## Loop over complex calculations without memory blow...

Hi Maple'primes. I have a question that I am sure has been posted many times but I will do again. I am using Maple 10 and I am trying to sweep over a parameter space with a for loop. At each iteration of the loop I am performing a complex calculation : double/triple integral or solving a boundary value problem. If I compute the compuation as a stand alone execution then it take ~ 30 sec, however, when I loop through 200 iterations the loop never finishes and Maple tells me I am out of memory. When I look at the memory (bottom right hand corner) it keep increasing to crazy levels (Gigs) during the loop, when each computaion should be about 20M. It seems like Maple keeps track of all the old computations when I clearly don't want it to. How can I speed this up?

## worksheet font? and plotting transformed data?...

2 questions I began in the worksheet mode but somehow the input font was changed from "Maple input" to "2D input". How do I maintain the "Maple input" as the default input? I am building a worksheet for nonlinear data regression. input data file 0.1 19.62 0.2 12.26 0.3 7.72 0.5 3.47 0.6 2.43 0.7 1.49 0.8 1.24 0.9 0.82 1.0 0.57 Here is what I have done thus far. Every thing works fine except for the plot call. I do not understand how plot syntax works with the sequences I made. Or am I using the wrong plot function? Thanks for you help, Bruce ---------------------------------------------------------------------

## Adding Gridlines to a Plot?...

When using the "plot" command in Maple 9, is there any way to draw gridlines on your plot?

## Execution and UI components...

Hi, I have a matrix containing data read from an external file. I would like the user to select a colon number using a List box and, based on this number, build the resulting vector from the matrix. Is it possible to ask Maple to evaluate some parts (execution groups?) of a worksheet with some command (not menus)? Thanks.

## Difference Between "&xor" and "∨"...

Does the notation (&xor) stand for the logically exclusive operator "or" where both propositions of this operator cannot both have the truth value "true" ? Also, does the notation "∨" represent the more widely used logically inclusive operator "or" where it's possible for both operands to be true ? dc.

## Maple Connect...

Does anyone here use or has ever used Maple-Connect ? Also how long were you using Maple before first attempting this ?

## Creation of a simple datafile...

How do I generate a datafile (ascii-type) for the following general case: y1:=f1(x); y2:=f2(x); ... ym:=fm(x); so that the first column will contain selected values of x from x0 to xN, the second column will contain the corresponding f1(x0..xN), the third f2(x0..xN) etc.? Thanks, Miran

## Strange results of a numerical integration...

I try to calculate a numberical integration in 2 layer for loops(outer 21 times, inner 128 times): evalf(int(erfc(sqrt(B*xgms1*x/(x*xgmi1+xgmn1)))/gamav*exp(-1*x/gamav),x=0..infinity)), i.e., the kenerl is erfc(ax/(cx+d))×exp(-ax). But when "gamav" > 100000, the calculation time is too long to bear. So I try to do some approximation and change the upper bound into 10*gamav, 30*gamav, 50*gamav and 100*gamav. But I got the following results: BER1a1[18]=0.0001004773804, BER1a2[18]=0.0000365034983, BER1a3[18]=0.0000000096250, BER1a4[18]=0.0000000000001. The trend of results is bigger the upper bound smaller the results. Obviously, the results is wrong. When "gamav" is a smaller number, such as 1000, the four integration results is the same as when the upper bound is "infinity".

## Evaluating polynomials without knowing variables?...

Hello! I would like to do something that I really think should be simple. Suppose I have a polynomial P := x^2 + y If I want to evaluate it at the point [1,2], I could say: eval(x=1,y=2,P); But suppose that I didn't know the form the variables in the polynomial would take. Or suppose that I knew they were of the form x1,x2,x3,...,xn. Given a vector of size n, how can I evaluate my polynomial at that point? Thanks! Susan

Here is my problem: I am trying to plot this: y=(pi(sqrt(4-(x^2)))/((x^2)+4) but i get this error, when trying to plot. 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 Error, empty plot please help ASAP

## vector length in Maple 10.0 Classic worksheet...

Hi. Anyone knows a command on how to calculate the norm (length) of a vector? For example: Maple input: START >restart:with(linalg):#I know this package is obsolete, but my Teach only teaches theese commands.. >u:=vector([1,1,1,1]);#a vector i defined >LengthU:=sqrt(u[1]^2+u[2]^2+u[3]^2+u[4]^2);#This is how I calculate the length theese days... END Anybody knows a command, so that my third line will not be neccesary? TIA

## Syntax for Commands in the Logic Package...

After reviewing the help pages on the Logic package I noticed that the commands used in examples usually contained an ampersand "&" before them. Does this in any way alter the meaning of the logical operator or (connective) in any from it's usual meaning in standard text ? for example, is &iff "if and only if" ? does ∧ stand for "and" ? does ∨ mean the logically inclusive "or" does &implies mean "if antecedent then consequent" ? and so forth... Dan