## How do I increase the memory allocation in Maple?...

Hi,

I am trying to find the inverse of 8x8 generic symbolic matrix. Everytime I evaluate the program I get the following error:

Error, (in expand/bigprod) Maple was unable to allocate enough memory to complete this computation. Please see ?alloc

Can anyone guide me how to increase the memory allocation? And would that solve the problem for me?

Any help is appreciated.

Thanks!!

## solving a symbolic inequality...

Hi, those who are in mapleprimes.

i have a problem in solving inequality with symbolic notated parameters.

I wrote the following code to solve for n(SPH), but couldn't obtain any result but an error message.

solve(-s*(-n(SPF)*tau+n(SPH))/(tau-1) <= n(SPH),n(SPH)) assuming (tau<1,s>0,s<1,tau>0);

The error was

Error, (in assuming) when calling 'unknown'. Received: 'invalid input: Utilities:-SetSolutions expects its 2nd argument, solutions, to be of type ({list, set})({piecewise, ({list, set})({name, relation})}), but received [s = -tau~+1, [SPF = SPF, s = s, tau~ <= 0]]'

Please tell me how I should do to solve the inequality.

taro

## Eigenvectors of a big matrix...

Hi there

I have have a 18*18 matrix which almost each of its element are in symbolic form. Now I need to have all of its eigenvectors. Unfortunately when I use the "Eigenvalues()" function in maple i got nothing. In fact I got the error which comes below.

Error, (in content/polynom) general case of floats not handled

I need to know if there's a solution to eliminate the error? If not, what can I do to determine the eigenvectors and eigenvalues in symbolic form?

## How to obtain a symbolic set of solutions containi...

Hello Maple-Primers!

I am trying to evaluate a system at many different points.  I would like to include an interpolation function in this system, but have thusfar been unsuccessful.

Usually, I solve a system symbolically by using eliminate and unapply:

eq[1] := A = M^3;
eq[2] := C = A*2;
eq[3] := D = N+3;
eq[4] := B = piecewise(A = 0, 0,C);
eq[5] := E = B*D;
elimsol:=eliminate(convert(eq,list),[A,B,C,D,E])[1];

unappsol:=unapply(elimsol,[N,M]);

unappsol(1,2);
{A = 8, B = 16, C = 16, D = 4, E = 64} <--- great!

Now, I want to include an interpolation function in the system of equations.  They look like this (see worksheet for actual interpolation function):

B_interp := (W,T) -> CurveFitting:-ArrayInterpolation([FC_Map_W,FC_Map_T],FC_Map,Array(1 .. 1, 1 .. 1, 1 .. 2, [[[W, T]]]),method=linear);

eq[5] := E = B_interp(N,M);

Error, (in CurveFitting:-ArrayInterpolation) invalid input: coordinates of xvalues must be of type numeric <-- bad!

Anyone have any ideas?  I've tried to use polynomials, but I can't seem to get a fit close enough for my purposes.

Maple_2D_Interpolate_FC.mw

## Solving a nonlinear system of equations in Maple...

Hello,

I am new to this forum. I have typed the follwing code in Maple17:

restart; eq1 := A-B*a-V*a*q/z-W*(b+d)*a/z = 0; eq2 := W*(b+d)*a/z-V*b*q/z-(F*G+B+D)*b = 0; eq3 := V*a*q/z-W*c(b+d)/z-(B+C+E)*c = 0; eq4 := V*b*q/z+W*(b+d)*c/z-(B+C+D+F)*d = 0; eq5 := G*F*b-V*q*e/z-(B+H)*e = 0; eq6 := H*e-V*q*f/z-(B+S)*f = 0; eq7 := S*f-V*q*g/z-B*g = 0; eq8 := V*q*g/z+S*s-(B+C+E)*h = 0; eq9 := F*d+V*q*e/z-(B+C+H+T)*t = 0; eq10 := H*t+V*q*f/z-(U+B+C+2*S)*s = 0; eq11 := T*t+W*(b+d)*x/z-(B+H+Y)*u = 0; eq12 := U*s-(B+S)*v+H*u-Y*H*v/(H+S) = 0; eq13 := g-c-d-t-s-h = 0; eq14 := z-a-b-c-d-e-f-g-h-s-t-u-v = 0; soln := solve({eq1, eq10, eq11, eq12, eq13, eq14, eq2, eq3, eq4, eq5, eq6, eq7, eq8, eq9}, {a, b, c, d, e, f, g, h, q, s, t, u, v, z});

This is to symbolically solve a nonlinear system of (14) equations. But when I press Enter, it just returns the message "Ready". Shouldn't it say "Evaluating"?

