pq_getmsghalf(buf);
CheckElement(result->x[i]);
}
PG_RETURN_POINTER(result);
}
/*
* Convert internal representation to the external binary representation
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_send);
Datum
halfvec_send(PG_FUNCTION_ARGS)
{
HalfVector *vec = PG_GETARG_HALFVEC_P(0);
StringInfoData buf;
pq_begintypsend(&buf);
pq_sendint(&buf, vec->dim, sizeof(int16));
pq_sendint(&buf, vec->unused, sizeof(int16));
for (int i = 0; i < vec->dim; i++)
pq_sendhalf(&buf, vec->x[i]);
PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}
/*
* Convert half vector to half vector
* This is needed to check the type modifier
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec);
Datum
halfvec(PG_FUNCTION_ARGS)
{
HalfVector *vec = PG_GETARG_HALFVEC_P(0);
int32 typmod = PG_GETARG_INT32(1);
CheckExpectedDim(typmod, vec->dim);
PG_RETURN_POINTER(vec);
}
/*
* Convert array to half vector
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(array_to_halfvec);
Datum
array_to_halfvec(PG_FUNCTION_ARGS)
{
ArrayType *array = PG_GETARG_ARRAYTYPE_P(0);
int32 typmod = PG_GETARG_INT32(1);
HalfVector *result;
int16 typlen;
bool typbyval;
char typalign;
Datum *elemsp;
int nelemsp;
if (ARR_NDIM(array) > 1)
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("array must be 1-D")));
if (ARR_HASNULL(array) && array_contains_nulls(array))
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("array must not contain nulls")));
get_typlenbyvalalign(ARR_ELEMTYPE(array), &typlen, &typbyval, &typalign);
deconstruct_array(array, ARR_ELEMTYPE(array), typlen, typbyval, typalign, &elemsp, NULL, &nelemsp);
CheckDim(nelemsp);
CheckExpectedDim(typmod, nelemsp);
result = InitHalfVector(nelemsp);
if (ARR_ELEMTYPE(array) == INT4OID)
{
for (int i = 0; i < nelemsp; i++)
result->x[i] = Float4ToHalf(DatumGetInt32(elemsp[i]));
}
else if (ARR_ELEMTYPE(array) == FLOAT8OID)
{
for (int i = 0; i < nelemsp; i++)
result->x[i] = Float4ToHalf(DatumGetFloat8(elemsp[i]));
}
else if (ARR_ELEMTYPE(array) == FLOAT4OID)
{
for (int i = 0; i < nelemsp; i++)
result->x[i] = Float4ToHalf(DatumGetFloat4(elemsp[i]));
}
else if (ARR_ELEMTYPE(array) == NUMERICOID)
{
for (int i = 0; i < nelemsp; i++)
result->x[i] = Float4ToHalf(DatumGetFloat4(DirectFunctionCall1(numeric_float4, elemsp[i])));
}
else
{
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("unsupported array type")));
}
/*
* Free allocation from deconstruct_array. Do not free individual elements
* when pass-by-reference since they point to original array.
*/
pfree(elemsp);
/* Check elements */
for (int i = 0; i < result->dim; i++)
CheckElement(result->x[i]);
PG_RETURN_POINTER(result);
}
/*
* Convert half vector to float4[]
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_to_float4);
Datum
halfvec_to_float4(PG_FUNCTION_ARGS)
{
HalfVector *vec = PG_GETARG_HALFVEC_P(0);
Datum *datums;
ArrayType *result;
datums = (Datum *) palloc(sizeof(Datum) * vec->dim);
for (int i = 0; i < vec->dim; i++)
datums[i] = Float4GetDatum(HalfToFloat4(vec->x[i]));
/* Use TYPALIGN_INT for float4 */
result = construct_array(datums, vec->dim, FLOAT4OID, sizeof(float4), true, TYPALIGN_INT);
pfree(datums);
PG_RETURN_POINTER(result);
}
/*
* Convert vector to half vec
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(vector_to_halfvec);
Datum
vector_to_halfvec(PG_FUNCTION_ARGS)
{
Vector *vec = PG_GETARG_VECTOR_P(0);
int32 typmod = PG_GETARG_INT32(1);
HalfVector *result;
CheckDim(vec->dim);
CheckExpectedDim(typmod, vec->dim);
result = InitHalfVector(vec->dim);
for (int i = 0; i < vec->dim; i++)
result->x[i] = Float4ToHalf(vec->x[i]);
PG_RETURN_POINTER(result);
}
/*
* Get the L2 distance between half vectors
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_l2_distance);
Datum
halfvec_l2_distance(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
HalfVector *b = PG_GETARG_HALFVEC_P(1);
CheckDims(a, b);
PG_RETURN_FLOAT8(sqrt((double) HalfvecL2SquaredDistance(a->dim, a->x, b->x)));
}
/*
* Get the L2 squared distance between half vectors
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_l2_squared_distance);
Datum
halfvec_l2_squared_distance(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
HalfVector *b = PG_GETARG_HALFVEC_P(1);
