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The TI's come with different pixel resolutions. I have a TI83+SE which has 96 X 64. The 48's are 131 X 64. I think the higher end TI's have higher resolution than the 48's. More pixels take more time to draw (all other things being equal). This might have some bearing on the relative speed of the plotting functions. Another important factor might be the precision used to calculate the pixel coordinates. Since there are less than 256 pixels on either axis, 8 bit integer math would be sufficient. I don't think the processor in the 48's is capable of low precision math. The TI83 has a Z-80 processor and even if it is emulating high precision BCD math to evaluate the function to be plotted, it can use 8 bit integer math to calculate the physical pixel coordinates once the function value is calculated. Scaling and clipping are two steps that have to be performed for each pixel after the function is evaluated. If the TI's are doing these steps with 8 bit integer math, it would take much less time than the full precision BCD math that the 48 has to do. One final thing that might be involved is the range checking that the 48 operating system does. As I understand it, the difference between User and System RPL has to do with this range checking that is done before every operation in User RPL, but which is bypassed in System RPL. I wonder if there is any way to specify the equation on a 48 using Sytem RPL?

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Hi;

I am not sure about it, but I think it's possible to find integer numbers faster than a full-precision floating point in the same expression. If so, I think it would be wise using an integer-number ploter program to evaluate the expression and give final coordinates directly. I am beguining to use a TI82 (thanks to Michel Beaulieu) and I see it creates faster table and ploted dots. I see that resolution interferes in table-building speed.

Maybe thsis is the goal: why to obtain floating point numbers from an expression if I need only integers to plot it, say, to plot pixels?

Just a guess.

Luiz C. Vieira - Brazil

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the 28 has such a small graphic screen it is silly and the 48 has all the features but is just too darn slow. embarrassingly slow, in fact.

i am sorry to say this because i got excited by both machines initially because they could actually do graphics at all. nowdays its commonplace.