I don't see anything syntactically wrong with my code...

## Solve taking forever then not finding a solution...

Hi MaplePrime-ers,

I'm using the following piece of code to (i) solve the system of symbolically, so I can (ii) evaluate equations quickly at many points of time.  This works quite well for 4 defined values, but I'm having problems adding a 5th defined value.  Specifically, solve leaves the "solution may be lost" message after taking forever.  As the symbolic solution will be run mulitple times by a optimziation algorithm, I'd ideally like to get the solve time under 2 minutes.  I've attached both executed worksheets.  Is there anything I can do to have solve work as I intend?

This first code snippet achieves what I would like to do Series_noGear.mw:

#Interconnection Equations
eq2[1] := FD_T + EM2_T = 0;
eq2[2] := ICE_T + GEN_T = 0;
eq2[3] := EM2_A + GEN_A + BAT_A = 0;
eq2[4] := -FD_W + EM2_W = 0;
eq2[5] := -ICE_W + GEN_W = 0;
eq2[6] := -EM2_V + GEN_V = 0;
eq2[7] := -EM2_V + BAT_V = 0;

#ICE
eq_c[1] := ICE_mdot_g= ICE_T * ICE_W;

#BAT
eq_c[2] := BAT_V = 271;

#EM2
EM2_ReqPow_eq := (-148.3) + (4.267)*abs(EM2_W) + (12.77)*abs(EM2_T) + (-0.0364)*abs(EM2_W)^2 + ( 1.16)*abs(EM2_W)*abs(EM2_T) + (-0.258)*abs(EM2_T)^2 + ( 0.0001181)*abs(EM2_W)^3 + (-0.0005994)*abs(EM2_W)^2*abs(EM2_T) + ( 0.0001171)*abs(EM2_W)*abs(EM2_T)^2 + (0.001739 )*abs(EM2_T)^3 + (-1.245e-07 )*abs(EM2_W)^4 + ( 1.2e-06)*abs(EM2_W)^3*abs(EM2_T) + ( -1.584e-06)*abs(EM2_W)^2*abs(EM2_T)^2 + ( 4.383e-07)*abs(EM2_W)*abs(EM2_T)^3 + (-2.947e-06)*abs(EM2_T)^4;
eq_c[3] := EM2_P = piecewise( EM2_T * EM2_W = 0, 0, EM2_W*EM2_T < 0,-1 * EM2_ReqPow_eq, EM2_ReqPow_eq);
eq_c[4] := EM2_A = EM2_P/EM2_V;

#GEN
GEN_ReqPow_eq:= (-5.28e-12) + ( 3.849e-14)*abs(GEN_W) + (-71.9)*abs(GEN_T) + (-1.168e-16)*abs(GEN_W)^2 +(1.296)*abs(GEN_W)*abs(GEN_T) + (2.489)*abs(GEN_T)^2 + (1.451e-19)*abs(GEN_W)^3 + (0.0001326)*abs(GEN_W)^2*abs(GEN_T) + (-0.008141)*abs(GEN_W)*abs(GEN_T)^2 + (-0.004539)*abs(GEN_T)^3 +(-6.325e-23)*abs(GEN_W)^4 + (-2.091e-07)*abs(GEN_W)^3*abs(GEN_T) + ( 3.455e-06)*abs(GEN_W)^2*abs(GEN_T)^2 + ( 2.499e-05)*abs(GEN_W)*abs(GEN_T)^3 + (-5.321e-05)*abs(GEN_T)^4;

eq_c[5] := GEN_P = piecewise(GEN_T * GEN_W = 0, 0, GEN_W*GEN_T < 0,-1 * GEN_ReqPow_eq, GEN_ReqPow_eq);
eq_c[6] := GEN_A = GEN_P/GEN_V;