CheckDims(a, b);
PG_RETURN_FLOAT8((double) HalfvecL2SquaredDistance(a->dim, a->x, b->x));
}
/*
* Get the inner product of two half vectors
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_inner_product);
Datum
halfvec_inner_product(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
HalfVector *b = PG_GETARG_HALFVEC_P(1);
CheckDims(a, b);
PG_RETURN_FLOAT8((double) HalfvecInnerProduct(a->dim, a->x, b->x));
}
/*
* Get the negative inner product of two half vectors
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_negative_inner_product);
Datum
halfvec_negative_inner_product(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
HalfVector *b = PG_GETARG_HALFVEC_P(1);
CheckDims(a, b);
PG_RETURN_FLOAT8((double) -HalfvecInnerProduct(a->dim, a->x, b->x));
}
/*
* Get the cosine distance between two half vectors
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_cosine_distance);
Datum
halfvec_cosine_distance(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
HalfVector *b = PG_GETARG_HALFVEC_P(1);
double similarity;
CheckDims(a, b);
similarity = HalfvecCosineSimilarity(a->dim, a->x, b->x);
#ifdef _MSC_VER
/* /fp:fast may not propagate NaN */
if (isnan(similarity))
PG_RETURN_FLOAT8(NAN);
#endif
/* Keep in range */
if (similarity > 1)
similarity = 1;
else if (similarity < -1)
similarity = -1;
PG_RETURN_FLOAT8(1 - similarity);
}
/*
* Get the distance for spherical k-means
* Currently uses angular distance since needs to satisfy triangle inequality
* Assumes inputs are unit vectors (skips norm)
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_spherical_distance);
Datum
halfvec_spherical_distance(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
HalfVector *b = PG_GETARG_HALFVEC_P(1);
double distance;
CheckDims(a, b);
distance = (double) HalfvecInnerProduct(a->dim, a->x, b->x);
/* Prevent NaN with acos with loss of precision */
if (distance > 1)
distance = 1;
else if (distance < -1)
distance = -1;
PG_RETURN_FLOAT8(acos(distance) / M_PI);
}
/*
* Get the L1 distance between two half vectors
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_l1_distance);
Datum
halfvec_l1_distance(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
HalfVector *b = PG_GETARG_HALFVEC_P(1);
CheckDims(a, b);
PG_RETURN_FLOAT8((double) HalfvecL1Distance(a->dim, a->x, b->x));
}
/*
* Get the dimensions of a half vector
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_vector_dims);
Datum
halfvec_vector_dims(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
PG_RETURN_INT32(a->dim);
}
/*
* Get the L2 norm of a half vector
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_l2_norm);
Datum
halfvec_l2_norm(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
half *ax = a->x;
double norm = 0.0;
/* Auto-vectorized */
for (int i = 0; i < a->dim; i++)
{
double axi = (double) HalfToFloat4(ax[i]);
norm += axi * axi;
}
PG_RETURN_FLOAT8(sqrt(norm));
}
/*
* Normalize a half vector with the L2 norm
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_l2_normalize);
Datum
halfvec_l2_normalize(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
half *ax = a->x;
double norm = 0;
HalfVector *result;
half *rx;
result = InitHalfVector(a->dim);
rx = result->x;
/* Auto-vectorized */
for (int i = 0; i < a->dim; i++)
norm += (double) HalfToFloat4(ax[i]) * (double) HalfToFloat4(ax[i]);
norm = sqrt(norm);
/* Return zero vector for zero norm */
if (norm > 0)
{
for (int i = 0; i < a->dim; i++)
rx[i] = Float4ToHalfUnchecked(HalfToFloat4(ax[i]) / norm);
/* Check for overflow */
for (int i = 0; i < a->dim; i++)
{
if (HalfIsInf(rx[i]))
float_overflow_error();
}
}
PG_RETURN_POINTER(result);
}
/*
* Add half vectors
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_add);
Datum
halfvec_add(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
HalfVector *b = PG_GETARG_HALFVEC_P(1);
half *ax = a->x;
half *bx = b->x;
HalfVector *result;
half *rx;
CheckDims(a, b);
result = InitHalfVector(a->dim);
rx = result->x;
/* Auto-vectorized */
for (int i = 0, imax = a->dim; i < imax; i++)
{
#ifdef FLT16_SUPPORT
rx[i] = ax[i] + bx[i];
#else
rx[i] = Float4ToHalfUnchecked(HalfToFloat4(ax[i]) + HalfToFloat4(bx[i]));
#endif
}
/* Check for overflow */
