_s (e.g. ‘netflix_s’)
The left and right singular vector tables are of the format:
| row_id |
INTEGER. The ID corresponding to each eigenvalue (in decreasing order). |
| row_vec |
FLOAT8[]. Singular vector elements for this row_id. Each array is of size k. |
The singular values table is in sparse table format, since only the diagonal
elements of the matrix are non-zero:
| row_id |
INTEGER. \e i for \e ith eigenvalue. |
| col_id |
INTEGER. \e i for \e ith eigenvalue (same as row_id). |
| value |
FLOAT8. Eigenvalue. |
All \c row_id and \c col_id in the above tables start from 1.
The result summary table has the following columns:
| rows_used |
INTEGER. Number of rows used for SVD calculation. |
| exec_time |
FLOAT8. Total time for executing SVD. |
| iter |
INTEGER. Total number of iterations run. |
| recon_error |
FLOAT8. Total quality score (i.e. approximation quality) for this set of orthonormal basis. |
| relative_recon_error |
FLOAT8. Relative quality score. |
In the result summary table, the reconstruction error is computed as \f$
\sqrt{mean((X - USV^T)_{ij}^2)} \f$, where the average is over all elements of
the matrices. The relative reconstruction error is then computed as ratio of the
reconstruction error and \f$ \sqrt{mean(X_{ij}^2)} \f$.
@anchor examples
@examp
-# View online help for the SVD function.
SELECT madlib.svd();
-# Create an input dataset (dense matrix).
DROP TABLE IF EXISTS mat, mat_sparse, svd_summary_table, svd_u, svd_v, svd_s;
CREATE TABLE mat (
row_id integer,
row_vec double precision[]
);
INSERT INTO mat VALUES
(1,'{396,840,353,446,318,886,15,584,159,383}'),
(2,'{691,58,899,163,159,533,604,582,269,390}'),
(3,'{293,742,298,75,404,857,941,662,846,2}'),
(4,'{462,532,787,265,982,306,600,608,212,885}'),
(5,'{304,151,337,387,643,753,603,531,459,652}'),
(6,'{327,946,368,943,7,516,272,24,591,204}'),
(7,'{877,59,260,302,891,498,710,286,864,675}'),
(8,'{458,959,774,376,228,354,300,669,718,565}'),
(9,'{824,390,818,844,180,943,424,520,65,913}'),
(10,'{882,761,398,688,761,405,125,484,222,873}'),
(11,'{528,1,860,18,814,242,314,965,935,809}'),
(12,'{492,220,576,289,321,261,173,1,44,241}'),
(13,'{415,701,221,503,67,393,479,218,219,916}'),
(14,'{350,192,211,633,53,783,30,444,176,932}'),
(15,'{909,472,871,695,930,455,398,893,693,838}'),
(16,'{739,651,678,577,273,935,661,47,373,618}');
-# Run SVD function for a dense matrix.
SELECT madlib.svd( 'mat', -- Input table
'svd', -- Output table prefix
'row_id', -- Column name with row index
10, -- Number of singular values to compute
NULL, -- Use default number of iterations
'svd_summary_table' -- Result summary table
);
-# Print out the singular values and the summary table. For the singular values:
SELECT * FROM svd_s ORDER BY row_id;
Result:
row_id | col_id | value
--------+--------+------------------
1 | 1 | 6475.67225281804
2 | 2 | 1875.18065580415
3 | 3 | 1483.25228429636
4 | 4 | 1159.72262897427
5 | 5 | 1033.86092570574
6 | 6 | 948.437358703966
7 | 7 | 795.379572772455
8 | 8 | 709.086240684469
9 | 9 | 462.473775959371
10 | 10 | 365.875217945698
10 | 10 |
(11 rows)
For the summary table:
SELECT * FROM svd_summary_table;
Result:
rows_used | exec_time (ms) | iter | recon_error | relative_recon_error
-----------+----------------+------+-------------------+----------------------
16 | 1332.47 | 10 | 4.36920148766e-13 | 7.63134130332e-16
(1 row)
-# Create a sparse matrix by running the \ref matrix_sparsify() utility function on the dense matrix.