#assumptions
assume(BAT_V::nonnegative);
assume(FD_W::nonnegative);

termeqs := {eq_c[1],eq_c[2],eq_c[3],eq_c[4],eq_c[5],eq_c[6]};

sys_eqs2 := termeqs union convert(eq2,set);

drivers2:= {ICE_T,ICE_W,FD_T,FD_W};
symvarnames2:=select(type,indets(convert(sys_eqs2,list)),name);
notdrivers2:=symvarnames2 minus drivers2;

sol2:=solve(sys_eqs2,notdrivers2) assuming real;

symb_sol2:=unapply(sol2,[drivers2[]]);

symb_sol2(1,2,3,5);

#Enumerate (there will generally be about 40, not 3)

count := 0;
for i1 from 1 to 3 do
for i2 from 1 to 3 do
for i3 from 1 to 3 do
for i4 from 1 to 3 do
count := count + 1;
solsol2(count) := symb_sol2(i1,i2,i3,i4);
od;
od;
od;
od;
count;

This second code snippet includes the changes in bold, which make solve take forever Series_addGear.mw:

#Interconnection Equations
eq2[1] := FD_T + EM2_T = 0;
eq2[2] := ICE_T + GBb_T = 0;
eq2[3] := EM2_A + GEN_A + BAT_A = 0;
eq2[4] := -FD_W + EM2_W = 0;
eq2[5] := -ICE_W + GBb_W = 0;
eq2[6] := -EM2_V + GEN_V = 0;
eq2[7] := -EM2_V + BAT_V = 0;
eq2[8] := GBa_T + GEN_T = 0;
eq2[9] := -GBa_W + GEN_W = 0;

#ICE
eq_c[1] := ICE_mdot_g= ICE_T * ICE_W;

#BAT
eq_c[2] := BAT_V = 271;

#EM2
EM2_ReqPow_eq := (-148.3) + (4.267)*abs(EM2_W) + (12.77)*abs(EM2_T) + (-0.0364)*abs(EM2_W)^2 + ( 1.16)*abs(EM2_W)*abs(EM2_T) + (-0.258)*abs(EM2_T)^2 + ( 0.0001181)*abs(EM2_W)^3 + (-0.0005994)*abs(EM2_W)^2*abs(EM2_T) + ( 0.0001171)*abs(EM2_W)*abs(EM2_T)^2 + (0.001739 )*abs(EM2_T)^3 + (-1.245e-07 )*abs(EM2_W)^4 + ( 1.2e-06)*abs(EM2_W)^3*abs(EM2_T) + ( -1.584e-06)*abs(EM2_W)^2*abs(EM2_T)^2 + ( 4.383e-07)*abs(EM2_W)*abs(EM2_T)^3 + (-2.947e-06)*abs(EM2_T)^4;
eq_c[3] := EM2_P = piecewise( EM2_T * EM2_W = 0, 0, EM2_W*EM2_T < 0,-1 * EM2_ReqPow_eq, EM2_ReqPow_eq);
eq_c[4] := EM2_A = EM2_P/EM2_V;

#GEN
GEN_ReqPow_eq:= (-5.28e-12) + ( 3.849e-14)*abs(GEN_W) + (-71.9)*abs(GEN_T) + (-1.168e-16)*abs(GEN_W)^2 +(1.296)*abs(GEN_W)*abs(GEN_T) + (2.489)*abs(GEN_T)^2 + (1.451e-19)*abs(GEN_W)^3 + (0.0001326)*abs(GEN_W)^2*abs(GEN_T) + (-0.008141)*abs(GEN_W)*abs(GEN_T)^2 + (-0.004539)*abs(GEN_T)^3 +(-6.325e-23)*abs(GEN_W)^4 + (-2.091e-07)*abs(GEN_W)^3*abs(GEN_T) + ( 3.455e-06)*abs(GEN_W)^2*abs(GEN_T)^2 + ( 2.499e-05)*abs(GEN_W)*abs(GEN_T)^3 + (-5.321e-05)*abs(GEN_T)^4;

eq_c[5] := GEN_P = piecewise(GEN_T * GEN_W = 0, 0, GEN_W*GEN_T < 0,-1 * GEN_ReqPow_eq, GEN_ReqPow_eq);
eq_c[6] := GEN_A = GEN_P/GEN_V;

#GB
eq_c[7] := GBb_T = -1/GB_R * GBa_T;
eq_c[8] := GBb_W = GB_R * GBa_W;

assume(BAT_V::nonnegative);
assume(FD_W::nonnegative);
assume(GB_R::nonnegative);

termeqs := {eq_c[1],eq_c[2],eq_c[3],eq_c[4],eq_c[5],eq_c[6],eq_c[7],eq_c[8]};

sys_eqs2 := termeqs union convert(eq2,set);

drivers2:= {GB_R,ICE_T,ICE_W,FD_T,FD_W};
symvarnames2:=select(type,indets(convert(sys_eqs2,list)),name);
notdrivers2:=symvarnames2 minus drivers2;

sol2:=solve(sys_eqs2,notdrivers2) assuming real;

symb_sol2:=unapply(sol2,[drivers2[]]);

Does assume make solve work faster, or just complicate things?  Any help is greatly appreciated!

