## 110 Reputation

9 years, 290 days

## numeric stiff DAE solving...

Maple

I have read a few papers on accuracy and numerical methods to solve problems.  My personal interest is in very stiff DAE equations of state (eos) for gaseous expansions/flow problems in very high differential starting conditions for the convergence to occur in the initial time steps.

A long time goal has been to convert the FORTRAN real*16 floating point DAE solver (initially ran on CRAY) into Maple proc() using arbitrary precision that actually solves at the hardware float ieee precision.

Any reference material on stiff solvers and maple implementation would be great.

Bill

## Variables and functions, maple calculato...

Maple Calculator

Does anyone use maple calculator?

I am trying to use it on my iPad for matrix functions.

I tried standard maple %T for transpose, get an error.  I've tried -1.  No joy.

I can't seem to find how to assign to a variable, or use indexing to a matrix element.

Any suggestions welcomed for iPad maple functionality.

## animation and range problem error...

Maple

Is there a reason that an angle theta from zero to pi/2 (0 to 90 deg) returns as invalid for an animation range?  I am trying to rotate a vector 2D for visualization.  This is build-up towards a 3d rotating vector in an animation.

Here is the code: theta is the arrow tip rotation's location via cos(theta), sin(theta) coordinates in a 2D vector.

animate(arrow, [<cos(theta), sin(theta)>, width = [0.05, relative], view = [-1 .. 2, -1 .. 2], color = "blue"], theta = 0 .. Pi/2)

ErrorMessage:

Error, (in plots/animate) 0 = 0 .. (1/2)*Pi  is an invalid animation range

Bill

## Why do we use "restart" on most workshee...

Maple

This has always made me wonder everytime I type it.

The first command I always type on a new worksheet is restart.  I don't think I have never done this.

Is there a reason it needs to be manually entered and how many people DO NOT start a worksheet with a restart?

Is there a reason to not make this automatic with initial loading of a worksheet?

Thanks,

Bill

## Heat Map graphic component's editing...

Maple

Can anyone assist with Heat Map plotting questions?

I am interested in specifically formating axis.  i.e., can an axis be labels such as RPM range text =  "0-100, 101-200, 201-300", etc.  for each bin and rotated vertical to fit.   I tried most of the plot options with no success including labeldirections=[x, y].

Also, can I invert the data so the 1,1 bin is lower left corner vs upper left? tried to reverse the indices and errored with "inverted index" without resolution.

Lastly, I noted that I couldn't stack a frame Text plot of same size by assigning a plot to a variable and using display to overlay them.   The heat map is always on top and transparency option doesn't let the text come through.

Plt1 := HeatMap(Array3[2 .. 101, 2 .. 31], color = C_List, size = [750, 450], transparency = 0.5)