error when use maple formula in matlab

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ebi
ebi 2013-10-20
评论： Walter Roberson 2013-10-22
in maple i can define formula very simple and we can use maple formula in matlab in some way, in my program it not work and has error. please check it .
clc
clear
L=input(' define L (lenght of wagon -m) : ');
V=input(' define V (speed of train -km/h) : ');
X1=input(' define X1(distance betwean 2 wagon -m) : ');
X2=input(' define X2(distance betwean 2 middle wheels -m): ');
X=input(' define X (distance betwean 2 near wheels -m) : ');
W=input(' define W (total weight of wagon and passenger -ton) : ');
disp( ' ' )
disp('Please wait 5 seconds only!');pause(1);
disp('Press any key to see All input.'); pause;
disp( ' ' )
V=V*1000/3600;disp([' *** V : (speed of train)= ',num2str(V),' m/s'])
disp([' *** L : (lenght of wagon) = ',num2str(L),' m'])
disp([' *** X1: (distance betwean 2 wagon) = ',num2str(X1),' m'])
disp([' *** X2: (distance betwean 2 middle wheels) = ',num2str(X2),' m'])
disp([' *** X : (distance betwean 2 near wheels) = ',num2str(X),' m'])
disp([' *** W : (total weight of wagon) = ',num2str(W),' ton'])
F1=W*9.81/8;
disp([' *** F1: (force of 1 wheel) = ',num2str(F1),' kN'])
%---------------------------------------------------------
t1=X/V;t2=(X+X2)/V;t3=(2*X+X2)/V;t4=(2*X+X2+(L-X2-2*X)+X1)/V;
disp([' *** F1 = ',num2str(F1),' kN'])
disp([' * t1 = ',num2str(t1),' s'])
disp([' * t2 = ',num2str(t2),' s'])
disp([' * t3 = ',num2str(t3),' s'])
disp([' * t4 = ',num2str(t4),' s'])
t1 =0.0001*round(10000*t1);
t2 =0.0001*round(10000*t2);
t3 =0.0001*round(10000*t3);
t4 =0.0001*round(10000*t4);
F1 =0.0001*round(10000*F1);
maple('assign','F1',F1);
maple('assign','t1',t1);
maple('assign','t2',t2);
maple('assign','t3',t3);
maple('assign','t4',t4);
T=t4;
maple('assign','T',T);
syms t
maple('f:= piecewise(0 <= t and t <= t1, F1, t1 < t and t < t2, 0, t2 <=t and t <= t3, F1, t3 < t and t < t4, 0)');
maple('plot(f,t=0..t4)')
T=t4;
maple('a0=1/T.int(g, t = 0 .. t4)'); %coefficient of fourier series
maple('an=2/T*int(g.sin(2.n.Pi.t/T), t = 0 .. t4)'); %coefficient of fourier series
maple('bn=2/T*int(g.cos(2.n.Pi.t/T), t = 0 .. t4)'); %coefficient of fourier series
maple('plot(an,t=0..t4)')
maple('plot(bn,t=0..t4)')
maple('ft=a0+sum(an.cos(2.n.Pi.t/T)+bn.cos(2.n.Pi.t/T)), n = 1 .. 200)'); %fourier series
maple('plot(ft,t=0..t4)')
--------------------- error is
Error using maple (line 178)
Error using maplemex
Error, invalid left hand side in assignment
  2 个评论
Walter Roberson
Walter Roberson 2013-10-20
When the problem occurs, which line of your code is being executed ?
ebi
ebi 2013-10-20
first error is in line of :
maple('assign','F1',F1);
or
maple('assign','t1',t1);