SELECT madlib.matrix_sparsify('mat',
'row=row_id, val=row_vec',
'mat_sparse',
'row=row_id, col=col_id, val=value');
-# Run the SVD function for a sparse matrix.
SELECT madlib.svd_sparse( 'mat_sparse', -- Input table
'svd', -- Output table prefix
'row_id', -- Column name with row index
'col_id', -- Column name with column index
'value', -- Matrix cell value
16, -- Number of rows in matrix
10, -- Number of columns in matrix
10 -- Number of singular values to compute
);
-# Run the SVD function for a very sparse matrix.
SELECT madlib.svd_sparse_native ( 'mat_sparse', -- Input table
'svd', -- Output table prefix
'row_id', -- Column name with row index
'col_id', -- Column name with column index
'value', -- Matrix cell value
16, -- Number of rows in matrix
10, -- Number of columns in matrix
10 -- Number of singular values to compute
);
@anchor background
@par Technical Background
In linear algebra, the singular value decomposition (SVD) is a factorization of
a real or complex matrix, with many useful applications in signal processing and
statistics.
Let \f$A\f$ be a \f$m \times n\f$ matrix, where \f$m \ge n\f$. Then \f$A\f$ can be
decomposed as follows:
\f[
A = U \Sigma V^T,
\f]
where \f$U\f$ is a \f$m \times n\f$ orthonormal matrix,
\f$\Sigma\f$ is a \f$n \times n\f$ diagonal matrix, and \f$V\f$ is an
\f$n \times n\f$ orthonormal matrix. The diagonal elements of \f$\Sigma\f$ are
called the singular values.
It is possible to formulate the problem of computing the singular triplets
(\f$\sigma_i, u_i, v_i\f$) of \f$A\f$ as an eigenvalue problem involving a Hermitian
matrix related to \f$A\f$. There are two possible ways of achieving this:
- With the cross product matrix, \f$A^TA\f$ and \f$AA^T\f$
- With the cyclic matrix
\f[
H(A) =
\begin{bmatrix}
0 & A\\
A^* & 0
\end{bmatrix}
\f]
The singular values are the nonnegative square roots of the eigenvalues of the
cross product matrix. This approach may imply a severe loss of accuracy in the
smallest singular values. The cyclic matrix approach is an alternative that
avoids this problem, but at the expense of significantly increasing the cost of
the computation.
Computing the cross product matrix explicitly is not recommended, especially in
the case of sparse A. Bidiagonalization was proposed by Golub and Kahan
[citation?] as a way of tridiagonalizing the cross product matrix without
forming it explicitly.
Consider the following decomposition
\f[ A = P B Q^T, \f]
where \f$P\f$ and \f$Q\f$ are unitary matrices and \f$B\f$ is an \f$m \times n\f$
upper bidiagonal matrix. Then the tridiagonal matrix \f$B*B\f$ is unitarily
similar to \f$A*A\f$. Additionally, specific methods exist that compute the
singular values of \f$B\f$ without forming \f$B*B\f$. Therefore, after computing the SVD of B,
\f[
B = X\Sigma Y^T,
\f]
it only remains to compute the SVD of the original matrix with \f$U = PX\f$ and \f$V = QY\f$.
