## gnuplot-info

 [Gnuplot-info] 3D function From: Zhong Ren - 2009-06-10 16:04:20 ```Hi, I have a 3D function f(x, y, z) in form of a data file of 4 columns x, y, z, and f. The distribution of the function value f is symmetrical around 0 following a normal distribution. What is the best way to represent this kind of data in Gnuplot? Is there any example I can reference? Some software uses 3D net to represent contour surfaces. Thanks for any suggestions. Zhong ```
 Re: [Gnuplot-info] 3D function From: Hans-Bernhard Bröker - 2009-06-10 20:34:47 ```Zhong Ren wrote: > Hi, > > I have a 3D function f(x, y, z) in form of a data file of 4 > columns x, y, z, and f. The distribution of the function > value f is symmetrical around 0 Symmetrical --- how? There are quite a number of symmetries a 3D field can have. ```
 Re: [Gnuplot-info] 3D function From: Zhong Ren - 2009-06-10 22:29:38 ```That means most of the function values are around 0, equal amount of them are greater than 0 and less than 0. Less and less are large positive, and the same amount of them are large negative. I said the "function values" are symmetrically distributed, not x, y, z. People use red and green nets in 3D space to represent positive and negative contour surfaces, respectively. Hope this clarifies a bit. Zhong ---- Original message ---- >Date: Wed, 10 Jun 2009 22:34:38 +0200 >From: Hans-Bernhard Bröker >Subject: Re: [Gnuplot-info] 3D function >To: renz@... >Cc: gnuplot-info@... > >Zhong Ren wrote: >> Hi, >> >> I have a 3D function f(x, y, z) in form of a data file of 4 >> columns x, y, z, and f. The distribution of the function >> value f is symmetrical around 0 > >Symmetrical --- how? There are quite a number of symmetries a 3D field >can have. > ```
 [Gnuplot-info] contour at base From: Zhong Ren - 2009-06-11 21:07:52 ```This is one of the demos: set contour base splot x**2*y**3, x**3*y**2 It draws two surfaces and contours both at base. Now, I would like to put the contours at different z-levels. Is there a way to specify them? I tried to use set xyplane at . Both contours went there. How to separate them at different levels? Thanks for any hint. Zhong ```
 [Gnuplot-info] color string From: Zhong Ren - 2009-07-15 19:11:09 ```Why can't I do this? How can I fix it? Thank you. Zhong gnuplot> col(r, g, b) = sprintf('"#%X%X%X"', r, g, b) gnuplot> print col(255, 23.4, 255) "#FF17FF" gnuplot> plot sin(x) w l lc rgb col(255, 23.4, 255) ^ expected a known color name or a string of form "#RRGGBB" ```
 Re: [Gnuplot-info] color string From: Thomas Sefzick - 2009-07-16 09:48:17 ```gnuplot> col(r, g, b) = sprintf('#%X%X%X', r, g, b) gnuplot> print col(255, 23.4, 255) #FF17FF gnuplot> plot sin(x) w l lc rgb col(255, 23.4, 255) works 'sprintf' returns a string, you don't have to enclose it in quotes. renzresearch wrote: > > Why can't I do this? How can I fix it? Thank you. > > Zhong > > > > gnuplot> col(r, g, b) = sprintf('"#%X%X%X"', r, g, b) > gnuplot> print col(255, 23.4, 255) > "#FF17FF" > gnuplot> plot sin(x) w l lc rgb col(255, 23.4, 255) > ^ > expected a known color name or a string of form "#RRGGBB" > > > ------------------------------------------------------------------------------ > Enter the BlackBerry Developer Challenge > This is your chance to win up to \$100,000 in prizes! For a limited time, > vendors submitting new applications to BlackBerry App World(TM) will have > the opportunity to enter the BlackBerry Developer Challenge. See full > prize > details at: http://p.sf.net/sfu/Challenge > _______________________________________________ > Gnuplot-info mailing list > Gnuplot-info@... > https://lists.sourceforge.net/lists/listinfo/gnuplot-info > > -- View this message in context: http://www.nabble.com/3D-function-tp23965589p24513410.html Sent from the Gnuplot - User mailing list archive at Nabble.com. ```

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