Series_noGear.mw

## Numeric vs symbolic computations...

Hi all

Please, I'd like to clarify some basic points about performing computations in Maple 18. Up to now I have been doing some numeric calcs using matrices normally composed of 10 to 15 columns and 200 to 600 rows.

When doing the calcs with a matrix of ~200 rows, it is just ok but as the number of rows increase the calculation speed reduces significantly.

The data contained in each row is calculated within a loop cycle (i.e.: for i from 1 to 200 do ......).

The number of rows is controlled by a slider so when I drag the slider the calcs are automatically updated and the results shown graphically.

As I said it is too slow so I don't know if I should be looking into the option of doing calcs symbolically first? However you can't use symbolic notation when working with matrices. I still got a lot of calcs to do but prefer not to continue as it will only get slower so better to see if I can optimise speed.

Any comment is trully appreciated.

Regards

Cesar

## System of equations solve, solutions may be lost. ...

Hi MaplePrime-ers!

I've been using the Maple(17) toolbox in Matlab(2012b) to quickly enumerate systems of equations by: (i) solving them symbolically, (ii) using unapply to make them functions, (iii) then supplying the points (driver equations) to get the system solution.  Speed is a must, because there may be 3 million+ systems to solve.  Symbolics is also very important because I am evaluating topology, so the structure of the equations may change, and therefore a functional approach will not work.

I have had success (seen in the first code snippet).  I would like similiar behaviour in the second code snippet, but sometimes I get 'solutions may be lost' as an error message,  or 'Error, (in unapply) variables must be unique and of type name'

The system of equations include:  Linear equations, 5th order polynomials, absolute functions, and pieceiwse functions.

Here is code with a topology that solves:

#Interconnection Equations
eq2[1] := FD_T + EM2_T = 0;
eq2[2] := ICE_T + GEN_T = 0;
eq2[3] := EM2_A + GEN_A + BAT_A = 0;
eq2[4] := -FD_W + EM2_W = 0;
eq2[5] := -ICE_W + GEN_W = 0;
eq2[6] := -EM2_V + GEN_V = 0;
eq2[7] := -EM2_V + BAT_V = 0;

#ICE
eq_c[1] := ICE_mdot_g=((671.5) + (-21.94)*ICE_T + (0.1942)*ICE_W + (0.5113)*ICE_T^2 + (-0.01271)*ICE_T*ICE_W + ( -0.0008761)*ICE_W^2 + (-0.006071)*ICE_T^3 + (9.867e-07)*ICE_T^2*ICE_W + (5.616e-05)*ICE_T*ICE_W^2 + (1.588e-06)*ICE_W^3 + (3.61e-05)*ICE_T^4 + (8.98e-07)*ICE_T^3*ICE_W + (-2.814e-07)*ICE_T^2*ICE_W^2 + (-8.121e-08)*ICE_T*ICE_W^3 + ( -8.494e-08 )*ICE_T^5 + (-2.444e-09)*ICE_T^4*ICE_W + (-9.311e-10)*ICE_T^3*ICE_W^2 + ( 5.835e-10)*ICE_T^2*ICE_W^3 ) *1/3600/1000 * ICE_T * ICE_W;

#BAT
eq_c[2] := BAT = 271;

