CHOOSE - choose operation

Implements the choose operation, which chooses between elements of A or B.

Usage

The CHOOSE stored procedure has the following syntax:

CHOOSE(expression,matrixAname,matrixBname,matrixCname)

Parameters

expression: An expression choosing between A and B matrix elements.; Type: NVARCHAR(ANY)
matrixAname: The name of input matrix A.; Type: NVARCHAR(ANY)
matrixBname: The name of input matrix B.; Type: NVARCHAR(ANY)
matrixCname: The name of input matrix C.; Type: NVARCHAR(ANY)

Returns

BOOLEAN TRUE, if successful.

Details

The procedure implements the choose operation, which chooses between elements of A or B depending on the expression. Matrices A and B must be the same shape. The output matrix C is given the same shape. Each element of C is either the corresponding element of A or B depending on the value of the expression. In the expression the current element of A can be referred to as "a.value" and the current element of B referred to as "b.value" as shown in the example. The user is responsible for ensuring the expression is well-formed. Matrix C must not exist prior to the operation. Warning: Use "coalesce" in the user-supplied expression for sparse matrices to work.

Examples

CALL nzm..shape('1,2,3,4,5,6,7,8,9',3,3,'AA');
CALL nzm..shape('1,15,5,7',3,3,'BB');
CALL nzm..choose('a.value > b.value','AA','BB','CC');
CALL nzm..print('AA');CALL nzm..print('BB');
CALL nzm..print('CC');
CALL nzm..delete_matrix('AA');
CALL nzm..delete_matrix('BB');
CALL nzm..delete_matrix('CC');

 SHAPE
-------
 t
(1 row)

 SHAPE
-------
 t
(1 row)

 CHOOSE
--------
 t
(1 row)

                  PRINT
------------------------------------------
 -- matrix: AA --
1, 2, 3
4, 5, 6
7, 8, 9
(1 row)

                  PRINT
--------------------------------------------
 -- matrix: BB --
1, 15, 5
7, 1, 15
5, 7, 1
(1 row)

                 PRINT
--------------------------------------------
 -- matrix: CC --
1, 15, 5
7, 5, 15
7, 8, 9
(1 row)

 DELETE_MATRIX
---------------
 t
(1 row)

 DELETE_MATRIX
---------------
 t
(1 row)

 DELETE_MATRIX
---------------
 t
(1 row)

CALL nzm..shape('1,2,3,4,5,6,7,8,9',3,3,'AA'); 
CALL nzm..shape('1,15,5,7',3,3,'BB');
CALL nzm..choose('(a.value * b.value) < (a.value + b.value)', 'AA', 'BB', 'CC');
CALL nzm..print('CC');
CALL nzm..delete_matrix('AA');
CALL nzm..delete_matrix('BB');
CALL nzm..delete_matrix('CC');

 SHAPE
-------
 t
(1 row)

 SHAPE
-------
 t
(1 row)

 CHOOSE
--------
 t
(1 row)

                    PRINT
--------------------------------------------
 -- matrix: CC --
1, 15, 5
7, 5, 15
5, 7, 9
(1 row)

 DELETE_MATRIX
---------------
 t
(1 row)

 DELETE_MATRIX
---------------
 t
(1 row)

 DELETE_MATRIX
---------------
 t
(1 row)

CALL nzm..shape('1,2,3,4,5,6,7,8,9',3,3,'AA'); 
CALL nzm..shape('1,15,5,7',3,3,'BB');
CALL nzm..choose('(a.value < b.value) and (a.value > (b.value -10))', 'AA', 'BB', 'CC');
CALL nzm..print('CC');
CALL nzm..delete_matrix('AA');
CALL nzm..delete_matrix('BB');
CALL nzm..delete_matrix('CC');

 SHAPE
-------
 t
(1 row)

 SHAPE
-------
 t
(1 row)

 CHOOSE
--------
 t
(1 row)

                    PRINT
-------------------------------------------
 -- matrix: CC --
1, 15, 3
4, 1, 6
5, 7, 1
(1 row)

 DELETE_MATRIX
---------------
 t
(1 row)

 DELETE_MATRIX
---------------
 t
(1 row)

 DELETE_MATRIX
---------------
 t
(1 row)