@vv My code above works just as well (meaning without apparent effort) for thousand-bit keys also. I just used a 70-bit key because I wanted it all to fit nicely in the post.

Just do RSA:-GenKey(512);

@student_md The last line of my Answer can be used to "flatten" or "remove the brackets" from Tom's Answer, if you take his Matrix P and use it as the T in my code.

But I suspect that Acer has a more-efficient Answer. I haven't analyzed his yet.

@666 basha So heat transfer = Nu? That's all that you needed to say several replies ago. I know how to translate numbers into colors.

Nu: symbol, concept that I understand;
Translating symbols to numbers: concept that I understand;
Translating numbers to plot colors: concept that I understand.

But...

"heat transfer": concept that I don't know much about.

It'll probably take me a day to get to it.

@tomleslie I just posted a complete implementation of RSA. The OP's procedure is equivalent to my procedure Stringify.

@666 basha Okay, I understand your desired color scheme. But what is the heat transfer formula? (And why didn't you answer that before?) Please remember that I don't know the first thing about fluid mechanics. (I'm not even sure that the field that we're discussing is properly called "fluid mechanics".) All I know is

• symbolic computation
• numeric computation
• abstract ODEs
• how to solve ODEs numerically
• how to plot the solutions with Maple.

@Rohith  The issue that you present is not really about denominators; rather, it's about nested expressions. Since you had indets[flat] rather than indets in your Question, I used flat in my Answer, which avoids nested expressions; I assumed that that's what you wanted. The expression that you're trying to extract in this case, a*cos(psi)*sin(a)^2, is a `*` inside a `+` inside a `*` (because division is `*` also) inside a `+`. Regular indets will find it no matter how deeply it's nested, but indets[flat](..., `*`) will ignore it.

So, try this

getFuncCoeff:= proc(e)
local 
   One,
   Funcs:= [select(
      x-> membertype({function, function^anything}, {op(x)}),
      indets(subsindets(e, function, f-> One*f), `*`)
   )[]],
   Coeffs:= subsindets(Funcs, {function, identical(One)}, 1)
;
   eval(Funcs, One= 1), Coeffs
end proc;

@666 basha What is the formula for heat transfer in terms of the parameters of this BVP system? Is it the Nusselt number? Do you want higher heat transfer values at the red end of the spectrum or the violet end?

@666 basha I said to replace mul with (`*`@op), but you've replaced it with `*`@op. The parentheses matter.

@666 basha So, you want the coloring that's used for the 3D surface to be used for the 2D contour plot? And do you want that shown in 2D or 3D? And what coloring do you want, the X*Y that you show? What's the relevance of that?

@666 basha 

I said to replace mul with (`*`@op), but you have just replaced it with op. Just using op will remove all the cross-product terms from the model.

"Model is not of full rank" generally means that the data has insufficient variation in at least one of the input parameters. The input parameters in this case are  [S, Ha, Rd, Ec, Nt, Nb]. The data is collected over the course of running the worksheet. Each plot varies at most 2 parameters. If you run all the plots in the worksheet as I presented it, there will be about 15,000 data points with sufficient variation for Fit to not give the warning. If you continue to have this problem, let me know.

@666 basha The one-argument forms of mul and add were added after Maple 18. To retrofit, replace mul with (`*`@op).

@666 basha The plot that you show is generated by procedure ParamPlot3d. Inside that procedure, a 2D version of the contour plot is created and assigned to local C. So, you just need to make the first line of the body of the procedure (i.e., after the local declarations) 

return C;

Why is there no Spam button on this? And there is no Delete option on the More pull-down.

I don't think that this is ever supposed to happen: I get different results from using `assuming` in infix operator form:

int(GAMMA(a,s)*exp(-b*x), s= 0..infinity) assuming b > 0, a > 0

This gives me the simple result that you were expecting. However, the functional form,

`assuming`([int(GAMMA(a, s)*exp(-b*s), s = 0 .. infinity)], [b > 0, a > 0])

returns unevaluated. I believe that assuming commands entered in 2D Input are always converted to the functional form before execution. Note that `assuming` is a Maple-language procedure on which you can run showstat, trace, etc. I've done that, but I can't figure out what's going on.

@tomleslie wrote:

• What you have is a simple substitutional code which converts a supplied integer to a text message. Pretty sure this has nothing to do with any RSA cryptosystem.

The steps for encrypting via RSA (and other cryptosystems based on modular arithmetic) are

1. Break the plaintext up into string chunks of a length such that when they're converted to numbers, the modular arithmetic will be injective (i.e., one-to-one).
2. Convert each chunk into an integer. Simply converting the bit pattern into a binary integer is sufficient.
3. Apply the mathematical part of the algorithm to those integers.
4. Output the new integers in a suitable format (possibly encoding as characters).

To decrypt, those steps are simply done in reverse (of course with some variation of the mathematical part). The OP's procedure is the second-to-last of those steps.