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Nov
29
comment Raspberry Pi GPIO operations with Mathematica
updated docs here reference.wolfram.com/language/guide/ConnectingToDevices.html For ConnectingToDevices There is a whole page on reference.wolfram.com/language/guide/RaspberryPi.html RaspberryPi (I never heared of RaspberryPi before the last week, but it must be important)
Nov
29
comment How to represent very long integers with at-most-8-digit(base-10) short integers with * and +
short integers (not more than 6 decimal digits). Can you clarify this with an example? How can an integer have decimal digits? something with decimal point is not an integer, right? or are you using different notations?
Nov
29
comment Compute ratios of elements in two lists
But Kuba you can't do the division "a/b" in first place if there was a zero in list "b" ? A check is needed before
Nov
29
comment Compute ratios of elements in two lists
But Bill you can't do the division "a/b" in first place if there was a zero in list "b" ? A check is needed before.
Nov
28
comment Problem using WhenEvent to constrain solution
@Julian I can't tell now why it failes for over 1 second. But looking at your matlab code, in there, you are not using ode45, but using simple Euler steps. So your Matlab solution itself might not be accurate. If all else fails, you can code it in Mathematica the same way as you did it in Matlab, i.e manual integration. What happens is that the ps-p1[t] becomes negative at one point, and sqrt returns complex then. But you really need to first write down a mathematical model of your equations, for your own benefit.
Nov
28
comment Problem using WhenEvent to constrain solution
WL result It looked like the Matlab image to me. Can you post the text of the full Matlab code which you say works so one can compare easier? Hard to read code from an image.
Nov
28
comment Integrating a BesselJ integrand to obtain the same result as Maple 16
@AlexeiBoulbitch thanks :) @ learner123, actually I was just lucky I found it. I was hoping if I can find different form, that will send Integrate into different code path to allow it to do it. So I looked at all the different possible transformations to other special functions from BesselJ, tried few and none worked, and just before I gave up, HypergeometricPFQ worked. I used Maple's nice convert commands to try different forms, then copied each form to Mathematica and tried them to see if it will work or not. That is how I found it.
Nov
28
comment How to get list of duplicates when using DeleteDuplicates?
Nice. Now would it not be good if Mathematica DeleteDuplicate returned both of these lists as well? (if user wanted)
Nov
28
comment How to get list of duplicates when using DeleteDuplicates?
@Kuba actually I found couple of places where they talk about finding positions of duplicates in lists but did not yet understand the code. I was hoping that DeleteDuplicate can do it. But if you know of an easy way to get list of duplicates (without using DeleteDuplicates) that will work also. Thanks.
Nov
28
comment Is it possible to disable assumptions used by FullSimplify for zero testing
It will nice if one can have a small example also.
Nov
28
comment Dsolve not working
doing ClearAll[u,t] should have been enough. You do not need to do ClearAll[u'[t]], any way, as long as it works now.
Nov
28
comment How to monitor the progress of a plot
see mathematica.stackexchange.com/questions/30540/… Assuming this is what you meant by "monitor progress of a plot", otherwise if you just mean how to see the plot itself being painted on the screen step by step, that is something else....you can use something like Animate[Plot[Sin[a x], {x, -Pi, Pi}], {a, 1, 10}] for this.
Nov
28
comment Dsolve not working
It is Clear, nor clear. But Clear[u,t] should have worked.
Nov
28
comment Dsolve not working
Try restarting the kernel. From menu, Evaluation->Stop Kernel. Then type what I typed above again, you should get same result.
Nov
28
comment Dsolve not working
It is correct solution. May be using this form makes it easier Clear[u, t]; DSolve[u'[t] == u[t], u[t], t] which gives u[t]->E^t C[1] or even shorter u[t] /. First@DSolve[u'[t] == u[t], u[t], t] which gives E^t C[1] the C[1] is the constant of integration.
Nov
27
comment Is Mathematica comparable to C++ for creating standalone applications?
I wish WRI would make an actual compiler that generates a .EXE. Matlab has one (even though the generated code runs at the same speed as the interpreted version since it is not a real compiled native, but to Matlab pcode, but runs under a run-time library (the actual engine), which is native), it still allow one to make a .EXE of a Matlab GUI apps. I think WRI can make a similar thing. That will go a long way to making Mathematica more used. Make it free compiler, no restriction.
Nov
27
comment How to typeset a system of equations with multiple alignment points
fyi, question is posted at community. community.wolfram.com/groups/-/m/t/161293?p_p_auth=jAPxO1LC please do not post in two places without pointing links to each others. Someone might end up wasting their time trying to solve something already solved or ask a question already answered at the other place.
Nov
27
comment Treat all variables as local in a module
@Szabolcs but OP said In most languages, any variable declared inside a function is considered local. and I was replying to this. But any way. I myself do not languages that makes things implicit like this. I prefer explicit declarations. Much better in the long run. It helps build better software and better habit to learn to declare something before using it.
Nov
27
comment Treat all variables as local in a module
In most languages, any variable really? What about Ada, Pascal, C, C++, Java, SNOBOL, PLI, COBOL? don't you have to declare variable? I much prefer Mathematica way. It is a form of documentation. One can look at the list of local variable and know which are local or which are not. Languages that do not require declaration are sloppy languages IMNSHO. ofcourse, in Mathematica, you do not have to declare local symbols as local, but this is bad, since they will become global. I think Mathematica got it right here.
Nov
27
comment Is Mathematica comparable to C++ for creating standalone applications?
You are doing a school project that involves all that? This sounds like an operating system you will be building :) But you can browse demonstrations.wolfram.com and see what kind of apps are there. Some are simple and some are more complex. Mathematia is more higher level language than C++. If you want to do lots of system level stuff, it might not be the best for that. But if you want to spend more time on the science and analysis and the GUI part, then Mathematica is best for that. It makes building GUI much simpler than Qt and Java.