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回答（2 个）

Walter Roberson
Walter Roberson 2013-10-20
Your line
maple('f:= piecewise(0 <= t and t <= t1, F1, t1 < t and t < t2, 0, t2 <=t and t <= t3, F1, t3 < t and t < t4, 0)');
correctly assigns a value to "f". But your lines starting from
maple('a0=1/T.int(g, t = 0 .. t4)');
define equations rather than do assignments.
The maple operator "=" is equation; the maple operator ":=" is assignment.
  3 个评论
显示 1更早的评论
Walter Roberson
Walter Roberson 2013-10-20
As an experiment, try using
maple('assign', 'myF1', F1);
If that works then the guess would be that F1 exists and is protected in Maple.
ebi
ebi 2013-10-20
i try it but not work have error .my input and output are :
define L (lenght of wagon -m) : 24.5
define V (speed of train -km/h) : 270
define X1(distance betwean 2 wagon -m) : 0.6
define X2(distance betwean 2 middle wheels -m): 20
define X (distance betwean 2 near wheels -m) : 1.5
define W (total weight of wagon and passenger -ton) : 100
Please wait 5 seconds only!
Press any key to see All input.
*** V : (speed of train)= 75 m/s
*** L : (lenght of wagon) = 24.5 m
*** X1: (distance betwean 2 wagon) = 0.6 m
*** X2: (distance betwean 2 middle wheels) = 20 m
*** X : (distance betwean 2 near wheels) = 1.5 m
*** W : (total weight of wagon) = 100 ton
*** F1: (force of 1 wheel) = 122.625 kN
*** F1 = 122.625 kN
* t1 = 0.02 s
* t2 = 0.28667 s
* t3 = 0.30667 s
* t4 = 0.33467 s
*|Error using maple (line 178)
Error using maplemex
Error, invalid left hand side in assignment
Error in maple_function (line 33)
maple('assign','F1',F1);|*
--------------------------------------
program is :
clc
clear
L=input(' define L (lenght of wagon -m) : ');
V=input(' define V (speed of train -km/h) : ');
X1=input(' define X1(distance betwean 2 wagon -m) : ');
X2=input(' define X2(distance betwean 2 middle wheels -m): ');
X=input(' define X (distance betwean 2 near wheels -m) : ');
W=input(' define W (total weight of wagon and passenger -ton) : ');
disp( ' ' )
disp('Please wait 5 seconds only!');pause(1);
disp('Press any key to see All input.'); pause;
disp( ' ' )
V=V*1000/3600;disp([' *** V : (speed of train)= ',num2str(V),' m/s'])
disp([' *** L : (lenght of wagon) = ',num2str(L),' m'])
disp([' *** X1: (distance betwean 2 wagon) = ',num2str(X1),' m'])
disp([' *** X2: (distance betwean 2 middle wheels) = ',num2str(X2),' m'])
disp([' *** X : (distance betwean 2 near wheels) = ',num2str(X),' m'])
disp([' *** W : (total weight of wagon) = ',num2str(W),' ton'])
F1=W*9.81/8;
disp([' *** F1: (force of 1 wheel) = ',num2str(F1),' kN'])
%---------------------------------------------------------
t1=X/V;t2=(X+X2)/V;t3=(2*X+X2)/V;t4=(2*X+X2+(L-X2-2*X)+X1)/V;
disp([' *** F1 = ',num2str(F1),' kN'])
disp([' * t1 = ',num2str(t1),' s'])
disp([' * t2 = ',num2str(t2),' s'])
disp([' * t3 = ',num2str(t3),' s'])
disp([' * t4 = ',num2str(t4),' s'])
t1 =0.0001*round(10000*t1);
t2 =0.0001*round(10000*t2);
t3 =0.0001*round(10000*t3);
t4 =0.0001*round(10000*t4);
F1 =0.0001*round(10000*F1);
%-----------------------------------------------------------
maple('assign','F1',F1);
maple('assign','t1',t1);
maple('assign','t2',t2);
maple('assign','t3',t3);
maple('assign','t4',t4);
T=t4;
maple('assign','T',T);
syms t
maple('f:= piecewise(0 <= t and t <= t1, F1, t1 < t and t < t2, 0, t2 <=t and t <= t3, F1, t3 < t and t < t4, 0)');
maple('plot(f,t=0..t4)')
T=t4;
maple('a0=1/T.int(f, t = 0 .. t4)'); %coefficient of fourier series
maple('an=2/T.int(f.sin(2.n.Pi.t/T)), t = 0 .. t4)'); %coefficient of fourier series
maple('bn=2/T.int(f.cos(2.n.Pi.t/T)), t = 0 .. t4)'); %coefficient of fourier series
maple('plot(an,t=0..t4)')
maple('plot(bn,t=0..t4)')
maple('ft=a0+sum(an.cos(2.n.Pi.t/T)+bn.cos(2.n.Pi.t/T)), n = 1 .. 200)'); %fourier series
maple('plot(ft,t=0..t4)')

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ebi
ebi 2013-10-22
is there any body help me ? is there any body want to answer my question ?
  3 个评论
显示 1更早的评论
Walter Roberson
Walter Roberson 2013-10-22
Modern student versions would be more likely to use MuPAD than Maple.
Walter Roberson
Walter Roberson 2013-10-22
I want to answer the question, but I do not have the appropriate toolboxes.

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