I have a 4 by 4 matrix that I need to augment to a 7 by 7 matrix.

I find I can use the "|" operator to append a column to my original matrix. So I can do this three times and I have a 4 by 7 matrix.

Now, the only way I have found to add the three rows I still need to add is to transpose, use "|" three times and to transpose back. While this indeed works it is rather clumsy and probably not efficient.

Is there a better way to do that better; i.e. is there...

I am writing a module that will have several procedures. This module will be loaded using "with(modulename)."

Inside one of the procedures (a procedure dealing with opening a data file) I am testing for the existence of a file and, if it does not exist, it should open a filedialog so I can navigate to the relevant folder that has the file. Like this (test is set from the existence-checker to be true or false):

if (not test) then # have to get and set currentdir

I have valid Maple 15 licenses both on my laptop as well as on my desktop at work. Sometimes I would like to use the kernel of the desktop version (more powerful computer with more memory) with the worksheet-GUI of my laptop esp. since on Mac the X-window interface does not work. Since Maple has a client-server architecture (or kernel-frontend), is there a way---any way---to connect to the remote kernel from my laptop? I believe Mathematica has been able to do that for years.

I have a column vector of lists. FWIW, it was generated by numerically solving an ODE and then map-ping the solution over a vector with values for the independent variable, like "yt:=map(solnn,xv)" where xv is a column vector with floats and solnn is the result of a dsolve(...,numeric). Each element of the solution vector yt has the form [t=..., y(t)=..., d/dt(y(t))=...] and has the type List.

I want to extract the solutions for y(t) (i.e. the numbers only) into a new...

I have 2 column vectors I am trying to plot against each other. The vertical axis needs to be logarithmic.

If I say

plot(mass,map(log,pressure),style=point);

it works and I get all 19 points.

If I say

logplot(mass,pressure);

I get the correct scales in both directions (so nothing would be cut-off) but it plots only 4 points.The same happens if I use plot(...,axis[2]=[mode=log]);

The pressure values range from 1E-7 to 1E-12....