#EM2
EM2_ReqPow_eq := (-148.3) + (4.267)*abs(EM2_W) + (12.77)*abs(EM2_T) + (-0.0364)*abs(EM2_W)^2 + ( 1.16)*abs(EM2_W)*abs(EM2_T) + (-0.258)*abs(EM2_T)^2 + ( 0.0001181)*abs(EM2_W)^3 + (-0.0005994)*abs(EM2_W)^2*abs(EM2_T) + ( 0.0001171)*abs(EM2_W)*abs(EM2_T)^2 + (0.001739 )*abs(EM2_T)^3 + (-1.245e-07 )*abs(EM2_W)^4 + ( 1.2e-06)*abs(EM2_W)^3*abs(EM2_T) + ( -1.584e-06)*abs(EM2_W)^2*abs(EM2_T)^2 + ( 4.383e-07)*abs(EM2_W)*abs(EM2_T)^3 + (-2.947e-06)*abs(EM2_T)^4;
eq_c[3] := EM2_P = piecewise( EM2_T = 0, 0, EM2_W = 0, 0, EM2_W*EM2_T < 0,-1 * EM2_ReqPow_eq, EM2_ReqPow_eq);
eq_c[4] := EM2_A = EM2_P/EM2_V;

#GEN
GEN_ReqPow_eq:= (-5.28e-12) + ( 3.849e-14)*abs(GEN_W) + (-71.9)*abs(GEN_T) + (-1.168e-16)*abs(GEN_W)^2 +(1.296)*abs(GEN_W)*abs(GEN_T) + (2.489)*abs(GEN_T)^2 + (1.451e-19)*abs(GEN_W)^3 + (0.0001326)*abs(GEN_W)^2*abs(GEN_T) + (-0.008141)*abs(GEN_W)*abs(GEN_T)^2 + (-0.004539)*abs(GEN_T)^3 +(-6.325e-23)*abs(GEN_W)^4 + (-2.091e-07)*abs(GEN_W)^3*abs(GEN_T) + ( 3.455e-06)*abs(GEN_W)^2*abs(GEN_T)^2 + ( 2.499e-05)*abs(GEN_W)*abs(GEN_T)^3 + (-5.321e-05)*abs(GEN_T)^4;
eq_c[5] := GEN_P = piecewise( GEN_T = 0, 0, GEN_W = 0, 0, GEN_W*GEN_T < 0,-1 * GEN_ReqPow_eq, GEN_ReqPow_eq);
eq_c[6] := GEN_A = GEN_P/GEN_V;

#ASSUMPTIONS
assume(BAT_V::nonnegative);
assume(FD_W::nonnegative);

#FINAL EQUATIONS

sys_eqs2 := convert(eq2,set) union {eq_c[1],eq_c[2],eq_c[3],eq_c[4],eq_c[5],eq_c[6]};

#Selecting which variables to solve for:

drivers2:= { ICE_T,ICE_W,FD_T,FD_W};
symvarnames2:=select(type,indets(convert(sys_eqs2,list)),name);
notdrivers2:=symvarnames2 minus drivers2;

#Symbolic solve

sol2:=solve(sys_eqs2,notdrivers2) assuming real:
symb_sol2:=unapply(sol2,convert(drivers2,list)):

#Enumerate (there will generally be about 40, not 6)

count := 0;
for i1 from 1 to 40 do
for i2 from 1 to 40 do
for i3 from 1 to 40 do
for i4 from 1 to 40 do
count := count + 1;
solsol2(count) := symb_sol2(i1,i2,i3,i4);
od;
od;
od;
od;
count;

This works great!  I would like simliar output in my second code snippet, but this time with more inputs to symb_sol.  However, if I try and change the interconnection equations a little, and add a piecewise function, and another driver... (differences in bold)

#Interconnection Equations
eq1[1] := FD_T+EM2_T = 0;
eq1[2] := ICE_T+GBb_T = 0;
eq1[3] := GEN_T+GBa_T = 0;
eq1[4] := EM2_A+GEN_A+BAT_A = 0;
eq1[5] := -FD_W+EM2_W = 0;
eq1[6] := -GEN_W+GBa_W = 0;
eq1[7] := -ICE_W+GBb_W = 0;
eq1[8] := -EM2_V+GEN_V = 0;
eq1[9] := -EM2_V+BAT_V = 0;

#ICE
eq_c[1] := ICE_mdot_g=((671.5) + (-21.94)*ICE_T + (0.1942)*ICE_W + (0.5113)*ICE_T^2 + (-0.01271)*ICE_T*ICE_W + ( -0.0008761)*ICE_W^2 + (-0.006071)*ICE_T^3 + (9.867e-07)*ICE_T^2*ICE_W + (5.616e-05)*ICE_T*ICE_W^2 + (1.588e-06)*ICE_W^3 + (3.61e-05)*ICE_T^4 + (8.98e-07)*ICE_T^3*ICE_W + (-2.814e-07)*ICE_T^2*ICE_W^2 + (-8.121e-08)*ICE_T*ICE_W^3 + ( -8.494e-08 )*ICE_T^5 + (-2.444e-09)*ICE_T^4*ICE_W + (-9.311e-10)*ICE_T^3*ICE_W^2 + ( 5.835e-10)*ICE_T^2*ICE_W^3 ) *1/3600/1000 * ICE_T * ICE_W;