*/
-- -----------------------------------------------------------------------
-- Main function for SVD (Dense format)
-- -----------------------------------------------------------------------
/*
@brief Compute an singular value decomposition for a dense matrix stored in a
database table
*/
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.svd(
source_table TEXT, -- Source table name (dense array-format matrix)
output_table_prefix TEXT, -- Prefix for output tables
row_id TEXT, -- ID for each row
k INTEGER, -- Number of singular vectors to compute
n_iterations INTEGER, -- Iteration number of Lanczos
result_summary_table TEXT -- Table name to store result summary
)
RETURNS VOID AS $$
PythonFunctionBodyOnly(`linalg', `svd')
with AOControl(False):
return svd.svd(schema_madlib, source_table, output_table_prefix,
row_id, k, n_iterations, result_summary_table)
$$ LANGUAGE plpythonu
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');
-- -----------------------------------------------------------------------
-- Main function for SVD (Block format)
-- Each row in the input table is a triple:
-- -----------------------------------------------------------------------
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.svd_block(
source_table TEXT, -- Source table name (dense block-format matrix)
output_table_prefix TEXT, -- Prefix for output tables
k INTEGER, -- Number of singular vectors to compute
n_iterations INTEGER, -- Iteration number of Lanczos
result_summary_table TEXT -- Table name to store result summary
)
RETURNS VOID AS $$
PythonFunctionBodyOnly(`linalg', `svd')
with AOControl(False):
return svd.svd_block(schema_madlib, source_table, output_table_prefix, k,
n_iterations, result_summary_table)
$$ LANGUAGE plpythonu
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.svd_block(
source_table TEXT, -- Source table name (dense block-format matrix)
output_table_prefix TEXT, -- Prefix for output tables
k INTEGER, -- Number of singular vectors to compute
n_iterations INTEGER -- Iteration number of Lanczos
)
RETURNS VOID AS $$
SELECT MADLIB_SCHEMA.svd_block($1, $2, $3, $4, NULL)
$$ LANGUAGE SQL
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.svd_block(
source_table TEXT, -- Source table name (dense block-format matrix)
output_table_prefix TEXT, -- Prefix for output tables
k INTEGER -- Number of singular vectors to compute
)
RETURNS VOID AS $$
SELECT MADLIB_SCHEMA.svd_block($1, $2, $3, NULL, NULL)
$$ LANGUAGE SQL
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');
-- -----------------------------------------------------------------------
-- Main Function for SVD (sparse format)
-- -----------------------------------------------------------------------
/*
@brief Compute an singular value decomposition for a sparse matrix stored in a
database table
('input_table', 'output_table_prefix', ’row_id', ’col_id', 'value',
row_dim, col_dim, k, 'result_summary_table')
*/
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.svd_sparse(
source_table TEXT, -- Source table name (dense matrix)
output_table_prefix TEXT, -- Prefix for output tables
row_id TEXT, -- Name of ‘row_id’ column in sparse matrix representation
col_id TEXT, -- Name of 'col_id' column in sparse matrix representation
val_id TEXT, -- Name of 'val_id' column in sparse matrix representation
row_dim INTEGER, -- row dimension of sparse matrix
col_dim INTEGER, -- col dimension of sparse matrix
k INTEGER, -- Number of singular vectors with dominant singular values, sorted decreasingly
n_iterations INTEGER, -- Iteration number of Lanczos
