@arctica1963 I'm sorry that I wasn't more specific about restart. Put the restart at the beginning of your document. It's a good idea to start all computations with restart, which erases all user-defined values from memory. It's like the "all clear" button on a pocket calculator. See ?restart. Where you have the restart now is erasing everything you just defined right before you try to plot it.

Let me know how it goes. I got the plot that you expect, except that the horizontal axis is from 0 to 512. Get the plot first, then we can rescale the axis.

@arctica1963 I'm sorry that I wasn't more specific about restart. Put the restart at the beginning of your document. It's a good idea to start all computations with restart, which erases all user-defined values from memory. It's like the "all clear" button on a pocket calculator. See ?restart. Where you have the restart now is erasing everything you just defined right before you try to plot it.

Let me know how it goes. I got the plot that you expect, except that the horizontal axis is from 0 to 512. Get the plot first, then we can rescale the axis.

In this case. the data are evenly spaced in both independent-variable dimensions, so the Matrix/GRID form of surfdata is more convenient than the listlist/MESH form.

In this case. the data are evenly spaced in both independent-variable dimensions, so the Matrix/GRID form of surfdata is more convenient than the listlist/MESH form.

Joe (and other experienced debuggers),

Try Inert:= ToInert(eval(soltn)). The result looks like the normal inert form of a procedure result from dsolve. Now do FromInert(Inert). The result is the literal symbol `invalid character in short integer encoding 70 F`.

The result is quite different if you use disassemble(eval(soltn)). Then you get an actual error message rather than a symbol: "Error, (in unspecified) Non-fatal error when reading data from kernel."

Joe (and other experienced debuggers),

Try Inert:= ToInert(eval(soltn)). The result looks like the normal inert form of a procedure result from dsolve. Now do FromInert(Inert). The result is the literal symbol `invalid character in short integer encoding 70 F`.

The result is quite different if you use disassemble(eval(soltn)). Then you get an actual error message rather than a symbol: "Error, (in unspecified) Non-fatal error when reading data from kernel."

@emma hassan You must select float[8](64-bit). Do not use the 32-bit.

Please upload a copy of the text file, after you've editted out the top row and left column, so that I can investigate. You must also edit out any blank lines.

@emma hassan You must select float[8](64-bit). Do not use the 32-bit.

Please upload a copy of the text file, after you've editted out the top row and left column, so that I can investigate. You must also edit out any blank lines.

@emma hassan When it asks you select the format of the file, choose "Delimited". On the next screen, select the default "Tab separated". On the next screen, select "float[8](64-bit)" (regardless of whether your proessor, OS, or Maple version are 64- or 32-bit).

@emma hassan When it asks you select the format of the file, choose "Delimited". On the next screen, select the default "Tab separated". On the next screen, select "float[8](64-bit)" (regardless of whether your proessor, OS, or Maple version are 64- or 32-bit).

I said use ImportData(). Your worksheet attempts to use ImportMatrix.

I said use ImportData(). Your worksheet attempts to use ImportMatrix.

I cut-and-paste your data from your original post into a blank Microsoft Notepad document. Then I editted out the extraneous info, like the top row and the left column. I saved the document, then used Maple's ImportData() command and just followed the interactive directions.

I cut-and-paste your data from your original post into a blank Microsoft Notepad document. Then I editted out the extraneous info, like the top row and the left column. I saved the document, then used Maple's ImportData() command and just followed the interactive directions.

@emma hassan Using the first table from your original post, I made it into a Matrix M as I described; and here is how to plot it:

plots:-surfdata(M, 0.05..0.85, 0.05..0.85, labels= [t,x,U], axes= boxed, title= "Crank-Nicolson");