brownr

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These are questions asked by brownr

Using Maple 2018.2.1, I'm receiving a lost kernel message when importing the attached data file with ImportMatrix. I traced the issue to a "*" symbol at the end of the file but would have expected this to cause an error message (if any error at all) instead of the connection to the kernel to be lost. Is this a bug or am I misunderstanding the usage of ImportMatrix?

test.mw

test2.txt

I’m using Maple 2015.2 to plot irregular spaced data using the surfplot command. The shape of the plot is as expected, however I’ve been unsuccessful in changing the color of the surface. I would like the surface to be a consistant color instead of the “rainbow” color scheme. I’ve tried both the color and colorscheme options to no avail.  I’m sure I’m making a very basic mistake, however I’m having difficulty finding it.

 

See attached worksheet

 feildstrength.mw

Best regards,

Ron

[EDIT]: Worksheet didn't attach the first time

I’ve been having some issues working with large datasets / matrixes in maple 17.02 and 2015. My data consists of a 10^7 x 14 csv file with several lines of header information. Attached is a small sample. The ImportData assistant hangs while importing said file. The javaw process stops responding for a period of time then stops consuming cpu time. I’ve have successfully imported a file of the same format but reduced in size (10^6 x 14) with this same function. So I don’t believe it’s a formatting issue but rather its size.

Are there size limitations to the ImportData function?

The attached maple file has a test case in which the data set (sans header info) is created and exported as a csv file. The export time took longer than I expected (~2 hrs). I then attempted to import the file using two different functions. The ImportMatrix function successfully imported the test case file in approximately 20 minutes, however the ImportData functions seems to fail in the same way as it does importing my actual dataset. I haven’t successfully used the ImportMatrix function on my actual dataset; I’m assuming the header information is the source of the problem.

Are there other methods to import this data?

As stated above, I’m tried both maple 17 and 2015 both 64 bit versions running on an Intel i7 M620 @ 2.67Ghz, 8 GB ram (~ 6 GB avail), sata 2 ssd.

Thank you,

Ron

importtest.mw  Sample.txt

 

What is the value of u1 in this u substitution to go from -2*Pi*(int(sqrt(-3*u^2+4), u = 1 .. 0)) to -2*Pi*(int((4/3)*sqrt(3)*cos(u1)^2, u1 = (1/3)*Pi .. 0))? I'm just not seeing it.

 

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