result_summary_table TEXT -- Table name to store result summary
)
RETURNS VOID AS $$
PythonFunctionBodyOnly(`linalg', `svd')
with AOControl(False):
return svd.svd_sparse(schema_madlib, source_table, output_table_prefix,
row_id, col_id, val_id, row_dim, col_dim, k,
n_iterations, result_summary_table)
$$ LANGUAGE plpythonu
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.svd_sparse_native(
source_table TEXT, -- Source table name (dense matrix)
output_table_prefix TEXT, -- Prefix for output tables
row_id TEXT, -- Name of ‘row_id’ column in sparse matrix representation
col_id TEXT, -- Name of 'col_id' column in sparse matrix representation
val_id TEXT, -- Name of 'val_id' column in sparse matrix representation
row_dim INTEGER, -- row dimension of sparse matrix
col_dim INTEGER, -- col dimension of sparse matrix
k INTEGER, -- Number of singular vectors with dominant singular values,
-- sorted decreasingly
n_iterations INTEGER, -- Iteration number of Lanczos
result_summary_table TEXT -- Table name to store result summary
)
RETURNS VOID AS $$
PythonFunctionBodyOnly(`linalg', `svd')
with AOControl(False):
return svd.svd_sparse_native(schema_madlib, source_table,
output_table_prefix, row_id, col_id,
val_id, row_dim, col_dim, k, n_iterations,
result_summary_table)
$$ LANGUAGE plpythonu
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');
-- -----------------------------------------------------------------------
-- Overloaded functions for optional parameters
-- -----------------------------------------------------------------------
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.svd(
source_table TEXT, -- Source table name (dense matrix)
output_table_prefix TEXT, -- Prefix for output tables
row_id TEXT, -- ID for each row
k INTEGER -- Number of singular vectors to compute
)
RETURNS VOID AS $$
SELECT MADLIB_SCHEMA.svd($1, $2, $3, $4, NULL, NULL)
$$ LANGUAGE SQL
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.svd_sparse(
source_table TEXT, -- Source table name (dense matrix)
output_table_prefix TEXT, -- Prefix for output tables
row_id TEXT, -- Name of ‘row_id’ column in sparse matrix representation
col_id TEXT, -- Name of 'col_id' column in sparse matrix representation
val_id TEXT, -- Name of 'val_id' column in sparse matrix representation
row_dim INTEGER, -- row dimension of sparse matrix
col_dim INTEGER, -- col dimension of sparse matrix
k INTEGER -- Number of singular vectors with dominant singular values, sorted decreasingly
)
RETURNS VOID AS $$
SELECT MADLIB_SCHEMA.svd_sparse($1, $2, $3, $4, $5, $6, $7, $8, NULL, NULL)
$$ LANGUAGE SQL
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.svd(
source_table TEXT, -- Source table name (dense matrix)
output_table_prefix TEXT, -- Prefix for output tables
row_id TEXT, -- ID for each row
k INTEGER, -- Number of singular vectors to compute
n_iterations INTEGER -- Iteration number of Lanczos
)
RETURNS VOID AS $$
SELECT MADLIB_SCHEMA.svd($1, $2, $3, $4, $5, NULL)
$$ LANGUAGE SQL
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.svd_sparse(
source_table TEXT, -- Source table name (dense matrix)
output_table_prefix TEXT, -- Prefix for output tables
row_id TEXT, -- Name of ‘row_id’ column in sparse matrix representation
col_id TEXT, -- Name of 'col_id' column in sparse matrix representation
val_id TEXT, -- Name of 'val_id' column in sparse matrix representation
row_dim INTEGER, -- row dimension of sparse matrix
col_dim INTEGER, -- col dimension of sparse matrix
k INTEGER, -- Number of singular vectors with dominant singular values, sorted decreasingly
