Thomas Dean

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18 years, 348 days

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These are questions asked by Thomas Dean

I was working through some example problems and came across this statement.  Actually comparing Sympy results to Maple. (I prefer Maple).

"Calculate the volume integral of f(...) over the sphere of radius r"

I can solve the problem, but, got hung up on the exact meaning of the problem statement.

Tom Dean

restart
with(VectorCalculus):
with(LinearAlgebra):

## http://www.acme.byu.edu/wp-content/uploads/2017/08/Sympy.pdf
## Problem 7

f := proc(x, y, z)
    (x^2 + y^2 + z^2)^2
end proc;

(M, d) := Jacobian([rho*sin(phi)*cos(theta),
                    rho*sin(phi)*sin(theta),
                    rho*cos(phi)],
                   [rho, phi, theta],
                   'determinant' );
abs(d);
simplify(%);

eqn := f(rho*sin(phi)*cos(theta), rho*sin(phi)*sin(theta), rho*cos(phi));
eqn := eqn * abs(simplify(d));

soln := int(eqn,[rho=0..r,theta=0..2*Pi,phi=0..Pi]);
subs(r=3, soln);

 

I am attempting to reproduce the results claimed by analog.com for a band pass filter.

I have checked the circuit specification and found no errors.

Am I expecting too much or am I doing something wrong?

## www.analog.com/designtools/en/filterwizard/
## Filter Requirements for Band-Pass, 4th order Butterworth
## Specifications: Optimize for Power, +Vs= 5, -Vs= -5
## Gain: 10 dB
## Passband: -3dB at 2kHz
## Stopband: -40dB at 40kHz
## Component Tolerances: Capacitor = 5%; Resistor = 1%; Inductor = 5%; Op Amp GBW = 20%

restart;
with(Syrup); Version;
with(DynamicSystems):

ckt := "*60 kHz Band Pass Filter  \n\
vin 1   0 \n\
R1A 1   2 165k \n\
R1B 5   7 169k \n\
R2A 2   0 976 \n\
R2B 7   0 1k \n\
R3A 6   0 221 \n\
R3B 11  0 226 \n\
R4A 5   6 12.7k \n\
R4B 10 11 12.7k \n\
R5A 4   3 97.6k \n\
R5B 9   8 100k \n\
R98 3   0 1e9 \n\
R99 8   0 1e9 \n\
C1A 2   4 270pF \n\
C1B 7   9 270pF \n\
C2A 2   3 270pF \n\
C2B 7   8 270pF \n\
* \n\
X1A 6  3 5  NonIdealOpAmp \n\
X1B 11 8 10 NonIdealOpAmp \n\
.include Library:-NonIdealOpAmp \n\
.end";

volts, others := Solve(ckt, 'ac', 'returnall');
gain := eval(v[10]/vin, volts);
H := subs({A=80000, f0=15*10^6, Ro=100}, gain);
evalf(H);
tf := evalf(H);
sys := TransferFunction(tf);
PrintSystem(sys);
plotsetup(maplet);
MagnitudePlot(sys);

 

I use Ubuntu 14.04 and X, not the desktop.  I use emacs/maple 2016.

GNU Emacs 25.1.2 (x86_64-unknown-linux-gnu, X toolkit, Xaw scroll bars)
 of 2017-03-1

;;; maplev.el --- Maple mode for GNU Emacs

;; Authors:    Joseph S. Riel <joer@k-online.com>
;;             and Roland Winkler <Roland.Winkler@physik.uni-erlangen.de>
;; Time-stamp: "2003-10-09 22:49:16 joe"
;; Created:    June 1999
;; Version:    2.155
;; Keywords:   Maple, languages
;; X-URL:      http://www.k-online.com/~joer/maplev/maplev.html
;; X-RCS:      $Id: maplev.el,v 1.14 2006-06-02 14:02:38 joe Exp $

I use emacs/maple mode with maple 2016.  Quite often, emacs looses connection with the maple server.  I do  not remember this happening or maybe not as often, with earlier versions of maple.

After using maple/emacs, I started xmaple.  After a few expression evaluations, the maple server stopped.  Restarting xmaple and repeating the expression evaluations many times, I do not get the crash.  So, this appears to be a difficulty with external connections to the maple server.

Does a later version of maple mode exist?

 

I expected plot with an undefined name to do nothing, but,

plot(asdf);

actually plots y=x!

This is reduced from another forum.

restart;
e1 := 12*g^2+12*h^2+4*i^2+3*j^2=684;
e2 :=  12*l^2+12*m^2+4*n^2+3*o^2=684;
e3 := 12*q^2+12*r^2+4*s^2+3*t^2=172;
e4 := 12*v^2+12*w^2+4*x^2+3*y^2=108;
e5 := 12*g*l+12*h*m+4*n*i+3*j*o=-84;
e6 := 12*g*q+12*h*r+4*s*i+3*j*t=-84;
e7 := 12*g*v+12*h*w+4*x*i+3*j*y=-84;
e8 := 12*l*q+12*m*r+4*n*s+3*o*t=-84;
e9 := 12*l*v+12*m*w+4*n*x+3*o*y=-84;
e10 := 12*q*v+12*r*w+4*s*x+3*y*t=-84;
e11 := g+h+i+j=-1;
e12 := l+m+n+o=-1;
e13 := q+r+s+t=-1;
e14 := v+w+x+y=-1;
e15 := h*i+m*n+3*s*r+4*x*w=-21;
e16 := g*i+l*n+3*s*q+4*x*v=-21;
e17 := i+n+3*s+4*x=-3;
e18 := g*h+m*l+3*q*r+4*w*v=-7;
e19 := h+m+3*r+4*w=-1;
e20 := g+l+3*q+4*v=-1;
e21 := i*j+o*n+3*s*t+4*x*y=-84;
e22 := j*h+o*m+3*r*t+4*y*w=-28;
e23 := j*g+o*l+3*q*t+4*y*v=-28;
e24 := j+o+3*t+4*y=-4;
e25 := j^2+o^2+3*t^2+4*y^2=144;
e26 := i^2+n^2+3*s^2+4*x^2=129;
e27 := h^2+m^2+3*r^2+4*w^2=57;
e28 := g^2+l^2+3*q^2+4*r^2=57;

eqset := {e1, e2, e3, e4, e5, e6, e7, e8, e9, e10, e11, e12, e13, e14, e15,
          e16, e17, e18, e19, e20, e21, e22, e23, e24, e25, e26, e27, e28};
for s in eqset do print(s) end do;

Error, too many levels of recursion

If I then do

S := {1,2,3,6,3,6,8,2,3,6};

for s in S do print(s) end do;

Then,

for s in eqset do print(s) end do;

has the correct output.

What am I doing wrong?

Tom Dean

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