#BAT
eq_c[2] := BAT = 271;

#EM2
EM2_ReqPow_eq := (-148.3) + (4.267)*abs(EM2_W) + (12.77)*abs(EM2_T) + (-0.0364)*abs(EM2_W)^2 + ( 1.16)*abs(EM2_W)*abs(EM2_T) + (-0.258)*abs(EM2_T)^2 + ( 0.0001181)*abs(EM2_W)^3 + (-0.0005994)*abs(EM2_W)^2*abs(EM2_T) + ( 0.0001171)*abs(EM2_W)*abs(EM2_T)^2 + (0.001739 )*abs(EM2_T)^3 + (-1.245e-07 )*abs(EM2_W)^4 + ( 1.2e-06)*abs(EM2_W)^3*abs(EM2_T) + ( -1.584e-06)*abs(EM2_W)^2*abs(EM2_T)^2 + ( 4.383e-07)*abs(EM2_W)*abs(EM2_T)^3 + (-2.947e-06)*abs(EM2_T)^4;
eq_c[3] := EM2_P = piecewise( EM2_T = 0, 0, EM2_W = 0, 0, EM2_W*EM2_T < 0,-1 * EM2_ReqPow_eq, EM2_ReqPow_eq);
eq_c[4] := EM2_A = EM2_P/EM2_V;

#GEN
GEN_ReqPow_eq:= (-5.28e-12) + ( 3.849e-14)*abs(GEN_W) + (-71.9)*abs(GEN_T) + (-1.168e-16)*abs(GEN_W)^2 +(1.296)*abs(GEN_W)*abs(GEN_T) + (2.489)*abs(GEN_T)^2 + (1.451e-19)*abs(GEN_W)^3 + (0.0001326)*abs(GEN_W)^2*abs(GEN_T) + (-0.008141)*abs(GEN_W)*abs(GEN_T)^2 + (-0.004539)*abs(GEN_T)^3 +(-6.325e-23)*abs(GEN_W)^4 + (-2.091e-07)*abs(GEN_W)^3*abs(GEN_T) + ( 3.455e-06)*abs(GEN_W)^2*abs(GEN_T)^2 + ( 2.499e-05)*abs(GEN_W)*abs(GEN_T)^3 + (-5.321e-05)*abs(GEN_T)^4;
eq_c[5] := GEN_P = piecewise( GEN_T = 0, 0, GEN_W = 0, 0, GEN_W*GEN_T < 0,-1 * GEN_ReqPow_eq, GEN_ReqPow_eq);
eq_c[6] := GEN_A = GEN_P/GEN_V;

#GB
FiveSpeedGearbox_R := proc(ig)
local i ,eq;
i[1]:=3.32;
i[2]:=2;
i[3]:=1.36;
i[4]:=1.01;
i[5]:=0.82;
eq:= piecewise(ig=1,i[1],ig=2, i[2],ig=3,i[3],ig=4,i[4],ig=5,i[5],1);
return eq(ig);
end proc;

eq_c[7] := GBb_T = -1/GB_R * GBa_T;
eq_c[8] := GBb_W = GB_R * GBa_W;
eq_c[9] := GB_R = FiveSpeedGearbox_R(ig);

#System Equations
sys_eqs := convert(eq1,set) union convert(eq_c,set);

#Solve for variables
symvarnames:=select(type,indets(convert(sys_eqs,list)),name);
drivers:= {ig, ICE_T,ICE_W,FD_T,FD_W};
not_drivers := symvarnames minus drivers;

#Assumptinons

assume(BAT_V::nonnegative);
assume(FD_W::nonnegative);

sol:=(solve(sys_eqs,not_drivers) assuming real);

symb_sol:=unapply(sol,convert(drivers,list)): ---> Error, (in unapply) variables must be unique and of type name

Subsequent parts don't work...

count := 0;
for i1 from 1 to 40 do
for i2 from 1 to 40 do
for i3 from 1 to 40 do
for i4 from 1 to 40 do
for i5 from 1 to 40 do
count := count + 1;
solsol2(count) := symb_sol2(i1,i2,i3,i4,5);
od;
od;
od;
od;
od;
count;

While running the last line sol:, 1 of 2 things will happen, depending on the solver. Maple17 will take a long time (30+ minutes) to solve, then report nothing, or sol will solve, but will report "some solutions have been lost".