n_iterations INTEGER -- Iteration number of Lanczos
)
RETURNS VOID AS $$
SELECT MADLIB_SCHEMA.svd_sparse($1, $2, $3, $4, $5, $6, $7, $8, $9, NULL)
$$ LANGUAGE SQL
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.svd_sparse_native(
source_table TEXT, -- Source table name (dense matrix)
output_table_prefix TEXT, -- Prefix for output tables
row_id TEXT, -- Name of ‘row_id’ column in sparse matrix representation
col_id TEXT, -- Name of 'col_id' column in sparse matrix representation
val_id TEXT, -- Name of 'val_id' column in sparse matrix representation
row_dim INTEGER, -- row dimension of sparse matrix
col_dim INTEGER, -- col dimension of sparse matrix
k INTEGER -- Number of singular vectors with dominant singular
-- values, sorted decreasingly
)
RETURNS VOID AS $$
SELECT MADLIB_SCHEMA.svd_sparse_native($1, $2, $3, $4, $5, $6, $7, $8, NULL, NULL)
$$ LANGUAGE SQL
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.svd_sparse_native(
source_table TEXT, -- Source table name (dense matrix)
output_table_prefix TEXT, -- Prefix for output tables
row_id TEXT, -- Name of ‘row_id’ column in sparse matrix representation
col_id TEXT, -- Name of 'col_id' column in sparse matrix representation
val_id TEXT, -- Name of 'val_id' column in sparse matrix representation
row_dim INTEGER, -- row dimension of sparse matrix
col_dim INTEGER, -- col dimension of sparse matrix
k INTEGER, -- Number of singular vectors with dominant singular values, sorted decreasingly
n_iterations INTEGER -- Iteration number of Lanczos
)
RETURNS VOID AS $$
SELECT MADLIB_SCHEMA.svd_sparse_native($1, $2, $3, $4, $5, $6, $7, $8, $9, NULL)
$$ LANGUAGE SQL
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');;
---------------------------------------------------------------------
------------------------Internal Functions---------------------------
---------------------------------------------------------------------
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.__svd_unit_vector
(
dim INT -- Dimension of the vector
)
-- RETURNS MADLIB_SCHEMA.__svd_unit_vector_result
RETURNS DOUBLE PRECISION[]
AS 'MODULE_PATHNAME', 'svd_unit_vector'
LANGUAGE C STRICT
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
DROP TYPE IF EXISTS MADLIB_SCHEMA.__svd_lanczos_result CASCADE;
CREATE TYPE MADLIB_SCHEMA.__svd_lanczos_result AS
(
scalar FLOAT8, -- alpha/beta
vec FLOAT8[] -- pvec/qvec
);
---------------------------------------------------------------------
-------Common Aggregator for Computing Lanzcos P/Q Vectors-----------
---------------------------------------------------------------------
---------------------------------------------------------------------
---------------------For Array-Format Matrix-------------------------
---------------------------------------------------------------------
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.__svd_lanczos_sfunc
(
state FLOAT8[], -- A * q_j OR A_Trans * p_(j-1)
row_id INT, -- Matrix row id
row_array FLOAT8[], -- Matrix row array
vector FLOAT8[], -- q_j OR p_(j-1)
dimension INT -- row_dim OR col_dim
)
RETURNS FLOAT8[]
AS 'MODULE_PATHNAME', 'svd_lanczos_sfunc'
LANGUAGE C
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
---------------------------------------------------------------------
---------------------For Block-Format Matrix-------------------------
---------------------------------------------------------------------
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.__svd_block_lanczos_sfunc
(
state FLOAT8[], -- A * q_j OR A_Trans * p_(j-1)
row_id INT4, -- Matrix block row id
