6,595 reputation
1524
bio website
location
age
visits member for 2 years
seen 5 hours ago

Aug
21
comment Export Grayscale Bitmap
In fairness most of the opts are documented only under Import. This one point : " Export creates a BMP file with indexed color [... ] if the ColorMap element is specified. " seems to be just wrong however.
Aug
21
comment Export Grayscale Bitmap
After playing with this a good bit looking at file sizes, the only thing that actually produces a one byte per pixel file is @SimonWoods approach of converting the type to Byte before Export sees it. (That is to say the documented options simply do not work )
Aug
20
awarded  Yearling
Aug
20
comment Example of Integrate applying a numerical evaluation N
I see that, I mean its not obvious that should cause the entire resulting expression to be evaluated numerically.
Aug
20
comment Example of Integrate applying a numerical evaluation N
nice solution, yet it is not obvious why Integrate applies N to the result in the first place.
Aug
20
comment Example of Integrate applying a numerical evaluation N
I also can not reproduce your second example -- what version?
Aug
20
answered Find Root Iteration
Aug
20
comment Find Root Iteration
mysum is not even a function of x in your sample
Aug
19
comment How to plot several functions without jumping? (multiple eigenvalues of a system as functions of 2 parameters)
@altroware fixed that issue i think - verified only with 9 which it turns out has the Indexed function (undocumented).
Aug
19
revised How to plot several functions without jumping? (multiple eigenvalues of a system as functions of 2 parameters)
deleted 13 characters in body
Aug
19
revised How to plot several functions without jumping? (multiple eigenvalues of a system as functions of 2 parameters)
added 316 characters in body
Aug
18
comment Numerically integrating a list-valued function
that issue is somewhat avoided if you do : foo[x_?NumericQ] :=foo[x]= {x^2, x^3} ( though not entirely in case NIntegrate wants to evaluate the expressions at different points )
Aug
18
answered Numerically integrating a list-valued function
Aug
18
comment Numerically integrating a list-valued function
note this is evaluating each of the list expressions twice for each x .. so it illustrates the issue but isn't likely a good approach for performance reasons.
Aug
15
comment Finding average error of the data
mike, show the LinearModelFit code you tried that fails.
Aug
13
comment How to plot several functions without jumping? (multiple eigenvalues of a system as functions of 2 parameters)
i guess the warning i surpressed got elevated to an error. i dont have 10 to work on it though
Aug
13
comment Error with “Newton's method” in Wellin's Mathematica book
my wag older mma versions didnt flag the issue with a warning (dont know how old that book is)
Aug
12
comment Measuring time complexity of a method
all you can do without acess to the details of the code is emperically evaluate for various n using timing and look at the trend
Aug
10
comment Read and write files
you should keep everything that you don't change in string format start with Import[file,{"Text","Lines"}]. Then you need to cook up the appropriate string operations to make the desired changes.
Aug
7
comment How to integrate a function which is only known at discrete points
reference.wolfram.com/language/ref/Interpolation.html