Julia set: Difference between revisions
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=={{header|Transact-SQL}}==
This is a Transact-SQL version of SQL Server to generate Julia set. Export the final result to a .ppm file to view the image.
<syntaxhighlight lang="Transact-SQL">
-- Juila Set
-- SQL Server 2017 and above
SET NOCOUNT ON
GO
-- Plot area 800 X 600
DECLARE @width INT = 800
DECLARE @height INT = 600
DECLARE @r_min DECIMAL (10, 8) = -1.5;
DECLARE @r_max DECIMAL (10, 8) = 1.5;
DECLARE @i_min DECIMAL (10, 8) = -1;
DECLARE @i_max DECIMAL (10, 8) = 1;
DECLARE @zoom INT = 1,
@moveX INT = 0,
@moveY INT = 0;
DECLARE @iter INT = 255; -- Iteration
DROP TABLE IF EXISTS dbo.Numbers
DROP TABLE IF EXISTS dbo.julia_set;
CREATE TABLE dbo.Numbers (n INT);
-- Generate a number table of 1000 rows
;WITH N1(n) AS
(
SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1
), -- 10
N2(n) AS (SELECT 1 FROM N1 CROSS JOIN N1 AS b), -- 10*10
N3(n) AS (SELECT 1 FROM N1 CROSS JOIN N2) -- 10*100
INSERT INTO dbo.Numbers (n)
SELECT n = ROW_NUMBER() OVER (ORDER BY n)
FROM N3 ORDER BY n;
/*
-- If the version is SQL Server 2022 and above
INSERT INTO dbo.Numbers (n)
SELECT value FROM GENERATE_SERIES(0, 1000);
*/
CREATE TABLE dbo.julia_set
(
a INT,
b INT,
c_re DECIMAL (10, 8),
c_im DECIMAL (10, 8),
z_re DECIMAL (10, 8) DEFAULT 0,
z_im DECIMAL (10, 8) DEFAULT 0,
znew_re DECIMAL (10, 8) DEFAULT 0,
znew_im DECIMAL (10, 8) DEFAULT 0,
steps INT DEFAULT 0,
active BIT DEFAULT 1,
)
-- Store all the z_re, z_im with constant c_re, c_im corresponding to each point in the plot area
-- Generate 480,000 rows (800 X 600)
INSERT INTO dbo.julia_set (a, b, c_re, c_im, z_re, z_im, steps)
SELECT a.n as a, b.n as b
,-0.7 AS c_re
,0.27015 AS c_im
,@r_max * (a.n - @width / 2) / (0.5 * @zoom * @width) + @moveX AS z_re
,@i_max * (b.n - @height / 2) / (0.5 * @zoom * @height) + @moveY AS z_im
,@iter as steps
FROM
(
SELECT n - 1 as n FROM dbo.Numbers WHERE n <= @width
) as a
CROSS JOIN
(
SELECT n - 1 as n FROM dbo.Numbers WHERE n <= @height
) as b;
-- Iteration
WHILE (@iter > 1)
BEGIN
UPDATE dbo.julia_set
SET
znew_re = POWER(z_re,2)-POWER(z_im,2)+c_re,
znew_im = 2*z_re*z_im+c_im,
steps = steps-1
WHERE active=1;
UPDATE dbo.julia_set
SET
z_re=znew_re,
z_im=znew_im,
active= CASE
WHEN POWER(znew_re,2)+POWER(znew_im,2)>4 THEN 0
ELSE 1
END
WHERE active=1;
SET @iter = @iter - 1;
END
-- Generating PPM File
-- Save the below query results to a file with extension .ppm
-- NOTE : All the unwanted info like 'rows affected', 'completed time' etc. needs to be
-- removed from the file. Most of the image editing softwares and online viewers can display the .ppm file
SELECT 'P3' UNION ALL
SELECT CAST(@width AS VARCHAR(5)) + ' ' + CAST(@height AS VARCHAR(5)) UNION ALL
SELECT '255' UNION ALL
SELECT
STRING_AGG(CAST(CASE WHEN active = 1 THEN 0 ELSE 55 + steps % 200 END AS VARCHAR(MAX)) + ' ' -- R
+ CAST(CASE WHEN active = 1 THEN 0 ELSE 55+POWER(steps,3) % 200 END AS VARCHAR(MAX)) + ' ' -- G
+ CAST(CASE WHEN active = 1 THEN 0 ELSE 55+ POWER(steps,2) % 200 END AS VARCHAR(MAX)) -- B
, ' ') WITHIN GROUP (ORDER BY a, b)
FROM dbo.julia_set
GROUP BY a, b
</syntaxhighlight>
'''OUTPUT'''
[[File:Julia set transact sql.png|thumb|Julia set in Transact-SQL]]
=={{header|VBScript}}==
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