col_id INT4, -- Matrix block col id
block FLOAT8[], -- Matrix block
vector FLOAT8[], -- q_j OR p_(j-1)
dimension INT4 -- row_dim OR col_dim
)
RETURNS FLOAT8[]
AS 'MODULE_PATHNAME', 'svd_block_lanczos_sfunc'
LANGUAGE C
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
---------------------------------------------------------------------
---------------------For Sparse-Format Matrix-------------------------
---------------------------------------------------------------------
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.__svd_sparse_lanczos_sfunc
(
state FLOAT8[], -- A * q_j OR A_Trans * p_(j-1)
row_id INT4, -- row id
col_id INT4, -- col id
val FLOAT8, -- value
vector FLOAT8[], -- q_j OR p_(j-1)
dimension INT4 -- row_dim OR col_dim
)
RETURNS FLOAT8[]
AS 'MODULE_PATHNAME', 'svd_sparse_lanczos_sfunc'
LANGUAGE C
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.__svd_lanczos_prefunc
(
state1 FLOAT8[],
state2 FLOAT8[]
)
RETURNS FLOAT8[]
AS 'MODULE_PATHNAME', 'svd_lanczos_prefunc'
LANGUAGE C STRICT
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
---------------------------------------------------------------------
---------------------For Array-Format Matrix-------------------------
---------------------------------------------------------------------
DROP AGGREGATE IF EXISTS
MADLIB_SCHEMA.__svd_lanczos_agg
(
INT, -- Matrix row id
FLOAT8[], -- Matrix row array
FLOAT8[], -- q_j OR p_(j-1)
INT -- row_dim OR col_dim
);
CREATE AGGREGATE
MADLIB_SCHEMA.__svd_lanczos_agg
(
INT, -- Matrix row id
FLOAT8[], -- Matrix row array
FLOAT8[], -- q_j OR p_(j-1)
INT -- row_dim OR col_dim
)
(
stype = FLOAT8[],
sfunc = MADLIB_SCHEMA.__svd_lanczos_sfunc
m4_ifdef(
`__POSTGRESQL__', `',
`, prefunc = MADLIB_SCHEMA.__svd_lanczos_prefunc'
)
);
---------------------------------------------------------------------
---------------------For Block-Format Matrix-------------------------
---------------------------------------------------------------------
DROP AGGREGATE IF EXISTS
MADLIB_SCHEMA.__svd_block_lanczos_agg
(
INT4, -- Matrix block row id
INT4, -- Matrix block col id
FLOAT8[], -- Matrix block
FLOAT8[], -- q_j OR p_(j-1)
INT4 -- row_dim OR col_dim
);
CREATE AGGREGATE
MADLIB_SCHEMA.__svd_block_lanczos_agg
(
INT, -- Matrix block row id
INT4, -- Matrix block col id
FLOAT8[], -- Matrix row array
FLOAT8[], -- q_j OR p_(j-1)
INT -- row_dim OR col_dim
)
(
stype = FLOAT8[],
--Note that only the sfunc is different
sfunc = MADLIB_SCHEMA.__svd_block_lanczos_sfunc
m4_ifdef(
`__POSTGRESQL__', `',
`, prefunc = MADLIB_SCHEMA.__svd_lanczos_prefunc'
)
);
---------------------------------------------------------------------
---------------------For Sparse-Format Matrix-------------------------
---------------------------------------------------------------------
DROP AGGREGATE IF EXISTS
MADLIB_SCHEMA.__svd_sparse_lanczos_agg
(
INT4, -- Row ID
INT4, -- Column ID
FLOAT8, -- Value
FLOAT8[], -- q_j OR p_(j-1)
INT4 -- row_dim OR col_dim
);
CREATE AGGREGATE
MADLIB_SCHEMA.__svd_sparse_lanczos_agg
(
INT4, -- Row ID
INT4, -- Column ID
FLOAT8, -- Value
FLOAT8[], -- q_j OR p_(j-1)
INT4 -- row_dim OR col_dim
)
(
stype = FLOAT8[],
--Note that only the sfunc is different
sfunc = MADLIB_SCHEMA.__svd_sparse_lanczos_sfunc
m4_ifdef(
`__POSTGRESQL__', `',
`, prefunc = MADLIB_SCHEMA.__svd_lanczos_prefunc'
)
);
---------------------------------------------------------------------
--------Postproc Function for Computing Lanzcos P/V Vectors---------
---------------------------------------------------------------------
