Here's a question I was asked very recently: "When creating a plot, is it possible to specify the points at which the input expression should be evaluated?" The answer is "yes" for 2-D plots, and this is done with the 'sample' option. Use the command plot(f(x), x=a..b, sample=[x1, x2, ..., xn]) to have f(x) evaluated at points x1, x2, ..., xn. Note this produces a plot that includes points with x-values x1, x2, ..., xn. To produce a plot that contains only these points, you need to add the adaptive=false option as well.

I want to solve the following task efficiently. I need to read data from S files (in my case S = 50000). Each file has T rows of 5 floats each. Here T=1000 is a time index and 5 is the dimension of a dynamical system. From each file I want to read the j coordinate and to assign its T values to a column in a matrix X. At the end of this process I'll have an X array or matrix of dimension T x S. How can I do this efficiently? When I use 'readdata' in order to read the Tx5 matrix from a single file into a list D, this is a fast process. But assigning, naively, the j column from this matrix to my matrix X, using a for loop,

Hi, I am Er. Vishal Jain new to maple prime. I need help in developing dynamic 2D-graphs(pi-chart, conic section etc.) in .mw and respectively shade the graph.

The first example below seems OK. But, should I be expecting the different behaviour in the second example?


> restart:
> p := module() option package; export foo;
> foo:=proc(x) x; end proc;
> end module:

> foo := proc(x) cos(x); end proc:

> foo(3.2);
-0.9982947758

> p:-foo(3.2);
3.2

> evalhf(p:-foo(3.2)); # OK
3.20000000000000018

> restart:
> p := module() option package; export sin;

While posting an initial question is not problematic, when editing or adding a comment thereafter, one is presented with a box in which to compose that is partially concealed by content at the right of the screen, e.g., Active forum topics and Recent comments. One can continue to type behind the veil and have it display fine in the preview, but this seems anomalous. I have noted it on two different computers. Do others have this problem? Is there a way to work around this besides truncating ones sentences with early returns?

As per instructions at the bottom of page 217 of the user manual, I wish to alter the y-axis range of a 2D plot. The instructions say to right click the plot region. Select axes and then range, however, doing so allows one to select axes, but the menu item range is nowhere to be found in the menu as described by the manual. The menu only offers the choices of normal, boxed, framed, none, properties, labels, toggle gridlines, and set gridline properties.

My old Mathcad 7 had a snap to function that allowed one to trace a given plot. Using the point probe on Maple does not seem to have an equivalent feature. If one wants to know a particular x y location, one must hover the point probe over the desired spot, but this is not ideal as it it very sensitive to movement. Is there a snap to feature for tracing plots? If so, how is is activated?

im new so excuse the relavie easy ness of this question. i typed >plot(1/7-5*(sin(x)),-10..10,-10..10); then Warning, unable to evaluate the function to numeric values in the region; see the plotting command's help page to ensure the calling sequence is correct and an empty graph comes up i looked on the help page but i dont really understand it, i was hoping mapleprimes can help??? once again sorry for the easyness of the question!!!

Hi I am trying to combine a previous, numerically obtained result in a subsequent calculation: outline: suppose i have a given function, f(x), and i wish to construct the following boundary value problem: y''(x)=f(x), y(0)=1, y(1)=2 the known function f(x) is a result of another calculation, which i have obtained numerically. (f(x)=proc(x)...end proc, or something to that affect). code: -------------------------------------------- > restart; > sys := {diff(y(x), x) = x, y(0) = 1}; / d \ { --- y(x) = x, y(0) = 1 }

How can I create the inert form of the following function: dm:=z->diff(z,t)+v[c]*d_[c](z); Note d_ is the new indicial differential operator available in physics package of Maple 11. Its inert form is %d_. What I need is that when I write, dm(rho), maple does not expand it into two terms using the above function, but displays the compact form dm(rho). I want to see the expanded form, only when needed, not at every step where dm is used. So at other steps, I just want to see dm(rho), without evaluation. Thanks, Pawan Takhar

In the example below, the plot option axesfont affects both axes in Maple 10.06, but in Maple 11.01 it affects only the vertical axis. Is this a feature, or a bug? If it’s a feature, how can I change the font of the horizontal axis tickmarks?

restart;
dates := [0 = "21/8/00", 140 = "8/1/01", 536 = "8/2/02", 885 = "23/1/03", 1267 = "9/2/04", 1628 = "4/2/05", 2004 = "15/2/06", 2200 = "30/8/06", 2479 = "5/6/07", 2531 = "27/7/07"];
xy := [[0, 2.5], [140, 2.2], [536, 2.6], [885, 2.5], [1267, 3.3], [1628, 3.1], [2004, 5.0], [2200, 3.0], [2479, 5.9], [2531, 4.3]];
plots[pointplot](xy,symbol=circle,tickmarks=[dates,default],axesfont=[TIMES,ROMAN,8]);

This question was already raised before. Does Maple 11 "fortran" command generates code which is compatible with Fortran 90 (or 95)? I have a problem in several respects, especially in the syntax of "continuation" lines. How can I generate Fortran 90 syntax. To be more specific: When long line is of code is generated 'number' sign is used to continue on the new line. In fortran 90 '&' sign is expected. i.e. fortran 77: #2*rho1(i+32 #)*rho1(i+11)-0.2037715763 instead we need in fortran 90: & 2*rho1(i+32 & &)*rho1(i+11)-0.2037715763 &

I just uploaded the file: 2510_CDR_MESH_problem.mw. I'm running Maple 10.05. The problem is more curiosity and annoyance than practical, at this point, but: If I remove the with(RealDomain) at the top of the file, everything runs fine and a nice plot is produced. Keeping the with(RealDomain) statement, results in ERROR, invalid object in MESH. Can anyone tell me what's going on? Don Ritchie

I need to put all these things together to make a scene, I would like to keep the house,and the clouds as a background plot, and have the tornado and tire move. Sort of like the tornado picks up the tire and then drops it. here is my code its to big for me to save it on here. Using like the animate code, and display codes. Packages: with(plots):with(plottools): Tornado: Actual Tornado: tubeplot([20*t*cos(t),20*t*sin(t),20*t], t=0..20*Pi, radius=-100*exp(.00001*t), tubepoints=10, numpoints=100, color=grey, frames=30): Animated Tornado: rotating around: animate(tubeplot,[[20*t*cos(t+s),20*t*sin(t+s),20*t+s],

I need to calculate derivative of a scalar function psi, which depends upon the scalar theta and tensor G[i] using the diff command and indicial notation capability of the recently included Physics package. My actual equation is longer, but here I am only including the terms needed to present my question. Please see below:

restart;

with(PDEtools):

> with(Physics):

Setup(dim=[3,`+`],spacetimeindices=lowercaselatin);