Afterwards, evaluating symb_sol(0,0,0,0,0) will return a viable solution (real values for each of the variables).  Whereas evaluating symb_sol(0,X,0,0,0), where X <> 0, will return and empty list [].

Does anyone know how to (i) speed up the symbolic solve time?  (ii) Return ALL of the solutions?

Thanks in advance for reading this.  I've really no idea why this isn't working.  I've also attached two worksheets with the code: noGB.mw   withGB.mw

## Simplification of tensors with dummy indices...

Hello,

I am using Maple Physics for symbolic tensor computations. However, I fail to simplify quite a simple expression.

Consider the following code:

with(Physics):with(Library):

Setup(spacetimeindices = lowercaselatin):

Define(F[a]);

Simplify(%);

Here is a file with expression: example2.txt.

The expression in the example2.txt is equal to zero. The following steps allow to obtain this result: expand, contract Kronecker deltas and metric tensors and collect similar terms. This also can be verified using another software (Cadabra, Mathematica xAct, etc.). As one can see, the result of Maple Simplify(%) contains terms like -462661905780*F[k]*F[~k] - 5856479820*F[m]*F[~m] which can be futher simplified, but Maple does not do this (even when I invoke Simplify(%) several times).

What is the right sequence of manipulations needed to obtain zero?

I use the latest Physics package (39.2, updated on November 30).

Thanks,

Dmitry.

## Regrouping terms under the square root...

Hi everybody,

When doing calculations, I often run in the following problem.  I have the final solution wich I simplify symbolically so many terms are cancelling.  But I get this:

While I would like to regroup all the terms into the square root.  But look, even in this forum, Maple get sqrt(2) automatically out of the square root.

I know that it is the simple form.  But in some instances, I need the square root to stay together so I can show a property.  But is there a way to be able, sometimes, to tell Maple to leave all the terms under the square root?

```--------------------------------------
Mario Lemelin```
```Maple 17.01 Ubuntu 13.10 - 64 bitsMaple 17 Win 7 -  64 bits
messagerie : mario.lemelin@cgocable.ca
téléphone :  (819) 376-0987```

## Finding the values of coefficients in a set of lin...

I have a set of around 60 linear equations with symbolic coefficients. ie

a*x1 + b*x2 + ... + c*x60 = 1

x1 + (c-a)*x2 + ... + d*x60 = 0

...

c*x1 + d*x2 + ... + b*x60 = a

The coefficients a,b,c,d are functions of x1...x60. I am trying to find the values of these coefficients. When I had a smaller set of equations I was solving them symbolically to find x1...x60 in terms of a,b,c,d and then using this solution to solve for a,b,c,d. I can no longer solve the set of equations symbolically as it is too large. How do I find the coefficients? I had some sort of optimization routine in mind.

## Solve system of equations and inequalities with sy...

Hi guys,

I would like to solve a system of equations and inequalities with symbolic parameters (D, E, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z) for several variables (a, b, c, d, e, f, i, j, l, m, n, p, q, r, s, t, u, v).

Unfortunately the command below does not work. I get the message "Warning, solutions may have been lost".

"Solve({ l-u=0, m-v=0, n-u=0, p-v=0, Y+q-u=0, Y+r-v=0, Z+s-u=0, Z+t-v=0, (a-P*M)*l=0, (b-Q*M...

## Definition of frame with symbolic parameters...

Hello,

I would like to define my model with symbolic parameters. Consequently, i have to define the symbolic parameters and theirs values in main folder.

To illustrate, i define my parameters a1, a2 like this.

After, i need to define a frame by using the parameter a1. This frame is define like this :

## geom3d symbolic...

I don't think the geom3d package can be used symbolically it needs specific values.  Maybe I'm wrong, am I?

## A factorial sum bug?...

Who knows what Maple does wrong on this one?

 > T:=Sum(1/(6*k+1)!, k=0..infinity); evalf(T); value(T); evalf(%);
 (1)
 >