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.__svd_lanczos_pvec
(
vector FLOAT8[], -- Partial result from the aggregator
pvec FLOAT8[], -- Previous P vector
beta FLOAT8 -- Previous beta
)
RETURNS MADLIB_SCHEMA.__svd_lanczos_result
AS 'MODULE_PATHNAME', 'svd_lanczos_pvec'
LANGUAGE C
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.__svd_lanczos_qvec
(
vector FLOAT8[], -- Partial result from the aggregator
qvec FLOAT8[], -- Previous P vector
alpha FLOAT8 -- Previous beta
)
RETURNS FLOAT8[]
AS 'MODULE_PATHNAME', 'svd_lanczos_qvec'
LANGUAGE C
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
---------------------------------------------------------------------
-----------------Gram-Schmidt Orthogonilization----------------------
---------------------------------------------------------------------
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.__svd_gram_schmidt_orthogonalize_sfunc
(
state FLOAT8[],
vec_unorthogonalized FLOAT8[],
vec_orthogonalized FLOAT8[]
)
RETURNS FLOAT8[]
AS 'MODULE_PATHNAME', 'svd_gram_schmidt_orthogonalize_sfunc'
LANGUAGE C
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.__svd_gram_schmidt_orthogonalize_prefunc
(
state1 FLOAT8[],
state2 FLOAT8[]
)
RETURNS FLOAT8[]
AS 'MODULE_PATHNAME', 'svd_gram_schmidt_orthogonalize_prefunc'
LANGUAGE C STRICT
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
-- This function will also do the normalization
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.__svd_gram_schmidt_orthogonalize_ffunc
(
state FLOAT8[]
)
RETURNS MADLIB_SCHEMA.__svd_lanczos_result
AS 'MODULE_PATHNAME', 'svd_gram_schmidt_orthogonalize_ffunc'
LANGUAGE C STRICT
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
DROP AGGREGATE IF EXISTS
MADLIB_SCHEMA.__svd_gram_schmidt_orthogonalize_agg
(
FLOAT8[], -- Unorthogonalized vector
FLOAT8[] -- Orthogonalized vector
);
CREATE AGGREGATE
MADLIB_SCHEMA.__svd_gram_schmidt_orthogonalize_agg
(
FLOAT8[], -- Unorthogonalized vector
FLOAT8[] -- Orthogonalized vector
)
(
stype = FLOAT8[],
sfunc = MADLIB_SCHEMA.__svd_gram_schmidt_orthogonalize_sfunc,
finalfunc = MADLIB_SCHEMA.__svd_gram_schmidt_orthogonalize_ffunc
m4_ifdef(
`__POSTGRESQL__', `',
`, prefunc = MADLIB_SCHEMA.__svd_gram_schmidt_orthogonalize_prefunc'
)
);
---------------------------------------------------------------------
--------------------Lanczos Bidiagonalization------------------------
---------------------------------------------------------------------
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.__svd_lanczos_bidiagonalize
(
source_table TEXT,
output_table_prefix TEXT,
n_iterations INT,
k INT,
is_block BOOLEAN
)
RETURNS VOID AS $$
PythonFunctionBodyOnly(`linalg', `svd')
with AOControl(False):
return svd.lanczos_bidiagonalize(schema_madlib, source_table,
output_table_prefix, n_iterations, k, is_block)
$$ LANGUAGE plpythonu
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');
CREATE OR REPLACE FUNCTION
MADLIB_SCHEMA.__svd_lanczos_bidiagonalize_sparse
(
source_table TEXT,
row_id TEXT,
col_id TEXT,
val TEXT,
output_table_prefix TEXT,
n_iterations INT,
k INT
)
RETURNS VOID AS $$
PythonFunctionBodyOnly(`linalg', `svd')
with AOControl(False):
return svd.lanczos_bidiagonalize_sparse(schema_madlib, source_table,
row_id, col_id, val,
output_table_prefix,
n_iterations, k)
$$ LANGUAGE plpythonu
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');
---------------------------------------------------------------------
-------------------- SVD of Bidiagonal matrix ------------------------
---------------------------------------------------------------------