for (int i = 0, imax = a->dim; i < imax; i++)
{
if (HalfIsInf(rx[i]))
float_overflow_error();
}
PG_RETURN_POINTER(result);
}
/*
* Subtract half vectors
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_sub);
Datum
halfvec_sub(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
HalfVector *b = PG_GETARG_HALFVEC_P(1);
half *ax = a->x;
half *bx = b->x;
HalfVector *result;
half *rx;
CheckDims(a, b);
result = InitHalfVector(a->dim);
rx = result->x;
/* Auto-vectorized */
for (int i = 0, imax = a->dim; i < imax; i++)
{
#ifdef FLT16_SUPPORT
rx[i] = ax[i] - bx[i];
#else
rx[i] = Float4ToHalfUnchecked(HalfToFloat4(ax[i]) - HalfToFloat4(bx[i]));
#endif
}
/* Check for overflow */
for (int i = 0, imax = a->dim; i < imax; i++)
{
if (HalfIsInf(rx[i]))
float_overflow_error();
}
PG_RETURN_POINTER(result);
}
/*
* Multiply half vectors
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_mul);
Datum
halfvec_mul(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
HalfVector *b = PG_GETARG_HALFVEC_P(1);
half *ax = a->x;
half *bx = b->x;
HalfVector *result;
half *rx;
CheckDims(a, b);
result = InitHalfVector(a->dim);
rx = result->x;
/* Auto-vectorized */
for (int i = 0, imax = a->dim; i < imax; i++)
{
#ifdef FLT16_SUPPORT
rx[i] = ax[i] * bx[i];
#else
rx[i] = Float4ToHalfUnchecked(HalfToFloat4(ax[i]) * HalfToFloat4(bx[i]));
#endif
}
/* Check for overflow and underflow */
for (int i = 0, imax = a->dim; i < imax; i++)
{
if (HalfIsInf(rx[i]))
float_overflow_error();
if (HalfIsZero(rx[i]) && !(HalfIsZero(ax[i]) || HalfIsZero(bx[i])))
float_underflow_error();
}
PG_RETURN_POINTER(result);
}
/*
* Concatenate half vectors
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_concat);
Datum
halfvec_concat(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
HalfVector *b = PG_GETARG_HALFVEC_P(1);
HalfVector *result;
int dim = a->dim + b->dim;
CheckDim(dim);
result = InitHalfVector(dim);
for (int i = 0; i < a->dim; i++)
result->x[i] = a->x[i];
for (int i = 0; i < b->dim; i++)
result->x[i + a->dim] = b->x[i];
PG_RETURN_POINTER(result);
}
/*
* Quantize a half vector
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_binary_quantize);
Datum
halfvec_binary_quantize(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
half *ax = a->x;
VarBit *result = InitBitVector(a->dim);
unsigned char *rx = VARBITS(result);
for (int i = 0; i < a->dim; i++)
rx[i / 8] |= (HalfToFloat4(ax[i]) > 0) << (7 - (i % 8));
PG_RETURN_VARBIT_P(result);
}
/*
* Get a subvector
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_subvector);
Datum
halfvec_subvector(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
int32 start = PG_GETARG_INT32(1);
int32 count = PG_GETARG_INT32(2);
int32 end;
half *ax = a->x;
HalfVector *result;
int32 dim;
if (count < 1)
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("halfvec must have at least 1 dimension")));
/*
* Check if (start + count > a->dim), avoiding integer overflow. a->dim
* and count are both positive, so a->dim - count won't overflow.
*/
if (start > a->dim - count)
end = a->dim + 1;
else
end = start + count;
/* Indexing starts at 1, like substring */
if (start < 1)
start = 1;
else if (start > a->dim)
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("halfvec must have at least 1 dimension")));
dim = end - start;
CheckDim(dim);
result = InitHalfVector(dim);
for (int i = 0; i < dim; i++)
result->x[i] = ax[start - 1 + i];
PG_RETURN_POINTER(result);
}
/*
* Internal helper to compare half vectors
*/
static int
halfvec_cmp_internal(HalfVector * a, HalfVector * b)
{
int dim = Min(a->dim, b->dim);
/* Check values before dimensions to be consistent with Postgres arrays */
for (int i = 0; i < dim; i++)
{
if (HalfToFloat4(a->x[i]) < HalfToFloat4(b->x[i]))
return -1;
if (HalfToFloat4(a->x[i]) > HalfToFloat4(b->x[i]))
return 1;
}
if (a->dim < b->dim)
return -1;
if (a->dim > b->dim)
return 1;
return 0;
}
/*
* Less than
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_lt);
Datum
halfvec_lt(PG_FUNCTION_ARGS)
{
HalfVector *a = PG_GETARG_HALFVEC_P(0);
HalfVector *b = PG_GETARG_HALFVEC_P(1);
PG_RETURN_BOOL(halfvec_cmp_internal(a, b) < 0);
}
/*
* Less than or equal
*/
FUNCTION_PREFIX PG_FUNCTION_INFO_V1(halfvec_le);
Datum
halfvec_le(PG_FUNCTION_ARGS)