DROP TYPE IF EXISTS MADLIB_SCHEMA.__svd_bidiagonal_matrix_result CASCADE;
CREATE TYPE MADLIB_SCHEMA.__svd_bidiagonal_matrix_result AS
(
left_matrix FLOAT8[][],
right_matrix FLOAT8[][],
singular_values FLOAT8[]
);
------------------------------------------------------------------------------
--The bidiagonal matrix is represented as a triple:
--where:
-- row_ids is an array of integers representing row_ids of non-zero elements
-- col_ids is an array of integers representing col_ids of non-zero elements
-- vals is an array of doubles representing values of non-zero elements
--Note that we don't need the aggregator to convert the sparse bidiagonal
--matrix into a dense matrix
------------------------------------------------------------------------------
CREATE OR REPLACE FUNCTION MADLIB_SCHEMA.__svd_decompose_bidiag(
row_ids INT[],
col_ids INT[],
vals FLOAT8[]
)
RETURNS MADLIB_SCHEMA.__svd_bidiagonal_matrix_result
AS 'MODULE_PATHNAME', 'svd_decompose_bidiag'
LANGUAGE C STRICT
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
-----------------------------------------------------------------------
-- Special Vector-Matrix Multiplication Functions
-----------------------------------------------------------------------
/**
* Multiplication of a row vector with an in-memory matrix
* vector: 1 x l
* matrix: l x l
* k: Sub-matrix of the size l x k
*/
CREATE OR REPLACE FUNCTION MADLIB_SCHEMA.__svd_vec_mult_matrix(
vector FLOAT8[],
matrix FLOAT8[][],
k INT4
)
RETURNS FLOAT8[]
AS 'MODULE_PATHNAME', 'svd_vec_mult_matrix'
LANGUAGE C STRICT
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
DROP TYPE IF EXISTS MADLIB_SCHEMA.__svd_vec_mat_mult_result CASCADE;
CREATE TYPE MADLIB_SCHEMA.__svd_vec_mat_mult_result AS
(
row_id INT4,
row_vec FLOAT8[]
);
--Multiplication of a column vector with an in-memory matrix
--Return a set of m row vector of the size 1 * k
CREATE OR REPLACE FUNCTION MADLIB_SCHEMA.__svd_vec_trans_mult_matrix_internal(
vector FLOAT8[], -- m * l row vector
matrix FLOAT8[][], -- l * l in-memory matrix
col_id INT4, -- Column ID
k INT4 -- Specify the size of submatrix l * k
)
RETURNS SETOF MADLIB_SCHEMA.__svd_vec_mat_mult_result
AS 'MODULE_PATHNAME', 'svd_vec_trans_mult_matrix'
LANGUAGE C STRICT
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
--Multiplication of P/Q vectors with Left/Right Singular Matrix of B
CREATE OR REPLACE FUNCTION MADLIB_SCHEMA.__svd_vec_trans_mult_matrix(
vec_table TEXT, -- P/Q column vectors
mat_table TEXT, -- (svd_output).left_matrix/right_matrix
k INT4, -- Number of singular values
is_left BOOLEAN, -- Left matrix?
res_table TEXT -- Result
)
RETURNS VOID AS $$
PythonFunctionBodyOnly(`linalg', `svd')
with AOControl(False):
return svd.svd_vec_trans_mult_matrix(schema_madlib, vec_table,
mat_table, k, res_table, is_left)
$$ LANGUAGE plpythonu
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `MODIFIES SQL DATA', `');
-----------------------------------------------------------------------
-- Help functions
-----------------------------------------------------------------------
CREATE OR REPLACE FUNCTION MADLIB_SCHEMA.svd(
input_message TEXT
)
RETURNS TEXT AS $$
PythonFunctionBodyOnly(`linalg', `svd')
return svd.svd_help_message(schema_madlib, input_message)
$$ LANGUAGE plpythonu
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');
CREATE OR REPLACE FUNCTION MADLIB_SCHEMA.svd()
RETURNS TEXT AS $$
PythonFunctionBodyOnly(`linalg', `svd')
return svd.svd_help_message(schema_madlib, None)
$$ LANGUAGE plpythonu
m4_ifdef(`__HAS_FUNCTION_PROPERTIES__', `NO SQL', `');